UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM N-CSR

CERTIFIED SHAREHOLDER REPORT OF REGISTERED MANAGEMENT INVESTMENT COMPANIES

Investment Company Act file number: 811-23341

Name and address of agent for service: John M. Perlowski, Chief Executive Officer, BlackRock Funds IV,
50 Hudson Yards, New York, NY 10001

Registrant’s telephone number, including area code: (800) 441-7762

Date of fiscal year end: 12/31/2023

Date of reporting period: 06/30/2023

Item 1 – Report to Stockholders

(a) The Report to Shareholders is attached herewith.

BlackRock Funds IV

BlackRock Funds V

Table of Contents

Investment Objective

BlackRock Systematic Multi-Strategy Fund’s (the “Fund”) investment objective is to seek total return comprised of current income and capital appreciation.

Portfolio Management Commentary

How did the Fund perform?

For the six-month period ended June 30, 2023, all of the Fund’s share classes underperformed both its primary benchmark, the ICE BofA 3-Month U.S. Treasury Bill Index and its secondary benchmark, the Bloomberg U.S. Aggregate Bond Index.

What factors influenced performance?

The main detractor from the Fund’s performance during the period was the defensive equity long/short strategy. Given the strategy’s unique credit-oriented approach, it tends to outperform in extended periods of heightened volatility and market stress and is intended to provide downside protection for the portfolio during sell-offs. Equity indices rallied broadly during the period; performance beneath the surface has mainly been pro-cyclical in nature, signaling that equity markets are not pricing in recession fears despite persistent inflation and strong economic data. The bond market continued to show mixed signals, becoming increasingly inverted but with high-yield spreads remaining well below typical recession levels. These factors, coupled with muted equity volatility and dispersion, challenged the defensive equity long/short strategy.

Conversely, the most significant contributor to the Fund’s relative performance was the directional asset allocation (“DAA”) strategy. The DAA strategy involves taking long-only fixed-income asset exposure to capture market upside, seeking to balance credit and interest rate risks, and it has performed well year-to-date as broad market indices have been positive. The largest gains came from carry strategies across the Fund’s fixed-income holdings, as the higher level of interest rates led to more attractive opportunities for income generation. In particular, the strategy benefited from duration exposure in January 2023 and March 2023 as interest rates fell sharply. Despite negative performance for U.S. Treasuries and the Bloomberg U.S. Aggregate Bond Index in the second quarter of 2023, the DAA strategy drove gains in the portfolio, with strong performance from securitized credit and investment-grade credit exposure.

Describe recent portfolio activity.

The Fund continued to apply its systematic investment approach, which combines asset allocation, defensive equity long/short alpha, and macro strategies across diversified asset classes. The Fund seeks to provide diversified alpha sources for balanced, consistent returns over time through various market conditions.

During the reporting period, the Fund increased its allocations to investment-grade credit and kept duration levels toward the low end of historical ranges to be well-positioned against further fixed income and interest rate volatility. Exposure to securitized credit increased gradually to capitalize on the sustained risk-on moves in the financial markets. The Fund’s regime indicator signaled recession risk starting in the fourth quarter of 2022, and the Fund reduced its risk asset exposure during the period in response.

The Fund continued to use leveraged strategies, which involve holding cash in order to back investments in to-be-announced mortgage derivative securities. The use of these and other derivatives had a positive impact on performance for the reporting period. Despite having a reported cash position exceeding 5%, the Fund’s investable cash position is negative due to unsettled forward transactions on derivatives and did not have a material impact on performance.

Describe portfolio positioning at period end.

The Fund ended the reporting period with positioning that reflected a cautious outlook given persistent core inflation and strong economic data that signal the potential for more restrictive monetary policy despite the Fed’s pause in June 2023.

In particular, the Fund continued to prefer higher allocations to high-quality assets, including investment-grade bonds and mortgages. The Fund sought to take advantage of elevated yields to get high-quality income into the portfolio. Lower allocations to high-risk, high-beta asset classes like high yield and dividend equities remained in place, as valuations appeared elevated with risk skewed to the downside. Alpha-focused strategies continue to seek to take advantage of dispersion within macro rates and equities. As uncertainty continues to grow, the opportunity set for these strategies increases.

The views expressed reflect the opinions of BlackRock as of the date of this report and are subject to change based on changes in market, economic or other conditions. These views are not intended to be a forecast of future events and are no guarantee of future results.

Performance

N/A — Not applicable as the share class and index do not have a sales charge.

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.

Expense Example

See “Disclosure of Expenses” for further information on how expenses were calculated.

Portfolio Information

Investment Objective

BlackRock Sustainable Emerging Markets Bond Fund’s (the “Fund”) investment objective is to seek total return, while seeking to maintain certain environmental, governance and social (“ESG”) characteristics, climate risk exposure and climate opportunities relative to the Fund’s benchmark.

Portfolio Management Commentary

How did the Fund perform?

For the six-month period ended June 30, 2023, all of the Fund’s share classes outperformed both its primary benchmark, the J.P. Morgan Emerging Markets Bond Index (“EMBI”) Global Diversified Index and its secondary benchmark, the J.P. Morgan ESG EMBI Global Diversified Index.

What factors influenced performance?

The Fund used short positions in U.S. Treasury futures to manage interest rate risk, which helped performance at a time of rising rates. An overweight in Argentina was also a large contributor, as the potential for a shift to a more centrist government in the upcoming general elections provided reason for optimism in the country. An overweight position in Ukraine made a notable contribution, as well. The bonds rallied due to several factors, the most significant of which was better-than-expected GDP growth. Positioning in emerging market currencies, which the Fund achieved through the use of derivatives, was a further contributor. The Fund’s overweight in Ghana was an additional positive. The country secured a $3 billion deal from the International Monetary Fund after creditors agreed to a debt restructuring.

The Fund’s overweight in Egypt was the largest detractor. The bonds declined in price in the absence of news showing progress on the country’s privatization plan. An overweight in Ecuador also detracted. The nation’s bonds sold off when the rejection of a referendum signaled a low level of confidence in President Lasso’s government. An underweight in Turkey further detracted, as the appointment of market-friendly policymakers raised hopes for a possible return to monetary orthodoxy in the inflation-embattled nation. A zero weighting in Nigeria detracted, as well. The Fund’s cash position did not have a material impact on performance.

Describe recent portfolio activity.

At the start of the year 2023, the investment adviser moved from an underweight to duration to an overweight, which helped performance as yields subsequently fell. (Duration is a measure of interest-rate sensitivity.) Given its constructive view on risk, the investment adviser added to overweight positions in lower-rated issuers such as South Africa and Colombia. It also increased the extent of the Fund’s underweight position in Brazil and shifted to an underweight in Poland. It added some currency positions, as well.

Toward the end of the reporting period, the investment adviser decreased the portfolio’s overall risk profile by reducing its allocation to B rated issues and adding to higher-quality high yield bonds. It selectively allocated to new issues, with a focus on fundamentals. Late in the reporting period, it added to positions in the distressed sovereign debt of Argentina and Ukraine on the belief the bonds can continue to benefit from increasing investor risk appetites. In addition, the upcoming Argentine election in October 2023 and optimism regarding the possibility of peace talks in Ukraine represent potential catalysts for the respective countries.

Describe portfolio positioning at period end.

Panama, Colombia, Oman and Romania were the Fund’s largest overweights, while Turkey Malaysia, China and Philippines were its most notable underweights. The Fund’s beta (risk profile) was equal to the primary benchmark, and its duration was 0.9 years below the index.

The views expressed reflect the opinions of BlackRock as of the date of this report and are subject to change based on changes in market, economic or other conditions. These views are not intended to be a forecast of future events and are no guarantee of future results.

Performance

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.

Expense Example

See “Disclosure of Expenses” for further information on how expenses were calculated.

Portfolio Information

About Fund Performance

Institutional Shares and Class K Shares are not subject to any sales charge. These shares bear no ongoing distribution or service fees and are available only to certain eligible investors. BlackRock Systematic Multi-Strategy Fund’s Class K Shares performance shown prior to the Class K Shares inception date of September 29, 2020 is that of Institutional Shares. The performance of BlackRock Systematic Multi-Strategy Fund’s 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 for BlackRock Systematic Multi-Strategy Fund would have been higher than those of the Institutional Shares because Class K Shares have lower expenses than the Institutional Shares.

Investor A Shares (available only in BlackRock Systematic Multi-Strategy Fund) are subject to a maximum initial sales charge (front-end load) of 4.00% and a service fee of 0.25% per year (but no distribution fee). Certain redemptions of these shares may be subject to a contingent deferred sales charge (“CDSC”) where no initial sales charge was paid at the time of purchase. These shares are generally available through financial intermediaries.

Investor C Shares (available only in BlackRock Systematic Multi-Strategy Fund) are subject to a 1.00% CDSC if redeemed within one year of purchase. In addition, these shares are subject to a distribution fee of 0.75% per year and a service fee of 0.25% per year. These shares are generally available through financial intermediaries. These shares automatically convert to Investor A Shares after approximately eight years.

Past performance is not an indication of future results. Financial markets have experienced extreme volatility and trading in many instruments has been disrupted. These circumstances may continue for an extended period of time and may continue to affect adversely the value and liquidity of each Fund’s investments. As a result, current performance may be lower or higher than the performance data quoted. Refer to blackrock.com to obtain performance data current to the most recent month-end. Performance results do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or the redemption of Fund shares. Figures shown in the performance table(s) assume reinvestment of all distributions, if any, at net asset value (“NAV”) on the ex-dividend date or payable date, as applicable. Investment return and principal value of shares will fluctuate so that shares, when redeemed, may be worth more or less than their original cost. Distributions paid to each class of shares will vary because of the different levels of service, distribution and transfer agency fees applicable to each class, which are deducted from the income available to be paid to shareholders.

BlackRock Advisors, LLC (the “Manager”), each Fund’s investment adviser, has contractually and/or voluntarily agreed to waive and/or reimburse a portion of each Fund’s expenses. Without such waiver(s) and/or reimbursement(s), each Fund’s performance would have been lower. With respect to each Fund’s voluntary waiver(s), if any, the Manager is under no obligation to waive and/or reimburse or to continue waiving and/or reimbursing its fees and such voluntary waiver(s) may be reduced or discontinued at any time. With respect to each Fund’s contractual waiver(s), if any, the Manager is under no obligation to continue waiving and/or reimbursing its fees after the applicable termination date of such agreement. See the Notes to Financial Statements for additional information on waivers and/or reimbursements.

The standardized 30-day yield includes the effects of any waivers and/or reimbursements. The unsubsidized 30-day yield excludes the effects of any waivers and/or reimbursements.

Disclosure of Expenses

Shareholders of each Fund may incur the following charges: (a) transactional expenses, such as sales charges; and (b) operating expenses, including investment advisory fees, service and distribution fees, including 12b-1 fees, acquired fund fees and expenses, and other fund expenses. The expense examples shown (which are based on a hypothetical investment of $1,000 invested at the beginning of the period and held through the end of the period) are intended to assist shareholders both in calculating expenses based on an investment in each Fund and in comparing these expenses with similar costs of investing in other mutual funds.

The expense examples provide information about actual account values and actual expenses. Annualized expense ratios reflect contractual and voluntary fee waivers, if any. In order to estimate the expenses a shareholder paid during the period covered by this report, shareholders can divide their account value by $1,000 and then multiply the result by the number corresponding to their Fund and share class under the heading entitled “Expenses Paid During the Period.”

The expense examples also provide information about hypothetical account values and hypothetical expenses based on a Fund’s actual expense ratio and an assumed rate of return of 5% per year before expenses. In order to assist shareholders in comparing the ongoing expenses of investing in these Funds and other funds, compare the 5% hypothetical examples with the 5% hypothetical examples that appear in shareholder reports of other funds.

The expenses shown in the expense examples are intended to highlight shareholders’ ongoing costs only and do not reflect transactional expenses, such as sales charges, if any. Therefore, the hypothetical examples are useful in comparing ongoing expenses only and will not help shareholders determine the relative total expenses of owning different funds. If these transactional expenses were included, shareholder expenses would have been higher.

Derivative Financial Instruments

The Funds may invest in various derivative financial instruments. These instruments are used to obtain exposure to a security, commodity, index, market, and/or other assets without owning or taking physical custody of securities, commodities and/or other referenced assets or to manage market, equity, credit, interest rate, foreign currency exchange rate, commodity and/or other risks. Derivative financial instruments may give rise to a form of economic leverage and involve risks, including the imperfect correlation between the value of a derivative financial instrument and the underlying asset, possible default of the counterparty to the transaction or illiquidity of the instrument. Pursuant to Rule 18f-4 under the 1940 Act, among other things, the Funds must either use derivative financial instruments with embedded leverage in a limited manner or comply with an outer limit on fund leverage risk based on value-at-risk. The Funds’ successful use of a derivative financial instrument depends on the investment adviser’s ability to predict pertinent market movements accurately, which cannot be assured. The use of these instruments may result in losses greater than if they had not been used, may limit the amount of appreciation a Fund can realize on an investment and/or may result in lower distributions paid to shareholders. The Funds’ investments in these instruments, if any, are discussed in detail in the Notes to Financial Statements.