BlackRock Core Bond Portfolio

Institutional Shares | BFMCX

Semi-Annual Shareholder Report — March 31, 2025

This semi-annual shareholder report contains important information about BlackRock Core Bond Portfolio (the “Fund”) for the period of October 1, 2024 to March 31, 2025.You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441-7762.

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Class name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Institutional Shares	$22	0.43%^{Footnote Reference(a)}

Footnote	Description
Footnote^(a)	Annualized.

Fund performance

Average annual total returns

Average Annual Total Returns	6-Month Total Returns	1 Year	5 years	10 Years
Institutional Shares ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.69)%	4.47%	0.12%	1.44%
Bloomberg U.S. Aggregate Bond Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.37)	4.88	(0.40)	1.46

On September 17, 2018, the Fund acquired all of the assets, subject to the liabilities, of BlackRock Core Bond Portfolio (the “Predecessor Fund”), a series of BlackRock Funds II, through a tax-free reorganization (the “Reorganization”). The Predecessor Fund is the performance and accounting survivor of the Reorganization.

Key Fund statistics

Net Assets........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	$3,787,122,000
Number of Portfolio Holdings........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	2,534
Portfolio Turnover Rate........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	273%

Past performance is not an indication of future results. Performance results may include adjustments made for financial reporting purposes in accordance with U.S. generally accepted accounting principles. Performance results do not reflect the deduction of taxes that a shareholder would pay on fund distributions or on the redemption or sale of fund shares. Visit blackrock.com for more recent performance information.

What did the Fund invest in?

(as of March 31, 2025)

Portfolio composition

Credit quality allocation

Investment Type	Percent of Total Investments^{Footnote Reference(a)}
U.S. Government Sponsored Agency Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	35.6%
U.S. Treasury Obligations........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	22.7
Corporate Bonds........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	20.9
Non-Agency Mortgage-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	9.4
Asset-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	7.5
Foreign Government Obligations........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	2.5
Foreign Agency Obligations........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.8
Municipal Bonds........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.5
Investment Companies........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1
Other Interests........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(b)}

Credit Rating^{Footnote Reference(c)}	Percent of Total Investments^{Footnote Reference(a)}
AAA/Aaa^{Footnote Reference(d)}........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	68.0%
AA/Aa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	3.2
A........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	6.9
BBB/Baa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	16.6
BB/Ba........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1
B........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1
CC/Ca........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(b)}
N/R........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	5.1

Footnote	Description
Footnote^(a)	Excludes short-term securities, short investments and options, if any.
Footnote^(b)	Rounds to less than 0.1%.
Footnote^(c)	For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.
Footnote^(d)	The investment adviser evaluates the credit quality of unrated investments based upon certain factors including, but not limited to, credit ratings for similar investments and financial analysis of sectors, individual investments and/or issuers. Using this approach, the investment adviser has deemed unrated U.S. Government Sponsored Agency Securities and U.S. Treasury Obligations to be of similar credit quality as investments rated AAA/Aaa.

Additional information

If you wish to view additional information about the Fund, including but not limited to financial statements, the Fund’s prospectus, and proxy voting policies and procedures, please visit blackrock.com/fundreports. For proxy voting records, visit blackrock.com/proxyrecords.

The Fund is not sponsored, endorsed, issued, sold, or promoted by Bloomberg Index Services Limited and its affiliates, nor does this company make any representation regarding the advisability of investing in the Fund. BlackRock is not affiliated with the company listed above.

BlackRock Core Bond Portfolio

Institutional Shares | BFMCX

Semi-Annual Shareholder Report — March 31, 2025

BFMCX-03/25-SAR

BlackRock Core Bond Portfolio

Investor A Shares | BCBAX

Semi-Annual Shareholder Report — March 31, 2025

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Class name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Investor A Shares	$34	0.68%^{Footnote Reference(a)}

Footnote	Description
Footnote^(a)	Annualized.

Fund performance

Average annual total returns

Average Annual Total Returns	6-Month Total Returns	1 Year	5 years	10 Years
Investor A Shares ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.82)%	4.21%	(0.13)%	1.17%
Investor A Shares (with sales charge)........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(4.78)	0.04	(0.94)	0.76
Bloomberg U.S. Aggregate Bond Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.37)	4.88	(0.40)	1.46

Assuming maximum sales charges. Average annual total returns with and without sales charges reflect reductions for service fees.

Key Fund statistics

Net Assets........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	$3,787,122,000
Number of Portfolio Holdings........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	2,534
Portfolio Turnover Rate........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	273%

What did the Fund invest in?

(as of March 31, 2025)

Portfolio composition

Credit quality allocation

Investment Type	Percent of Total Investments^{Footnote Reference(a)}
U.S. Government Sponsored Agency Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	35.6%
U.S. Treasury Obligations........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	22.7
Corporate Bonds........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	20.9
Non-Agency Mortgage-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	9.4
Asset-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	7.5
Foreign Government Obligations........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	2.5
Foreign Agency Obligations........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.8
Municipal Bonds........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.5
Investment Companies........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1
Other Interests........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(b)}

Credit Rating^{Footnote Reference(c)}	Percent of Total Investments^{Footnote Reference(a)}
AAA/Aaa^{Footnote Reference(d)}........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	68.0%
AA/Aa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	3.2
A........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	6.9
BBB/Baa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	16.6
BB/Ba........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1
B........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1
CC/Ca........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(b)}
N/R........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	5.1

Footnote	Description
Footnote^(a)	Excludes short-term securities, short investments and options, if any.
Footnote^(b)	Rounds to less than 0.1%.
Footnote^(c)	For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.
Footnote^(d)	The investment adviser evaluates the credit quality of unrated investments based upon certain factors including, but not limited to, credit ratings for similar investments and financial analysis of sectors, individual investments and/or issuers. Using this approach, the investment adviser has deemed unrated U.S. Government Sponsored Agency Securities and U.S. Treasury Obligations to be of similar credit quality as investments rated AAA/Aaa.

Additional information

BlackRock Core Bond Portfolio

Investor A Shares | BCBAX

Semi-Annual Shareholder Report — March 31, 2025

BCBAX-03/25-SAR

BlackRock Core Bond Portfolio

Investor C Shares | BCBCX

Semi-Annual Shareholder Report — March 31, 2025

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Class name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Investor C Shares	$71	1.43%^{Footnote Reference(a)}

Footnote	Description
Footnote^(a)	Annualized.

Fund performance

Average annual total returns

Average Annual Total Returns	6-Month Total Returns	1 Year	5 years	10 Years
Investor C Shares ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(1.20)%	3.43%	(0.88)%	0.57%
Investor C Shares (with sales charge)........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(2.17)	2.43	(0.88)	0.57
Bloomberg U.S. Aggregate Bond Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.37)	4.88	(0.40)	1.46

Assuming maximum sales charges. Average annual total returns with and without sales charges reflect reductions for distribution and service fees.

Key Fund statistics

Net Assets........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	$3,787,122,000
Number of Portfolio Holdings........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	2,534
Portfolio Turnover Rate........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	273%

What did the Fund invest in?

(as of March 31, 2025)

Portfolio composition

Credit quality allocation

Investment Type	Percent of Total Investments^{Footnote Reference(a)}
U.S. Government Sponsored Agency Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	35.6%
U.S. Treasury Obligations........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	22.7
Corporate Bonds........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	20.9
Non-Agency Mortgage-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	9.4
Asset-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	7.5
Foreign Government Obligations........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	2.5
Foreign Agency Obligations........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.8
Municipal Bonds........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.5
Investment Companies........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1
Other Interests........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(b)}

Credit Rating^{Footnote Reference(c)}	Percent of Total Investments^{Footnote Reference(a)}
AAA/Aaa^{Footnote Reference(d)}........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	68.0%
AA/Aa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	3.2
A........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	6.9
BBB/Baa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	16.6
BB/Ba........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1
B........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1
CC/Ca........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(b)}
N/R........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	5.1

Footnote	Description
Footnote^(a)	Excludes short-term securities, short investments and options, if any.
Footnote^(b)	Rounds to less than 0.1%.
Footnote^(c)	For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.
Footnote^(d)	The investment adviser evaluates the credit quality of unrated investments based upon certain factors including, but not limited to, credit ratings for similar investments and financial analysis of sectors, individual investments and/or issuers. Using this approach, the investment adviser has deemed unrated U.S. Government Sponsored Agency Securities and U.S. Treasury Obligations to be of similar credit quality as investments rated AAA/Aaa.

Additional information

BlackRock Core Bond Portfolio

Investor C Shares | BCBCX

Semi-Annual Shareholder Report — March 31, 2025

BCBCX-03/25-SAR

BlackRock Core Bond Portfolio

Class K Shares | CCBBX

Semi-Annual Shareholder Report — March 31, 2025

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Class name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class K Shares	$19	0.38%^{Footnote Reference(a)}

Footnote	Description
Footnote^(a)	Annualized.

Fund performance

Average annual total returns

Average Annual Total Returns	6-Month Total Returns	1 Year	5 years	10 Years
Class K Shares ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.66)%	4.52%	0.18%	1.50%
Bloomberg U.S. Aggregate Bond Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.37)	4.88	(0.40)	1.46

Key Fund statistics

Net Assets........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	$3,787,122,000
Number of Portfolio Holdings........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	2,534
Portfolio Turnover Rate........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	273%

What did the Fund invest in?

(as of March 31, 2025)

Portfolio composition

Credit quality allocation

Investment Type	Percent of Total Investments^{Footnote Reference(a)}
U.S. Government Sponsored Agency Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	35.6%
U.S. Treasury Obligations........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	22.7
Corporate Bonds........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	20.9
Non-Agency Mortgage-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	9.4
Asset-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	7.5
Foreign Government Obligations........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	2.5
Foreign Agency Obligations........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.8
Municipal Bonds........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.5
Investment Companies........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1
Other Interests........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(b)}

Credit Rating^{Footnote Reference(c)}	Percent of Total Investments^{Footnote Reference(a)}
AAA/Aaa^{Footnote Reference(d)}........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	68.0%
AA/Aa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	3.2
A........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	6.9
BBB/Baa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	16.6
BB/Ba........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1
B........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1
CC/Ca........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(b)}
N/R........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	5.1

Footnote	Description
Footnote^(a)	Excludes short-term securities, short investments and options, if any.
Footnote^(b)	Rounds to less than 0.1%.
Footnote^(c)	For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.
Footnote^(d)	The investment adviser evaluates the credit quality of unrated investments based upon certain factors including, but not limited to, credit ratings for similar investments and financial analysis of sectors, individual investments and/or issuers. Using this approach, the investment adviser has deemed unrated U.S. Government Sponsored Agency Securities and U.S. Treasury Obligations to be of similar credit quality as investments rated AAA/Aaa.

Additional information

BlackRock Core Bond Portfolio

Class K Shares | CCBBX

Semi-Annual Shareholder Report — March 31, 2025

CCBBX-03/25-SAR

BlackRock Core Bond Portfolio

Class R Shares | BCBRX

Semi-Annual Shareholder Report — March 31, 2025

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Class name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class R Shares	$46	0.93%^{Footnote Reference(a)}

Footnote	Description
Footnote^(a)	Annualized.

Fund performance

Average annual total returns

Average Annual Total Returns	6-Month Total Returns	1 Year	5 years	10 Years
Class R Shares ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(1.05)%	3.95%	(0.40)%	0.92%
Bloomberg U.S. Aggregate Bond Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.37)	4.88	(0.40)	1.46

Average annual total returns reflect reductions for distribution and service fees.

Key Fund statistics

Net Assets........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	$3,787,122,000
Number of Portfolio Holdings........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	2,534
Portfolio Turnover Rate........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	273%

What did the Fund invest in?

(as of March 31, 2025)

Portfolio composition

Credit quality allocation

Investment Type	Percent of Total Investments^{Footnote Reference(a)}
U.S. Government Sponsored Agency Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	35.6%
U.S. Treasury Obligations........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	22.7
Corporate Bonds........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	20.9
Non-Agency Mortgage-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	9.4
Asset-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	7.5
Foreign Government Obligations........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	2.5
Foreign Agency Obligations........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.8
Municipal Bonds........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.5
Investment Companies........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1
Other Interests........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(b)}

Credit Rating^{Footnote Reference(c)}	Percent of Total Investments^{Footnote Reference(a)}
AAA/Aaa^{Footnote Reference(d)}........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	68.0%
AA/Aa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	3.2
A........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	6.9
BBB/Baa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	16.6
BB/Ba........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1
B........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1
CC/Ca........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(b)}
N/R........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	5.1

Footnote	Description
Footnote^(a)	Excludes short-term securities, short investments and options, if any.
Footnote^(b)	Rounds to less than 0.1%.
Footnote^(c)	For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.
Footnote^(d)	The investment adviser evaluates the credit quality of unrated investments based upon certain factors including, but not limited to, credit ratings for similar investments and financial analysis of sectors, individual investments and/or issuers. Using this approach, the investment adviser has deemed unrated U.S. Government Sponsored Agency Securities and U.S. Treasury Obligations to be of similar credit quality as investments rated AAA/Aaa.

Additional information

BlackRock Core Bond Portfolio

Class R Shares | BCBRX

Semi-Annual Shareholder Report — March 31, 2025

BCBRX-03/25-SAR

BlackRock Mortgage-Backed Securities Fund

Institutional Shares | BGNIX

Semi-Annual Shareholder Report — March 31, 2025

This semi-annual shareholder report contains important information about BlackRock Mortgage-Backed Securities Fund (the “Fund”) (formerly known as BlackRock GNMA Portfolio) for the period of October 1, 2024 to March 31, 2025.You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441-7762.

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Class name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Institutional Shares	$21	0.43%^{Footnote Reference(a)}

Footnote	Description
Footnote^(a)	Annualized.

Fund performance

Average annual total returns

Average Annual Total Returns	6-Month Total Returns	1 Year	5 years	10 Years
Institutional Shares ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.24)%	4.99%	(0.64)%	0.88%
Bloomberg U.S. Aggregate Bond Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.37)	4.88	(0.40)	1.46
Bloomberg U.S. MBS Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.20)	5.39	(0.69)	1.11
Bloomberg GNMA Total Return Index Value Unhedged USD........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.16	5.18	(0.59)	1.08

Effective January 28, 2025, the Fund has changed the benchmark against which it measures its performance from the Bloomberg GNMA Total Return Index Value Unhedged USD to the Bloomberg U.S. MBS Index. Fund management believes the Bloomberg U.S. MBS Index more accurately reflects the investment strategy of the Fund.

The Fund's returns shown prior to January 28, 2025 are the returns of the Fund when it followed different investment strategies and investment process under the name BlackRock GNMA Portfolio.

On September 17, 2018, the Fund acquired all of the assets, subject to the liabilities, of BlackRock GNMA Portfolio (the “Predecessor Fund”), a series of BlackRock Funds II, through a tax-free reorganization (the “Reorganization”). The Predecessor Fund is the performance and accounting survivor of the Reorganization.

Key Fund statistics

Net Assets........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	$265,324,836
Number of Portfolio Holdings........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	623
Portfolio Turnover Rate........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1,132%

What did the Fund invest in?

(as of March 31, 2025)

Portfolio composition

Credit quality allocation

Investment Type	Percent of Total Investments^{Footnote Reference(a)}
U.S. Government Sponsored Agency Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	98.8%
Non-Agency Mortgage-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.2

Investment Type

Percent of Total InvestmentsFootnote Reference(a)

U.S. Government Sponsored Agency Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................

98.8%

Non-Agency Mortgage-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................

1.2

Credit Rating^{Footnote Reference(b)}	Percent of Total Investments^{Footnote Reference(a)}
AAA/Aaa^{Footnote Reference(c)}........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	99.3%
N/R........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.7

Credit RatingFootnote Reference(b)

Percent of Total  InvestmentsFootnote Reference(a)

AAA/AaaFootnote Reference(c)........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................

99.3%

N/R........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................

0.7

Footnote	Description
Footnote^(a)	Excludes short-term securities, short investments and options, if any.
Footnote^(b)	For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.
Footnote^(c)	The investment adviser evaluates the credit quality of unrated investments based upon certain factors including, but not limited to, credit ratings for similar investments and financial analysis of sectors, individual investments and/or issuers. Using this approach, the investment adviser has deemed unrated U.S. Government Sponsored Agency Securities and U.S. Treasury Obligations to be of similar credit quality as investments rated AAA/Aaa.

Additional information

BlackRock Mortgage-Backed Securities Fund

Institutional Shares | BGNIX

Semi-Annual Shareholder Report — March 31, 2025

BGNIX-03/25-SAR

BlackRock Mortgage-Backed Securities Fund

Investor A Shares | BGPAX

Semi-Annual Shareholder Report — March 31, 2025

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Class name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Investor A Shares	$34	0.68%^{Footnote Reference(a)}

Footnote	Description
Footnote^(a)	Annualized.

Fund performance

Average annual total returns

Average Annual Total Returns	6-Month Total Returns	1 Year	5 years	10 Years
Investor A Shares ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.35)%	4.73%	(0.90)%	0.61%
Investor A Shares (with sales charge)........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(4.34)	0.54	(1.71)	0.20
Bloomberg U.S. Aggregate Bond Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.37)	4.88	(0.40)	1.46
Bloomberg U.S. MBS Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.20)	5.39	(0.69)	1.11
Bloomberg GNMA Total Return Index Value Unhedged USD........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.16	5.18	(0.59)	1.08

Assuming maximum sales charges. Average annual total returns with and without sales charges reflect reductions for service fees.

The Fund's returns shown prior to January 28, 2025 are the returns of the Fund when it followed different investment strategies and investment process under the name BlackRock GNMA Portfolio.

Key Fund statistics

Net Assets........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	$265,324,836
Number of Portfolio Holdings........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	623
Portfolio Turnover Rate........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1,132%

What did the Fund invest in?

(as of March 31, 2025)

Portfolio composition

Credit quality allocation

Investment Type	Percent of Total Investments^{Footnote Reference(a)}
U.S. Government Sponsored Agency Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	98.8%
Non-Agency Mortgage-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.2

Investment Type

Percent of Total InvestmentsFootnote Reference(a)

U.S. Government Sponsored Agency Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................

98.8%

Non-Agency Mortgage-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................

1.2

Credit Rating^{Footnote Reference(b)}	Percent of Total Investments^{Footnote Reference(a)}
AAA/Aaa^{Footnote Reference(c)}........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	99.3%
N/R........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.7

Credit RatingFootnote Reference(b)

Percent of Total  InvestmentsFootnote Reference(a)

AAA/AaaFootnote Reference(c)........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................

99.3%

N/R........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................

0.7

Footnote	Description
Footnote^(a)	Excludes short-term securities, short investments and options, if any.
Footnote^(b)	For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.
Footnote^(c)	The investment adviser evaluates the credit quality of unrated investments based upon certain factors including, but not limited to, credit ratings for similar investments and financial analysis of sectors, individual investments and/or issuers. Using this approach, the investment adviser has deemed unrated U.S. Government Sponsored Agency Securities and U.S. Treasury Obligations to be of similar credit quality as investments rated AAA/Aaa.

Additional information

BlackRock Mortgage-Backed Securities Fund

Investor A Shares | BGPAX

Semi-Annual Shareholder Report — March 31, 2025

BGPAX-03/25-SAR

BlackRock Mortgage-Backed Securities Fund

Investor C Shares | BGPCX

Semi-Annual Shareholder Report — March 31, 2025

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Class name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Investor C Shares	$71	1.43%^{Footnote Reference(a)}

Footnote	Description
Footnote^(a)	Annualized.

Fund performance

Average annual total returns

Average Annual Total Returns	6-Month Total Returns	1 Year	5 years	10 Years
Investor C Shares ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.73)%	3.96%	(1.63)%	0.02%
Investor C Shares (with sales charge)........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(1.71)	2.96	(1.63)	0.02
Bloomberg U.S. Aggregate Bond Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.37)	4.88	(0.40)	1.46
Bloomberg U.S. MBS Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.20)	5.39	(0.69)	1.11
Bloomberg GNMA Total Return Index Value Unhedged USD........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.16	5.18	(0.59)	1.08

Assuming maximum sales charges. Average annual total returns with and without sales charges reflect reductions for distribution and service fees.

The Fund's returns shown prior to January 28, 2025 are the returns of the Fund when it followed different investment strategies and investment process under the name BlackRock GNMA Portfolio.

Key Fund statistics

Net Assets........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	$265,324,836
Number of Portfolio Holdings........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	623
Portfolio Turnover Rate........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1,132%

What did the Fund invest in?

(as of March 31, 2025)

Portfolio composition

Credit quality allocation

Investment Type

Percent of Total InvestmentsFootnote Reference(a)

U.S. Government Sponsored Agency Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................

98.8%

Non-Agency Mortgage-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................

1.2

Credit RatingFootnote Reference(b)

Percent of Total  InvestmentsFootnote Reference(a)

AAA/AaaFootnote Reference(c)........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................

99.3%

N/R........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................

0.7

Footnote	Description
Footnote^(a)	Excludes short-term securities, short investments and options, if any.
Footnote^(b)	For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.
Footnote^(c)	The investment adviser evaluates the credit quality of unrated investments based upon certain factors including, but not limited to, credit ratings for similar investments and financial analysis of sectors, individual investments and/or issuers. Using this approach, the investment adviser has deemed unrated U.S. Government Sponsored Agency Securities and U.S. Treasury Obligations to be of similar credit quality as investments rated AAA/Aaa.

Additional information

BlackRock Mortgage-Backed Securities Fund

Investor C Shares | BGPCX

Semi-Annual Shareholder Report — March 31, 2025

BGPCX-03/25-SAR

BlackRock Mortgage-Backed Securities Fund

Class K Shares | BBGPX

Semi-Annual Shareholder Report — March 31, 2025

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Class name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class K Shares	$19	0.38%^{Footnote Reference(a)}

Footnote	Description
Footnote^(a)	Annualized.

Fund performance

Average annual total returns

Average Annual Total Returns	6-Month Total Returns	1 Year	5 years	10 Years
Class K Shares ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.10)%	5.18%	(0.58)%	0.94%
Bloomberg U.S. Aggregate Bond Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.37)	4.88	(0.40)	1.46
Bloomberg U.S. MBS Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.20)	5.39	(0.69)	1.11
Bloomberg GNMA Total Return Index Value Unhedged USD........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.16	5.18	(0.59)	1.08

The Fund's returns shown prior to January 28, 2025 are the returns of the Fund when it followed different investment strategies and investment process under the name BlackRock GNMA Portfolio.

Key Fund statistics

Net Assets........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	$265,324,836
Number of Portfolio Holdings........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	623
Portfolio Turnover Rate........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1,132%

What did the Fund invest in?

(as of March 31, 2025)

Portfolio composition

Credit quality allocation

Investment Type

Percent of Total InvestmentsFootnote Reference(a)

U.S. Government Sponsored Agency Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................

98.8%

Non-Agency Mortgage-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................

1.2

Credit RatingFootnote Reference(b)

Percent of Total  InvestmentsFootnote Reference(a)

AAA/AaaFootnote Reference(c)........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................

99.3%

N/R........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................

0.7

Footnote	Description
Footnote^(a)	Excludes short-term securities, short investments and options, if any.
Footnote^(b)	For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.
Footnote^(c)	The investment adviser evaluates the credit quality of unrated investments based upon certain factors including, but not limited to, credit ratings for similar investments and financial analysis of sectors, individual investments and/or issuers. Using this approach, the investment adviser has deemed unrated U.S. Government Sponsored Agency Securities and U.S. Treasury Obligations to be of similar credit quality as investments rated AAA/Aaa.

Additional information

BlackRock Mortgage-Backed Securities Fund

Class K Shares | BBGPX

Semi-Annual Shareholder Report — March 31, 2025

BBGPX-03/25-SAR

BlackRock High Yield Portfolio

Institutional Shares | BHYIX

Semi-Annual Shareholder Report — March 31, 2025

This semi-annual shareholder report contains important information about BlackRock High Yield Portfolio (the “Fund”) for the period of October 1, 2024 to March 31, 2025.You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441-7762.

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Class name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Institutional Shares	$28	0.56%^{Footnote Reference(a)}

Footnote	Description
Footnote^(a)	Annualized.

Fund performance

Average annual total returns

Average Annual Total Returns	6-Month Total Returns	1 Year	5 years	10 Years
Institutional Shares ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.17%	7.34%	7.60%	4.95%
Bloomberg U.S. Universal Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.15)	5.24	0.32	1.83
Bloomberg U.S. Corporate High Yield 2% Issuer Capped Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.18	7.69	7.28	5.01

On September 17, 2018, the Fund acquired all of the assets, subject to the liabilities, of BlackRock High Yield Bond Portfolio (the “Predecessor Fund”), a series of BlackRock Funds II, through a tax-free reorganization (the “Reorganization”). The Predecessor Fund is the performance and accounting survivor of the Reorganization.

Key Fund statistics

Net Assets........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	$26,839,596,596
Number of Portfolio Holdings........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1,514
Portfolio Turnover Rate........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	31%

What did the Fund invest in?

(as of March 31, 2025)

Portfolio composition

Credit quality allocation

Investment Type	Percent of Total Investments^{Footnote Reference(a)}
Corporate Bonds........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	86.8%
Floating Rate Loan Interests........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	7.3
Investment Companies........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	2.4
Preferred Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.5
Fixed Rate Loan Interests........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.4
Common Stocks........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.5
Asset-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1
Foreign Agency Obligations........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(b)}
Other Interests........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(b)}

Credit Rating^{Footnote Reference(c)}	Percent of Total Investments^{Footnote Reference(a)}
A........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1%
BBB/Baa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	5.1
BB/Ba........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	35.8
B........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	46.5
CCC/Caa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	9.0
CC/Ca........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(b)}
N/R........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	3.5

Footnote	Description
Footnote^(a)	Excludes short-term securities, short investments and options, if any.
Footnote^(b)	Rounds to less than 0.1%.
Footnote^(c)	For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.

Additional information

BlackRock High Yield Portfolio

Institutional Shares | BHYIX

Semi-Annual Shareholder Report — March 31, 2025

BHYIX-03/25-SAR

BlackRock High Yield Portfolio

Service Shares | BHYSX

Semi-Annual Shareholder Report — March 31, 2025

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Class name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Service Shares	$45	0.90%^{Footnote Reference(a)}

Footnote	Description
Footnote^(a)	Annualized.

Fund performance

Average annual total returns

Average Annual Total Returns	6-Month Total Returns	1 Year	5 years	10 Years
Service Shares ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.85%	6.85%	7.26%	4.64%
Bloomberg U.S. Universal Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.15)	5.24	0.32	1.83
Bloomberg U.S. Corporate High Yield 2% Issuer Capped Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.18	7.69	7.28	5.01

Average annual total returns reflect reductions for service fees.

Key Fund statistics

Net Assets........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	$26,839,596,596
Number of Portfolio Holdings........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1,514
Portfolio Turnover Rate........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	31%

What did the Fund invest in?

(as of March 31, 2025)

Portfolio composition

Credit quality allocation

Investment Type	Percent of Total Investments^{Footnote Reference(a)}
Corporate Bonds........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	86.8%
Floating Rate Loan Interests........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	7.3
Investment Companies........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	2.4
Preferred Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.5
Fixed Rate Loan Interests........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.4
Common Stocks........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.5
Asset-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1
Foreign Agency Obligations........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(b)}
Other Interests........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(b)}

Credit Rating^{Footnote Reference(c)}	Percent of Total Investments^{Footnote Reference(a)}
A........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1%
BBB/Baa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	5.1
BB/Ba........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	35.8
B........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	46.5
CCC/Caa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	9.0
CC/Ca........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(b)}
N/R........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	3.5

Footnote	Description
Footnote^(a)	Excludes short-term securities, short investments and options, if any.
Footnote^(b)	Rounds to less than 0.1%.
Footnote^(c)	For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.

Additional information

BlackRock High Yield Portfolio

Service Shares | BHYSX

Semi-Annual Shareholder Report — March 31, 2025

BHYSX-03/25-SAR

BlackRock High Yield Portfolio

Investor A Shares | BHYAX

Semi-Annual Shareholder Report — March 31, 2025

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Class name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Investor A Shares	$46	0.91%^{Footnote Reference(a)}

Footnote	Description
Footnote^(a)	Annualized.

Fund performance

Average annual total returns

Average Annual Total Returns	6-Month Total Returns	1 Year	5 years	10 Years
Investor A Shares ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.99%	6.96%	7.24%	4.61%
Investor A Shares (with sales charge)........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(3.05)	2.68	6.37	4.18
Bloomberg U.S. Universal Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.15)	5.24	0.32	1.83
Bloomberg U.S. Corporate High Yield 2% Issuer Capped Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.18	7.69	7.28	5.01

Assuming maximum sales charges. Average annual total returns with and without sales charges reflect reductions for service fees.

Key Fund statistics

Net Assets........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	$26,839,596,596
Number of Portfolio Holdings........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1,514
Portfolio Turnover Rate........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	31%

What did the Fund invest in?

(as of March 31, 2025)

Portfolio composition

Credit quality allocation

Investment Type	Percent of Total Investments^{Footnote Reference(a)}
Corporate Bonds........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	86.8%
Floating Rate Loan Interests........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	7.3
Investment Companies........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	2.4
Preferred Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.5
Fixed Rate Loan Interests........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.4
Common Stocks........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.5
Asset-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1
Foreign Agency Obligations........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(b)}
Other Interests........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(b)}

Credit Rating^{Footnote Reference(c)}	Percent of Total Investments^{Footnote Reference(a)}
A........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1%
BBB/Baa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	5.1
BB/Ba........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	35.8
B........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	46.5
CCC/Caa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	9.0
CC/Ca........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(b)}
N/R........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	3.5

Footnote	Description
Footnote^(a)	Excludes short-term securities, short investments and options, if any.
Footnote^(b)	Rounds to less than 0.1%.
Footnote^(c)	For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.

Additional information

BlackRock High Yield Portfolio

Investor A Shares | BHYAX

Semi-Annual Shareholder Report — March 31, 2025

BHYAX-03/25-SAR

BlackRock High Yield Portfolio

Investor C Shares | BHYCX

Semi-Annual Shareholder Report — March 31, 2025

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Class name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Investor C Shares	$78	1.56%^{Footnote Reference(a)}

Footnote	Description
Footnote^(a)	Annualized.

Fund performance

Average annual total returns

Average Annual Total Returns	6-Month Total Returns	1 Year	5 years	10 Years
Investor C Shares ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.67%	6.28%	6.53%	4.02%
Investor C Shares (with sales charge)........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.31)	5.29	6.53	4.02
Bloomberg U.S. Universal Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.15)	5.24	0.32	1.83
Bloomberg U.S. Corporate High Yield 2% Issuer Capped Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.18	7.69	7.28	5.01

Assuming maximum sales charges. Average annual total returns with and without sales charges reflect reductions for distribution and service fees.

Key Fund statistics

Net Assets........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	$26,839,596,596
Number of Portfolio Holdings........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1,514
Portfolio Turnover Rate........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	31%

What did the Fund invest in?

(as of March 31, 2025)

Portfolio composition

Credit quality allocation

Investment Type	Percent of Total Investments^{Footnote Reference(a)}
Corporate Bonds........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	86.8%
Floating Rate Loan Interests........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	7.3
Investment Companies........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	2.4
Preferred Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.5
Fixed Rate Loan Interests........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.4
Common Stocks........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.5
Asset-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1
Foreign Agency Obligations........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(b)}
Other Interests........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(b)}

Credit Rating^{Footnote Reference(c)}	Percent of Total Investments^{Footnote Reference(a)}
A........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1%
BBB/Baa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	5.1
BB/Ba........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	35.8
B........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	46.5
CCC/Caa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	9.0
CC/Ca........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(b)}
N/R........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	3.5

Footnote	Description
Footnote^(a)	Excludes short-term securities, short investments and options, if any.
Footnote^(b)	Rounds to less than 0.1%.
Footnote^(c)	For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.

Additional information

BlackRock High Yield Portfolio

Investor C Shares | BHYCX

Semi-Annual Shareholder Report — March 31, 2025

BHYCX-03/25-SAR

BlackRock High Yield Portfolio

Class K Shares | BRHYX

Semi-Annual Shareholder Report — March 31, 2025

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Class name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class K Shares	$23	0.46%^{Footnote Reference(a)}

Footnote	Description
Footnote^(a)	Annualized.

Fund performance

Average annual total returns

Average Annual Total Returns	6-Month Total Returns	1 Year	5 years	10 Years
Class K Shares ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.08%	7.29%	7.67%	5.04%
Bloomberg U.S. Universal Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.15)	5.24	0.32	1.83
Bloomberg U.S. Corporate High Yield 2% Issuer Capped Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.18	7.69	7.28	5.01

Key Fund statistics

Net Assets........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	$26,839,596,596
Number of Portfolio Holdings........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1,514
Portfolio Turnover Rate........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	31%

What did the Fund invest in?

(as of March 31, 2025)

Portfolio composition

Credit quality allocation

Investment Type	Percent of Total Investments^{Footnote Reference(a)}
Corporate Bonds........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	86.8%
Floating Rate Loan Interests........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	7.3
Investment Companies........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	2.4
Preferred Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.5
Fixed Rate Loan Interests........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.4
Common Stocks........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.5
Asset-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1
Foreign Agency Obligations........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(b)}
Other Interests........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(b)}

Credit Rating^{Footnote Reference(c)}	Percent of Total Investments^{Footnote Reference(a)}
A........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1%
BBB/Baa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	5.1
BB/Ba........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	35.8
B........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	46.5
CCC/Caa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	9.0
CC/Ca........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(b)}
N/R........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	3.5

Footnote	Description
Footnote^(a)	Excludes short-term securities, short investments and options, if any.
Footnote^(b)	Rounds to less than 0.1%.
Footnote^(c)	For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.

Additional information

BlackRock High Yield Portfolio

Class K Shares | BRHYX

Semi-Annual Shareholder Report — March 31, 2025

BRHYX-03/25-SAR

BlackRock High Yield Portfolio

Class R Shares | BHYRX

Semi-Annual Shareholder Report — March 31, 2025

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Class name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class R Shares	$56	1.12%^{Footnote Reference(a)}

Footnote	Description
Footnote^(a)	Annualized.

Fund performance

Average annual total returns

Average Annual Total Returns	6-Month Total Returns	1 Year	5 years	10 Years
Class R Shares ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.88%	6.72%	6.98%	4.32%
Bloomberg U.S. Universal Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.15)	5.24	0.32	1.83
Bloomberg U.S. Corporate High Yield 2% Issuer Capped Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.18	7.69	7.28	5.01

Average annual total returns reflect reductions for distribution and service fees.

Key Fund statistics

Net Assets........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	$26,839,596,596
Number of Portfolio Holdings........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1,514
Portfolio Turnover Rate........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	31%

What did the Fund invest in?

(as of March 31, 2025)

Portfolio composition

Credit quality allocation

Investment Type	Percent of Total Investments^{Footnote Reference(a)}
Corporate Bonds........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	86.8%
Floating Rate Loan Interests........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	7.3
Investment Companies........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	2.4
Preferred Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.5
Fixed Rate Loan Interests........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.4
Common Stocks........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.5
Asset-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1
Foreign Agency Obligations........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(b)}
Other Interests........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(b)}

Credit Rating^{Footnote Reference(c)}	Percent of Total Investments^{Footnote Reference(a)}
A........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1%
BBB/Baa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	5.1
BB/Ba........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	35.8
B........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	46.5
CCC/Caa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	9.0
CC/Ca........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(b)}
N/R........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	3.5

Footnote	Description
Footnote^(a)	Excludes short-term securities, short investments and options, if any.
Footnote^(b)	Rounds to less than 0.1%.
Footnote^(c)	For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.

Additional information

BlackRock High Yield Portfolio

Class R Shares | BHYRX

Semi-Annual Shareholder Report — March 31, 2025

BHYRX-03/25-SAR

BlackRock Impact Mortgage Fund

Institutional Shares | PNIGX

Semi-Annual Shareholder Report — March 31, 2025

This semi-annual shareholder report contains important information about BlackRock Impact Mortgage Fund (the “Fund”) for the period of October 1, 2024 to March 31, 2025.You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441-7762.

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Class name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Institutional Shares	$46	0.93%^{Footnote Reference(a)}

Footnote	Description
Footnote^(a)	Annualized.

Fund performance

Average annual total returns

Average Annual Total Returns	6-Month Total Returns	1 Year	5 years	10 Years
Institutional Shares ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.40)%	5.30%	(1.00)%	0.94%
Bloomberg U.S. Aggregate Bond Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.37)	4.88	(0.40)	1.46
Bloomberg U.S. MBS Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.20)	5.39	(0.69)	1.11

The Fund's returns shown prior to September 1, 2022 are the returns of the Fund when it followed a different investment objective and different investment strategies and process under the name BlackRock U.S. Government Bond Portfolio.

On September 17, 2018, the Fund acquired all of the assets, subject to the liabilities, of BlackRock U.S. Government Bond Portfolio (the “Predecessor Fund”), a series of BlackRock Funds II, through a tax-free reorganization (the “Reorganization”). The Predecessor Fund was the performance and accounting survivor of the Reorganization.

Key Fund statistics

Net Assets........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	$262,846,956
Number of Portfolio Holdings........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	373
Portfolio Turnover Rate........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1,170%

What did the Fund invest in?

(as of March 31, 2025)

Portfolio composition

Credit quality allocation

Investment Type	Percent of Total Investments^{Footnote Reference(a)}
U.S. Government Sponsored Agency Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	99.2%
Non-Agency Mortgage-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.8
Asset-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(b)}

Credit Rating^{Footnote Reference(c)}	Percent of Total Investments^{Footnote Reference(a)}
AAA/Aaa^{Footnote Reference(d)}........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	99.7%
AA/Aa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(b)}
BBB/Baa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1
N/R........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.2

Footnote	Description
Footnote^(a)	Excludes short-term securities, short investments and options, if any.
Footnote^(b)	Rounds to less than 0.1%.
Footnote^(c)	For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.
Footnote^(d)	The investment adviser evaluates the credit quality of unrated investments based upon certain factors including, but not limited to, credit ratings for similar investments and financial analysis of sectors, individual investments and/or issuers. Using this approach, the investment adviser has deemed unrated U.S. Government Sponsored Agency Securities and U.S. Treasury Obligations to be of similar credit quality as investments rated AAA/Aaa.

Additional information

BlackRock Impact Mortgage Fund

Institutional Shares | PNIGX

Semi-Annual Shareholder Report — March 31, 2025

PNIGX-03/25-SAR

BlackRock Impact Mortgage Fund

Investor A Shares | CIGAX

Semi-Annual Shareholder Report — March 31, 2025

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Class name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Investor A Shares	$59	1.18%^{Footnote Reference(a)}

Footnote	Description
Footnote^(a)	Annualized.

Fund performance

Average annual total returns

Average Annual Total Returns	6-Month Total Returns	1 Year	5 years	10 Years
Investor A Shares ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.52)%	5.04%	(1.26)%	0.67%
Investor A Shares (with sales charge)........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(4.50)	0.84	(2.06)	0.26
Bloomberg U.S. Aggregate Bond Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.37)	4.88	(0.40)	1.46
Bloomberg U.S. MBS Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.20)	5.39	(0.69)	1.11

Assuming maximum sales charges. Average annual total returns with and without sales charges reflect reductions for service fees.

Key Fund statistics

Net Assets........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	$262,846,956
Number of Portfolio Holdings........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	373
Portfolio Turnover Rate........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1,170%

What did the Fund invest in?

(as of March 31, 2025)

Portfolio composition

Credit quality allocation

Investment Type	Percent of Total Investments^{Footnote Reference(a)}
U.S. Government Sponsored Agency Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	99.2%
Non-Agency Mortgage-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.8
Asset-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(b)}

Credit Rating^{Footnote Reference(c)}	Percent of Total Investments^{Footnote Reference(a)}
AAA/Aaa^{Footnote Reference(d)}........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	99.7%
AA/Aa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(b)}
BBB/Baa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1
N/R........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.2

Footnote	Description
Footnote^(a)	Excludes short-term securities, short investments and options, if any.
Footnote^(b)	Rounds to less than 0.1%.
Footnote^(c)	For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.
Footnote^(d)	The investment adviser evaluates the credit quality of unrated investments based upon certain factors including, but not limited to, credit ratings for similar investments and financial analysis of sectors, individual investments and/or issuers. Using this approach, the investment adviser has deemed unrated U.S. Government Sponsored Agency Securities and U.S. Treasury Obligations to be of similar credit quality as investments rated AAA/Aaa.

Additional information

BlackRock Impact Mortgage Fund

Investor A Shares | CIGAX

Semi-Annual Shareholder Report — March 31, 2025

CIGAX-03/25-SAR

BlackRock Impact Mortgage Fund

Investor C Shares | BIGCX

Semi-Annual Shareholder Report — March 31, 2025

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Class name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Investor C Shares	$96	1.93%^{Footnote Reference(a)}

Footnote	Description
Footnote^(a)	Annualized.

Fund performance

Average annual total returns

Average Annual Total Returns	6-Month Total Returns	1 Year	5 years	10 Years
Investor C Shares ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(1.00)%	4.15%	(2.00)%	0.06%
Investor C Shares (with sales charge)........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(1.97)	3.15	(2.00)	0.06
Bloomberg U.S. Aggregate Bond Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.37)	4.88	(0.40)	1.46
Bloomberg U.S. MBS Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.20)	5.39	(0.69)	1.11

Assuming maximum sales charges. Average annual total returns with and without sales charges reflect reductions for distribution and service fees.

Key Fund statistics

Net Assets........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	$262,846,956
Number of Portfolio Holdings........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	373
Portfolio Turnover Rate........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1,170%

What did the Fund invest in?

(as of March 31, 2025)

Portfolio composition

Credit quality allocation

Investment Type	Percent of Total Investments^{Footnote Reference(a)}
U.S. Government Sponsored Agency Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	99.2%
Non-Agency Mortgage-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.8
Asset-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(b)}

Credit Rating^{Footnote Reference(c)}	Percent of Total Investments^{Footnote Reference(a)}
AAA/Aaa^{Footnote Reference(d)}........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	99.7%
AA/Aa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(b)}
BBB/Baa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1
N/R........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.2

Footnote	Description
Footnote^(a)	Excludes short-term securities, short investments and options, if any.
Footnote^(b)	Rounds to less than 0.1%.
Footnote^(c)	For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.
Footnote^(d)	The investment adviser evaluates the credit quality of unrated investments based upon certain factors including, but not limited to, credit ratings for similar investments and financial analysis of sectors, individual investments and/or issuers. Using this approach, the investment adviser has deemed unrated U.S. Government Sponsored Agency Securities and U.S. Treasury Obligations to be of similar credit quality as investments rated AAA/Aaa.

Additional information

BlackRock Impact Mortgage Fund

Investor C Shares | BIGCX

Semi-Annual Shareholder Report — March 31, 2025

BIGCX-03/25-SAR

BlackRock Impact Mortgage Fund

Class K Shares | BIGLX

Semi-Annual Shareholder Report — March 31, 2025

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Class name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class K Shares	$44	0.88%^{Footnote Reference(a)}

Footnote	Description
Footnote^(a)	Annualized.

Fund performance

Average annual total returns

Average Annual Total Returns	6-Month Total Returns	1 Year	5 years	10 Years
Class K Shares ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.37)%	5.36%	(0.95)%	0.98%
Bloomberg U.S. Aggregate Bond Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.37)	4.88	(0.40)	1.46
Bloomberg U.S. MBS Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.20)	5.39	(0.69)	1.11

Performance shown prior to the Class K Shares inception date of January 25, 2018 is that of Institutional Shares. The performance of Class K Shares would be substantially similar to Institutional Shares because Class K Shares and Institutional Shares invest in the same portfolio of securities and performance would only differ to the extent that Class K Shares and Institutional Shares have different expenses. The actual returns of Class K Shares would have been higher than those of the Institutional Shares because Class K Shares have lower expenses than the Institutional Shares.

Key Fund statistics

Net Assets........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	$262,846,956
Number of Portfolio Holdings........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	373
Portfolio Turnover Rate........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1,170%

What did the Fund invest in?

(as of March 31, 2025)

Portfolio composition

Credit quality allocation

Investment Type	Percent of Total Investments^{Footnote Reference(a)}
U.S. Government Sponsored Agency Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	99.2%
Non-Agency Mortgage-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.8
Asset-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(b)}

Credit Rating^{Footnote Reference(c)}	Percent of Total Investments^{Footnote Reference(a)}
AAA/Aaa^{Footnote Reference(d)}........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	99.7%
AA/Aa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(b)}
BBB/Baa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1
N/R........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.2

Footnote	Description
Footnote^(a)	Excludes short-term securities, short investments and options, if any.
Footnote^(b)	Rounds to less than 0.1%.
Footnote^(c)	For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.
Footnote^(d)	The investment adviser evaluates the credit quality of unrated investments based upon certain factors including, but not limited to, credit ratings for similar investments and financial analysis of sectors, individual investments and/or issuers. Using this approach, the investment adviser has deemed unrated U.S. Government Sponsored Agency Securities and U.S. Treasury Obligations to be of similar credit quality as investments rated AAA/Aaa.

Additional information

BlackRock Impact Mortgage Fund

Class K Shares | BIGLX

Semi-Annual Shareholder Report — March 31, 2025

BIGLX-03/25-SAR

BlackRock Impact Mortgage Fund

Class R Shares | BGBRX

Semi-Annual Shareholder Report — March 31, 2025

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Class name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class R Shares	$71	1.43%^{Footnote Reference(a)}

Footnote	Description
Footnote^(a)	Annualized.

Fund performance

Average annual total returns

Average Annual Total Returns	6-Month Total Returns	1 Year	5 years	10 Years
Class R Shares ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.64)%	4.78%	(1.50)%	0.43%
Bloomberg U.S. Aggregate Bond Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.37)	4.88	(0.40)	1.46
Bloomberg U.S. MBS Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.20)	5.39	(0.69)	1.11

Average annual total returns reflect reductions for distribution and service fees.

Key Fund statistics

Net Assets........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	$262,846,956
Number of Portfolio Holdings........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	373
Portfolio Turnover Rate........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1,170%

What did the Fund invest in?

(as of March 31, 2025)

Portfolio composition

Credit quality allocation

Investment Type	Percent of Total Investments^{Footnote Reference(a)}
U.S. Government Sponsored Agency Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	99.2%
Non-Agency Mortgage-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.8
Asset-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(b)}

Credit Rating^{Footnote Reference(c)}	Percent of Total Investments^{Footnote Reference(a)}
AAA/Aaa^{Footnote Reference(d)}........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	99.7%
AA/Aa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(b)}
BBB/Baa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1
N/R........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.2

Footnote	Description
Footnote^(a)	Excludes short-term securities, short investments and options, if any.
Footnote^(b)	Rounds to less than 0.1%.
Footnote^(c)	For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.
Footnote^(d)	The investment adviser evaluates the credit quality of unrated investments based upon certain factors including, but not limited to, credit ratings for similar investments and financial analysis of sectors, individual investments and/or issuers. Using this approach, the investment adviser has deemed unrated U.S. Government Sponsored Agency Securities and U.S. Treasury Obligations to be of similar credit quality as investments rated AAA/Aaa.

Additional information

BlackRock Impact Mortgage Fund

Class R Shares | BGBRX

Semi-Annual Shareholder Report — March 31, 2025

BGBRX-03/25-SAR

BlackRock Income Fund

Institutional Shares | BMSIX

Semi-Annual Shareholder Report — March 31, 2025

This semi-annual shareholder report contains important information about BlackRock Income Fund (the “Fund”) for the period of October 1, 2024 to March 31, 2025.You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441-7762.

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Class name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Institutional Shares	$31	0.62%^{Footnote Reference(a)}

Footnote	Description
Footnote^(a)	Annualized.

Fund performance

Average annual total returns

Average Annual Total Returns	6-Month Total Returns	1 Year	5 years	10 Years
Institutional Shares ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.19%	6.39%	4.88%	3.59%
Bloomberg U.S. Universal Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.15)	5.24	0.32	1.83
Customized Reference Benchmark........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.92	7.57	5.66	4.12

On September 17, 2018, the Fund acquired all of the assets, subject to the liabilities, of BlackRock Credit Strategies Income Fund (the “Predecessor Fund”), a series of BlackRock Funds II, through a tax-free reorganization (the “Reorganization”). The Predecessor Fund is the performance and accounting survivor of the Reorganization.

The Fund's returns shown prior to July 1, 2016 are the returns of the Predecessor Fund when it followed a different investment objective and different investment strategies under the name BlackRock Secured Credit Portfolio.

The Customized Reference Benchmark is comprised of the returns of the Bloomberg Global High Yield 100% Hedged USD Index (25%), the Morningstar LSTA Leveraged Loan Index (25%), the Bloomberg U.S. CMBS Investment Grade Index (25%) and the JPMorgan Corporate Emerging Markets Bond Index Broad Diversified (CEMBI Broad Diversified) (25%).

Key Fund statistics

Net Assets........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	$1,167,786,636
Number of Portfolio Holdings........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	2,015
Portfolio Turnover Rate........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	156%

What did the Fund invest in?

(as of March 31, 2025)

Portfolio composition

Credit quality allocation

Investment Type	Percent of Total Investments^{Footnote Reference(a)}
Corporate Bonds........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	39.0%
Asset-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	25.4
U.S. Government Sponsored Agency Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	14.0
Floating Rate Loan Interests........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	13.0
Foreign Government Obligations........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	3.2
Investment Companies........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	3.1
Foreign Agency Obligations........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.8
Non-Agency Mortgage-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.7
Preferred Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.6
Common Stocks........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1
Other^{Footnote Reference(b)}........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1

Credit Rating^{Footnote Reference(c)}	Percent of Total Investments^{Footnote Reference(a)}
AAA/Aaa^{Footnote Reference(d)}........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	30.8%
AA/Aa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	2.4
A........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	10.9
BBB/Baa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	22.3
BB/Ba........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	13.5
B........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	11.7
CCC/Caa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.6
CC/Ca........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1
N/R........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	6.7

Footnote	Description
Footnote^(a)	Excludes short-term securities, short investments and options, if any.
Footnote^(b)	Ten largest investment types are presented. Additional investment types are found in Other.
Footnote^(c)	For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.
Footnote^(d)	The investment adviser evaluates the credit quality of unrated investments based upon certain factors including, but not limited to, credit ratings for similar investments and financial analysis of sectors, individual investments and/or issuers. Using this approach, the investment adviser has deemed unrated U.S. Government Sponsored Agency Securities and U.S. Treasury Obligations to be of similar credit quality as investments rated AAA/Aaa.

Additional information

The Fund is not sponsored, endorsed, issued, sold, or promoted by Bloomberg Index Services Limited, JPMorgan Securities, LLC, Morningstar, Inc., and their respective affiliates, nor does this company make any representation regarding the advisability of investing in the Fund. BlackRock is not affiliated with the company listed above.

BlackRock Income Fund

Institutional Shares | BMSIX

Semi-Annual Shareholder Report — March 31, 2025

BMSIX-03/25-SAR

BlackRock Income Fund

Investor A Shares | BMSAX

Semi-Annual Shareholder Report — March 31, 2025

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Class name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Investor A Shares	$44	0.87%^{Footnote Reference(a)}

Footnote	Description
Footnote^(a)	Annualized.

Fund performance

Average annual total returns

Average Annual Total Returns	6-Month Total Returns	1 Year	5 years	10 Years
Investor A Shares ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.06%	6.13%	4.62%	3.33%
Investor A Shares (with sales charge)........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(1.46)	3.48	4.09	3.07
Bloomberg U.S. Universal Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.15)	5.24	0.32	1.83
Customized Reference Benchmark........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.92	7.57	5.66	4.12

Assuming maximum sales charges. Average annual total returns with and without sales charges reflect reductions for service fees.

Key Fund statistics

Net Assets........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	$1,167,786,636
Number of Portfolio Holdings........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	2,015
Portfolio Turnover Rate........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	156%

What did the Fund invest in?

(as of March 31, 2025)

Portfolio composition

Credit quality allocation

Investment Type	Percent of Total Investments^{Footnote Reference(a)}
Corporate Bonds........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	39.0%
Asset-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	25.4
U.S. Government Sponsored Agency Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	14.0
Floating Rate Loan Interests........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	13.0
Foreign Government Obligations........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	3.2
Investment Companies........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	3.1
Foreign Agency Obligations........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.8
Non-Agency Mortgage-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.7
Preferred Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.6
Common Stocks........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1
Other^{Footnote Reference(b)}........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1

Credit Rating^{Footnote Reference(c)}	Percent of Total Investments^{Footnote Reference(a)}
AAA/Aaa^{Footnote Reference(d)}........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	30.8%
AA/Aa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	2.4
A........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	10.9
BBB/Baa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	22.3
BB/Ba........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	13.5
B........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	11.7
CCC/Caa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.6
CC/Ca........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1
N/R........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	6.7

Footnote	Description
Footnote^(a)	Excludes short-term securities, short investments and options, if any.
Footnote^(b)	Ten largest investment types are presented. Additional investment types are found in Other.
Footnote^(c)	For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.
Footnote^(d)	The investment adviser evaluates the credit quality of unrated investments based upon certain factors including, but not limited to, credit ratings for similar investments and financial analysis of sectors, individual investments and/or issuers. Using this approach, the investment adviser has deemed unrated U.S. Government Sponsored Agency Securities and U.S. Treasury Obligations to be of similar credit quality as investments rated AAA/Aaa.

Additional information

BlackRock Income Fund

Investor A Shares | BMSAX

Semi-Annual Shareholder Report — March 31, 2025

BMSAX-03/25-SAR

BlackRock Income Fund

Investor C Shares | BMSCX

Semi-Annual Shareholder Report — March 31, 2025

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Class name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Investor C Shares	$81	1.62%^{Footnote Reference(a)}

Footnote	Description
Footnote^(a)	Annualized.

Fund performance

Average annual total returns

Average Annual Total Returns	6-Month Total Returns	1 Year	5 years	10 Years
Investor C Shares ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.69%	5.34%	3.86%	2.71%
Investor C Shares (with sales charge)........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.30)	4.34	3.86	2.71
Bloomberg U.S. Universal Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.15)	5.24	0.32	1.83
Customized Reference Benchmark........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.92	7.57	5.66	4.12

Assuming maximum sales charges. Average annual total returns with and without sales charges reflect reductions for distribution and service fees.

Key Fund statistics

Net Assets........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	$1,167,786,636
Number of Portfolio Holdings........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	2,015
Portfolio Turnover Rate........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	156%

What did the Fund invest in?

(as of March 31, 2025)

Portfolio composition

Credit quality allocation

Investment Type	Percent of Total Investments^{Footnote Reference(a)}
Corporate Bonds........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	39.0%
Asset-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	25.4
U.S. Government Sponsored Agency Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	14.0
Floating Rate Loan Interests........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	13.0
Foreign Government Obligations........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	3.2
Investment Companies........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	3.1
Foreign Agency Obligations........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.8
Non-Agency Mortgage-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.7
Preferred Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.6
Common Stocks........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1
Other^{Footnote Reference(b)}........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1

Credit Rating^{Footnote Reference(c)}	Percent of Total Investments^{Footnote Reference(a)}
AAA/Aaa^{Footnote Reference(d)}........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	30.8%
AA/Aa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	2.4
A........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	10.9
BBB/Baa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	22.3
BB/Ba........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	13.5
B........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	11.7
CCC/Caa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.6
CC/Ca........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1
N/R........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	6.7

Footnote	Description
Footnote^(a)	Excludes short-term securities, short investments and options, if any.
Footnote^(b)	Ten largest investment types are presented. Additional investment types are found in Other.
Footnote^(c)	For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.
Footnote^(d)	The investment adviser evaluates the credit quality of unrated investments based upon certain factors including, but not limited to, credit ratings for similar investments and financial analysis of sectors, individual investments and/or issuers. Using this approach, the investment adviser has deemed unrated U.S. Government Sponsored Agency Securities and U.S. Treasury Obligations to be of similar credit quality as investments rated AAA/Aaa.

Additional information

BlackRock Income Fund

Investor C Shares | BMSCX

Semi-Annual Shareholder Report — March 31, 2025

BMSCX-03/25-SAR

BlackRock Income Fund

Class K Shares | BMSKX

Semi-Annual Shareholder Report — March 31, 2025

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Class name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class K Shares	$29	0.57%^{Footnote Reference(a)}

Footnote	Description
Footnote^(a)	Annualized.

Fund performance

Average annual total returns

Average Annual Total Returns	6-Month Total Returns	1 Year	5 years	10 Years
Class K Shares ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.21%	6.45%	4.93%	3.63%
Bloomberg U.S. Universal Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.15)	5.24	0.32	1.83
Customized Reference Benchmark........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.92	7.57	5.66	4.12

Performance shown prior to the Class K Shares inception date of August 1, 2016 is that of Institutional Shares. The performance of Class K Shares would be substantially similar to Institutional Shares because Class K Shares and Institutional Shares invest in the same portfolio of securities and performance would only differ to the extent that Class K Shares and Institutional Shares have different expenses. The actual returns of Class K Shares would have been higher than those of the Institutional Shares because Class K Shares have lower expenses than the Institutional Shares.

Key Fund statistics

Net Assets........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	$1,167,786,636
Number of Portfolio Holdings........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	2,015
Portfolio Turnover Rate........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	156%

What did the Fund invest in?

(as of March 31, 2025)

Portfolio composition

Credit quality allocation

Investment Type	Percent of Total Investments^{Footnote Reference(a)}
Corporate Bonds........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	39.0%
Asset-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	25.4
U.S. Government Sponsored Agency Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	14.0
Floating Rate Loan Interests........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	13.0
Foreign Government Obligations........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	3.2
Investment Companies........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	3.1
Foreign Agency Obligations........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.8
Non-Agency Mortgage-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.7
Preferred Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.6
Common Stocks........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1
Other^{Footnote Reference(b)}........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1

Credit Rating^{Footnote Reference(c)}	Percent of Total Investments^{Footnote Reference(a)}
AAA/Aaa^{Footnote Reference(d)}........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	30.8%
AA/Aa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	2.4
A........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	10.9
BBB/Baa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	22.3
BB/Ba........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	13.5
B........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	11.7
CCC/Caa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.6
CC/Ca........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1
N/R........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	6.7

Footnote	Description
Footnote^(a)	Excludes short-term securities, short investments and options, if any.
Footnote^(b)	Ten largest investment types are presented. Additional investment types are found in Other.
Footnote^(c)	For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.
Footnote^(d)	The investment adviser evaluates the credit quality of unrated investments based upon certain factors including, but not limited to, credit ratings for similar investments and financial analysis of sectors, individual investments and/or issuers. Using this approach, the investment adviser has deemed unrated U.S. Government Sponsored Agency Securities and U.S. Treasury Obligations to be of similar credit quality as investments rated AAA/Aaa.

Additional information

BlackRock Income Fund

Class K Shares | BMSKX

Semi-Annual Shareholder Report — March 31, 2025

BMSKX-03/25-SAR

BlackRock Low Duration Bond Portfolio

Institutional Shares | BFMSX

Semi-Annual Shareholder Report — March 31, 2025

This semi-annual shareholder report contains important information about BlackRock Low Duration Bond Portfolio (the “Fund”) for the period of October 1, 2024 to March 31, 2025.You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441-7762.

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Class name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Institutional Shares	$20	0.40%^{Footnote Reference(a)}

Footnote	Description
Footnote^(a)	Annualized.

Fund performance

Average annual total returns

Average Annual Total Returns	6-Month Total Returns	1 Year	5 years	10 Years
Institutional Shares ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.57%	6.01%	2.77%	2.03%
Bloomberg U.S. Aggregate Bond Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.37)	4.88	(0.40)	1.46
ICE BofA 1-3 Year U.S. Corporate & Government Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.62	5.65	1.60	1.75

On September 17, 2018, the Fund acquired all of the assets, subject to the liabilities, of BlackRock Low Duration Bond Portfolio (the “Predecessor Fund”), a series of BlackRock Funds II, through a tax-free reorganization (the “Reorganization”). The Predecessor Fund is the performance and accounting survivor of the Reorganization.

On December 1, 2023, the Fund began to compare its performance to the standard pricing time of the ICE BofA 1-3 Year US Corporate & Government Index (the “Index”). Index data prior to March 1, 2021 is for the Index’s standard pricing time of 3pm. Index data from March 1, 2021 through November 30, 2023 is for a custom 4pm pricing variant of the Index. Index returns beginning on December 1, 2023 reflect the Index’s new standard pricing time of 4pm. The change of the Index’s standard pricing time from 3pm to 4pm resulted in the discontinuation of the custom 4pm pricing variant used from March 1, 2021 through November 30, 2023.

Key Fund statistics

Net Assets........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	$3,656,141,202
Number of Portfolio Holdings........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1,618
Portfolio Turnover Rate........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	112%

What did the Fund invest in?

(as of March 31, 2025)

Portfolio composition

Credit quality allocation

Investment Type	Percent of Total Investments^{Footnote Reference(a)}
Corporate Bonds........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	44.3%
U.S. Treasury Obligations........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	19.8
Non-Agency Mortgage-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	15.1
Asset-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	13.2
U.S. Government Sponsored Agency Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	6.5
Foreign Agency Obligations........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.0
Municipal Bonds........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1

Credit Rating^{Footnote Reference(b)}	Percent of Total Investments^{Footnote Reference(a)}
AAA/Aaa^{Footnote Reference(c)}........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	45.2%
AA/Aa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	2.9
A........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	14.7
BBB/Baa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	22.6
BB/Ba........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	3.2
B........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	3.1
CCC/Caa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(d)}
D........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(d)}
N/R........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	8.3

Footnote	Description
Footnote^(a)	Excludes short-term securities.
Footnote^(b)	For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.
Footnote^(c)	The investment adviser evaluates the credit quality of unrated investments based upon certain factors including, but not limited to, credit ratings for similar investments and financial analysis of sectors, individual investments and/or issuers. Using this approach, the investment adviser has deemed unrated U.S. Government Sponsored Agency Securities and U.S. Treasury Obligations to be of similar credit quality as investments rated AAA/Aaa.
Footnote^(d)	Rounds to less than 0.1%.

Additional information

The Fund is not sponsored, endorsed, issued, sold, or promoted by Bloomberg Index Services Limited, ICE Data Indices, LLC, and their respective affiliates, nor do these companies make any representation regarding the advisability of investing in the Fund. BlackRock is not affiliated with the company listed above.

BlackRock Low Duration Bond Portfolio

Institutional Shares | BFMSX

Semi-Annual Shareholder Report — March 31, 2025

BFMSX-03/25-SAR

BlackRock Low Duration Bond Portfolio

Investor A Shares | BLDAX

Semi-Annual Shareholder Report — March 31, 2025

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Class name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Investor A Shares	$33	0.65%^{Footnote Reference(a)}

Footnote	Description
Footnote^(a)	Annualized.

Fund performance

Average annual total returns

Average Annual Total Returns	6-Month Total Returns	1 Year	5 years	10 Years
Investor A Shares ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.55%	5.75%	2.51%	1.77%
Investor A Shares (with sales charge)........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.73)	3.37	2.04	1.54
Bloomberg U.S. Aggregate Bond Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.37)	4.88	(0.40)	1.46
ICE BofA 1-3 Year U.S. Corporate & Government Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.62	5.65	1.60	1.75

Assuming maximum sales charges. Average annual total returns with and without sales charges reflect reductions for service fees.

Key Fund statistics

Net Assets........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	$3,656,141,202
Number of Portfolio Holdings........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1,618
Portfolio Turnover Rate........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	112%

What did the Fund invest in?

(as of March 31, 2025)

Portfolio composition

Credit quality allocation

Investment Type	Percent of Total Investments^{Footnote Reference(a)}
Corporate Bonds........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	44.3%
U.S. Treasury Obligations........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	19.8
Non-Agency Mortgage-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	15.1
Asset-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	13.2
U.S. Government Sponsored Agency Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	6.5
Foreign Agency Obligations........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.0
Municipal Bonds........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1

Credit Rating^{Footnote Reference(b)}	Percent of Total Investments^{Footnote Reference(a)}
AAA/Aaa^{Footnote Reference(c)}........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	45.2%
AA/Aa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	2.9
A........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	14.7
BBB/Baa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	22.6
BB/Ba........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	3.2
B........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	3.1
CCC/Caa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(d)}
D........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(d)}
N/R........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	8.3

Footnote	Description
Footnote^(a)	Excludes short-term securities.
Footnote^(b)	For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.
Footnote^(c)	The investment adviser evaluates the credit quality of unrated investments based upon certain factors including, but not limited to, credit ratings for similar investments and financial analysis of sectors, individual investments and/or issuers. Using this approach, the investment adviser has deemed unrated U.S. Government Sponsored Agency Securities and U.S. Treasury Obligations to be of similar credit quality as investments rated AAA/Aaa.
Footnote^(d)	Rounds to less than 0.1%.

Additional information

BlackRock Low Duration Bond Portfolio

Investor A Shares | BLDAX

Semi-Annual Shareholder Report — March 31, 2025

BLDAX-03/25-SAR

BlackRock Low Duration Bond Portfolio

Investor A1 Shares | CMGAX

Semi-Annual Shareholder Report — March 31, 2025

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Class name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Investor A1 Shares	$25	0.50%^{Footnote Reference(a)}

Footnote	Description
Footnote^(a)	Annualized.

Fund performance

Average annual total returns

Average Annual Total Returns	6-Month Total Returns	1 Year	5 years	10 Years
Investor A1 Shares ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.63%	5.91%	2.69%	1.93%
Bloomberg U.S. Aggregate Bond Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.37)	4.88	(0.40)	1.46
ICE BofA 1-3 Year U.S. Corporate & Government Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.62	5.65	1.60	1.75

Average annual total returns reflect reductions for service fees.

Key Fund statistics

Net Assets........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	$3,656,141,202
Number of Portfolio Holdings........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1,618
Portfolio Turnover Rate........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	112%

What did the Fund invest in?

(as of March 31, 2025)

Portfolio composition

Credit quality allocation

Investment Type	Percent of Total Investments^{Footnote Reference(a)}
Corporate Bonds........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	44.3%
U.S. Treasury Obligations........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	19.8
Non-Agency Mortgage-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	15.1
Asset-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	13.2
U.S. Government Sponsored Agency Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	6.5
Foreign Agency Obligations........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.0
Municipal Bonds........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1

Credit Rating^{Footnote Reference(b)}	Percent of Total Investments^{Footnote Reference(a)}
AAA/Aaa^{Footnote Reference(c)}........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	45.2%
AA/Aa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	2.9
A........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	14.7
BBB/Baa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	22.6
BB/Ba........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	3.2
B........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	3.1
CCC/Caa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(d)}
D........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(d)}
N/R........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	8.3

Footnote	Description
Footnote^(a)	Excludes short-term securities.
Footnote^(b)	For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.
Footnote^(c)	The investment adviser evaluates the credit quality of unrated investments based upon certain factors including, but not limited to, credit ratings for similar investments and financial analysis of sectors, individual investments and/or issuers. Using this approach, the investment adviser has deemed unrated U.S. Government Sponsored Agency Securities and U.S. Treasury Obligations to be of similar credit quality as investments rated AAA/Aaa.
Footnote^(d)	Rounds to less than 0.1%.

Additional information

BlackRock Low Duration Bond Portfolio

Investor A1 Shares | CMGAX

Semi-Annual Shareholder Report — March 31, 2025

CMGAX-03/25-SAR

BlackRock Low Duration Bond Portfolio

Investor C Shares | BLDCX

Semi-Annual Shareholder Report — March 31, 2025

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Class name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Investor C Shares	$70	1.40%^{Footnote Reference(a)}

Footnote	Description
Footnote^(a)	Annualized.

Fund performance

Average annual total returns

Average Annual Total Returns	6-Month Total Returns	1 Year	5 years	10 Years
Investor C Shares ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.18%	4.96%	1.77%	1.16%
Investor C Shares (with sales charge)........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.18	3.96	1.77	1.16
Bloomberg U.S. Aggregate Bond Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.37)	4.88	(0.40)	1.46
ICE BofA 1-3 Year U.S. Corporate & Government Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.62	5.65	1.60	1.75

Assuming maximum sales charges. Average annual total returns with and without sales charges reflect reductions for distribution and service fees.

Key Fund statistics

Net Assets........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	$3,656,141,202
Number of Portfolio Holdings........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1,618
Portfolio Turnover Rate........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	112%

What did the Fund invest in?

(as of March 31, 2025)

Portfolio composition

Credit quality allocation

Investment Type	Percent of Total Investments^{Footnote Reference(a)}
Corporate Bonds........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	44.3%
U.S. Treasury Obligations........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	19.8
Non-Agency Mortgage-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	15.1
Asset-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	13.2
U.S. Government Sponsored Agency Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	6.5
Foreign Agency Obligations........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.0
Municipal Bonds........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1

Credit Rating^{Footnote Reference(b)}	Percent of Total Investments^{Footnote Reference(a)}
AAA/Aaa^{Footnote Reference(c)}........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	45.2%
AA/Aa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	2.9
A........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	14.7
BBB/Baa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	22.6
BB/Ba........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	3.2
B........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	3.1
CCC/Caa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(d)}
D........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(d)}
N/R........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	8.3

Footnote	Description
Footnote^(a)	Excludes short-term securities.
Footnote^(b)	For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.
Footnote^(c)	The investment adviser evaluates the credit quality of unrated investments based upon certain factors including, but not limited to, credit ratings for similar investments and financial analysis of sectors, individual investments and/or issuers. Using this approach, the investment adviser has deemed unrated U.S. Government Sponsored Agency Securities and U.S. Treasury Obligations to be of similar credit quality as investments rated AAA/Aaa.
Footnote^(d)	Rounds to less than 0.1%.

Additional information

BlackRock Low Duration Bond Portfolio

Investor C Shares | BLDCX

Semi-Annual Shareholder Report — March 31, 2025

BLDCX-03/25-SAR

BlackRock Low Duration Bond Portfolio

Class K Shares | CLDBX

Semi-Annual Shareholder Report — March 31, 2025

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Class name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class K Shares	$18	0.35%^{Footnote Reference(a)}

Footnote	Description
Footnote^(a)	Annualized.

Fund performance

Average annual total returns

Average Annual Total Returns	6-Month Total Returns	1 Year	5 years	10 Years
Class K Shares ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.70%	6.07%	2.84%	2.09%
Bloomberg U.S. Aggregate Bond Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.37)	4.88	(0.40)	1.46
ICE BofA 1-3 Year U.S. Corporate & Government Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.62	5.65	1.60	1.75

Key Fund statistics

Net Assets........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	$3,656,141,202
Number of Portfolio Holdings........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1,618
Portfolio Turnover Rate........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	112%

What did the Fund invest in?

(as of March 31, 2025)

Portfolio composition

Credit quality allocation

Investment Type	Percent of Total Investments^{Footnote Reference(a)}
Corporate Bonds........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	44.3%
U.S. Treasury Obligations........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	19.8
Non-Agency Mortgage-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	15.1
Asset-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	13.2
U.S. Government Sponsored Agency Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	6.5
Foreign Agency Obligations........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.0
Municipal Bonds........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1

Credit Rating^{Footnote Reference(b)}	Percent of Total Investments^{Footnote Reference(a)}
AAA/Aaa^{Footnote Reference(c)}........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	45.2%
AA/Aa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	2.9
A........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	14.7
BBB/Baa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	22.6
BB/Ba........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	3.2
B........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	3.1
CCC/Caa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(d)}
D........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(d)}
N/R........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	8.3

Footnote	Description
Footnote^(a)	Excludes short-term securities.
Footnote^(b)	For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.
Footnote^(c)	The investment adviser evaluates the credit quality of unrated investments based upon certain factors including, but not limited to, credit ratings for similar investments and financial analysis of sectors, individual investments and/or issuers. Using this approach, the investment adviser has deemed unrated U.S. Government Sponsored Agency Securities and U.S. Treasury Obligations to be of similar credit quality as investments rated AAA/Aaa.
Footnote^(d)	Rounds to less than 0.1%.

Additional information

BlackRock Low Duration Bond Portfolio

Class K Shares | CLDBX

Semi-Annual Shareholder Report — March 31, 2025

CLDBX-03/25-SAR

BlackRock Low Duration Bond Portfolio

Class R Shares | BLDPX

Semi-Annual Shareholder Report — March 31, 2025

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Class name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class R Shares	$45	0.90%^{Footnote Reference(a)}

Footnote	Description
Footnote^(a)	Annualized.

Fund performance

Average annual total returns

Average Annual Total Returns	6-Month Total Returns	1 Year	5 years	10 Years
Class R Shares ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.43%	5.49%	2.28%	1.52%
Bloomberg U.S. Aggregate Bond Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.37)	4.88	(0.40)	1.46
ICE BofA 1-3 Year U.S. Corporate & Government Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.62	5.65	1.60	1.75

Average annual total returns reflect reductions for distribution and service fees.

Key Fund statistics

Net Assets........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	$3,656,141,202
Number of Portfolio Holdings........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1,618
Portfolio Turnover Rate........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	112%

What did the Fund invest in?

(as of March 31, 2025)

Portfolio composition

Credit quality allocation

Investment Type	Percent of Total Investments^{Footnote Reference(a)}
Corporate Bonds........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	44.3%
U.S. Treasury Obligations........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	19.8
Non-Agency Mortgage-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	15.1
Asset-Backed Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	13.2
U.S. Government Sponsored Agency Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	6.5
Foreign Agency Obligations........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.0
Municipal Bonds........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1

Credit Rating^{Footnote Reference(b)}	Percent of Total Investments^{Footnote Reference(a)}
AAA/Aaa^{Footnote Reference(c)}........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	45.2%
AA/Aa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	2.9
A........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	14.7
BBB/Baa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	22.6
BB/Ba........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	3.2
B........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	3.1
CCC/Caa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(d)}
D........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.0^{Footnote Reference(d)}
N/R........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	8.3

Footnote	Description
Footnote^(a)	Excludes short-term securities.
Footnote^(b)	For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.
Footnote^(c)	The investment adviser evaluates the credit quality of unrated investments based upon certain factors including, but not limited to, credit ratings for similar investments and financial analysis of sectors, individual investments and/or issuers. Using this approach, the investment adviser has deemed unrated U.S. Government Sponsored Agency Securities and U.S. Treasury Obligations to be of similar credit quality as investments rated AAA/Aaa.
Footnote^(d)	Rounds to less than 0.1%.

Additional information

BlackRock Low Duration Bond Portfolio

Class R Shares | BLDPX

Semi-Annual Shareholder Report — March 31, 2025

BLDPX-03/25-SAR

BlackRock Sustainable High Yield Bond Fund

Institutional Shares | BSIHX

Semi-Annual Shareholder Report — March 31, 2025

This semi-annual shareholder report contains important information about BlackRock Sustainable High Yield Bond Fund (the “Fund”) for the period of October 1, 2024 to March 31, 2025.You can find additional information about the Fund at blackrock.com/fundreports. You can also request this information by contacting us at (800) 441-7762.

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Class name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Institutional Shares	$29	0.58%^{Footnote Reference(a)}

Footnote	Description
Footnote^(a)	Annualized.

Fund performance

Average annual total returns

Average Annual Total Returns	6-Month Total Returns	1 Year	Since Fund Inception
Institutional Shares ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.83%	6.84%	2.43%
Bloomberg U.S. Universal Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.15)	5.24	(1.11)
Bloomberg U.S. Corporate High Yield 2% Issuer Capped Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.18	7.69	3.01

The Fund commenced operations on July 22, 2021.

Key Fund statistics

Net Assets........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	$44,765,792
Number of Portfolio Holdings........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	522
Portfolio Turnover Rate........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	26%

What did the Fund invest in?

(as of March 31, 2025)

Portfolio composition

Credit quality allocation

Investment Type	Percent of Total Investments^{Footnote Reference(a)}
Corporate Bonds........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	91.6%
Floating Rate Loan Interests........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	7.4
Preferred Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.7
Common Stocks........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.2
Fixed Rate Loan Interests........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1

Credit Rating^{Footnote Reference(b)}	Percent of Total Investments^{Footnote Reference(a)}
BBB/Baa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	2.2%
BB/Ba........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	39.4
B........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	46.7
CCC/Caa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	11.3
N/R........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.4

Footnote	Description
Footnote^(a)	Excludes short-term securities.
Footnote^(b)	For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.

Additional information

BlackRock Sustainable High Yield Bond Fund

Institutional Shares | BSIHX

Semi-Annual Shareholder Report — March 31, 2025

BSIHX-03/25-SAR

BlackRock Sustainable High Yield Bond Fund

Investor A Shares | BSHAX

Semi-Annual Shareholder Report — March 31, 2025

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Class name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Investor A Shares	$42	0.83%^{Footnote Reference(a)}

Footnote	Description
Footnote^(a)	Annualized.

Fund performance

Average annual total returns

Average Annual Total Returns	6-Month Total Returns	1 Year	Since Fund Inception
Investor A Shares ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.70%	6.57%	2.17%
Investor A Shares (with sales charge)........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(3.33)	2.31	1.05
Bloomberg U.S. Universal Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.15)	5.24	(1.11)
Bloomberg U.S. Corporate High Yield 2% Issuer Capped Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.18	7.69	3.01

Assuming maximum sales charges. Average annual total returns with and without sales charges reflect reductions for service fees.

The Fund commenced operations on July 22, 2021.

Key Fund statistics

Net Assets........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	$44,765,792
Number of Portfolio Holdings........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	522
Portfolio Turnover Rate........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	26%

What did the Fund invest in?

(as of March 31, 2025)

Portfolio composition

Credit quality allocation

Investment Type	Percent of Total Investments^{Footnote Reference(a)}
Corporate Bonds........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	91.6%
Floating Rate Loan Interests........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	7.4
Preferred Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.7
Common Stocks........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.2
Fixed Rate Loan Interests........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1

Credit Rating^{Footnote Reference(b)}	Percent of Total Investments^{Footnote Reference(a)}
BBB/Baa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	2.2%
BB/Ba........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	39.4
B........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	46.7
CCC/Caa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	11.3
N/R........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.4

Footnote	Description
Footnote^(a)	Excludes short-term securities.
Footnote^(b)	For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.

Additional information

BlackRock Sustainable High Yield Bond Fund

Investor A Shares | BSHAX

Semi-Annual Shareholder Report — March 31, 2025

BSHAX-03/25-SAR

BlackRock Sustainable High Yield Bond Fund

Class K Shares | BSHKX

Semi-Annual Shareholder Report — March 31, 2025

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Class name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class K Shares	$27	0.53%^{Footnote Reference(a)}

Footnote	Description
Footnote^(a)	Annualized.

Fund performance

Average annual total returns

Average Annual Total Returns	6-Month Total Returns	1 Year	Since Fund Inception
Class K Shares ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.85%	6.89%	2.47%
Bloomberg U.S. Universal Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	(0.15)	5.24	(1.11)
Bloomberg U.S. Corporate High Yield 2% Issuer Capped Index........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	1.18	7.69	3.01

The Fund commenced operations on July 22, 2021.

Key Fund statistics

Net Assets........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	$44,765,792
Number of Portfolio Holdings........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	522
Portfolio Turnover Rate........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	26%

What did the Fund invest in?

(as of March 31, 2025)

Portfolio composition

Credit quality allocation

Investment Type	Percent of Total Investments^{Footnote Reference(a)}
Corporate Bonds........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	91.6%
Floating Rate Loan Interests........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	7.4
Preferred Securities........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.7
Common Stocks........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.2
Fixed Rate Loan Interests........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.1

Credit Rating^{Footnote Reference(b)}	Percent of Total Investments^{Footnote Reference(a)}
BBB/Baa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	2.2%
BB/Ba........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	39.4
B........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	46.7
CCC/Caa........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	11.3
N/R........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................	0.4

Footnote	Description
Footnote^(a)	Excludes short-term securities.
Footnote^(b)	For purposes of this report, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service, Inc. if ratings differ. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.

Additional information

BlackRock Sustainable High Yield Bond Fund

Class K Shares | BSHKX

Semi-Annual Shareholder Report — March 31, 2025

BSHKX-03/25-SAR