BLACKROCK FUNDS III
iShares S&P 500 Index Fund
(the “Fund”)
Supplement dated May 16, 2025 to the Summary Prospectuses and the
Prospectuses of the Fund, each dated April 30, 2025, as amended or supplemented to date
Effective June 30, 2025, the following changes are made to the Fund’s Summary Prospectuses and Prospectuses, as applicable:
The section of the Summary Prospectuses entitled “Key Facts About iShares S&P 500 Index Fund — Portfolio Managers” and the section of the Prospectuses entitled “Fund Overview — Key Facts About iShares S&P 500 Index Fund — Portfolio Managers” are deleted in their entirety and replaced with the following:
| Portfolio Manager | Portfolio Manager of the Master Portfolio Since |
Title | ||
| Jennifer Hsui, CFA | 2016 | Managing Director of BlackRock, Inc | ||
| Matt Waldron, CFA | 2025 | Managing Director of BlackRock, Inc | ||
| Peter Sietsema, CFA | 2025 | Director of BlackRock, Inc | ||
| Steven White | 2025 | Director of BlackRock, Inc |
The section of the Prospectuses entitled “Details About the Fund — How the Fund Invests — About the Portfolio Management Team of the Fund/Master Portfolio” is deleted in its entirety and replaced with the following:
| ABOUT THE PORTFOLIO MANAGEMENT TEAM OF THE FUND/MASTER PORTFOLIO |
| The Master Portfolio is managed by a team of financial professionals. Jennifer Hsui, CFA, Matt Waldron, CFA, Peter Sietsema, CFA, and Steven White and are the portfolio managers and are jointly and primarily responsible for the day-to-day management of the Master Portfolio. Please see “Management of the Fund — Portfolio Managers” for additional information about the portfolio management team. |
The section of the Prospectuses entitled “Management of the Fund — Portfolio Manager Information” is deleted in its entirety and replaced with the following:
Information regarding the portfolio managers of the Master Portfolio is set forth below. Further information regarding the portfolio managers, including other accounts managed, compensation, ownership of Fund shares, and possible conflicts of interest, is available in the Fund’s SAI.
| Portfolio Manager | Primary Role | Since | Title and Recent Biography | |||
| Jennifer Hsui, CFA | Jointly and primarily responsible for the day-to-day management of the Master Portfolio, including setting the Master Portfolio’s overall investment strategy and overseeing the management of the Master Portfolio. | 2016 | Managing Director of BlackRock, Inc. since 2011. | |||
| Matt Waldron, CFA | Jointly and primarily responsible for the day-to-day management of the Master Portfolio, including setting the Master Portfolio’s overall investment strategy and overseeing the management of the Master Portfolio | 2025 | Managing Director of BlackRock, Inc. since 2024; Director of BlackRock, Inc from 2010 to 2024. |
| Portfolio Manager | Primary Role | Since | Title and Recent Biography | |||
| Peter Sietsema, CFA | Jointly and primarily responsible for the day-to-day management of the Master Portfolio, including setting the Master Portfolio’s overall investment strategy and overseeing the management of the Master Portfolio | 2025 | Director of BlackRock, Inc. since 2013. | |||
| Steven White | Jointly and primarily responsible for the day-to-day management of the Master Portfolio, including setting the Master Portfolio’s overall investment strategy and overseeing the management of the Master Portfolio | 2025 | Director of BlackRock, Inc. since 2020. |
| Shareholders should retain this Supplement for future reference. |
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