BlackRock Basic Value Fund, Inc.

BlackRock Bond Fund, Inc.

BlackRock Total Return Fund

BlackRock Funds^SM

BlackRock Developed Real Estate Index Fund

BlackRock Emerging Markets Equity Strategies Fund

BlackRock Midcap Index Fund

BlackRock MSCI Asia ex Japan Index Fund

BlackRock MSCI World Index Fund

BlackRock Short Obligations Fund

BlackRock Short-Term Inflation-Protected Securities Index Fund

BlackRock Small/Mid Cap Index Fund

BlackRock Total Stock Market Index Fund

BlackRock Funds II

BlackRock Core Bond Portfolio

BlackRock Emerging Markets Flexible Dynamic Bond Portfolio

BlackRock GNMA Portfolio

BlackRock High Yield Bond Portfolio

BlackRock Inflation Protected Bond Portfolio

BlackRock Investment Grade Bond Portfolio

BlackRock LifePath^® Active Retirement Fund

BlackRock LifePath^® Active 2020 Fund

BlackRock LifePath^® Active 2025 Fund

BlackRock LifePath^® Active 2030 Fund

BlackRock LifePath^® Active 2035 Fund

BlackRock LifePath^® Active 2040 Fund

BlackRock LifePath^® Active 2045 Fund

BlackRock LifePath^® Active 2050 Fund

BlackRock LifePath^® Active 2055 Fund

BlackRock Low Duration Bond Portfolio

BlackRock U.S. Government Bond Portfolio

BlackRock Funds III

BlackRock Disciplined International Fund

BlackRock Large Cap Index Fund

BlackRock LifePath^® Index Retirement Fund

BlackRock LifePath^® Index 2020 Fund

BlackRock LifePath^® Index 2025 Fund

BlackRock LifePath^® Index 2030 Fund

BlackRock LifePath^® Index 2035 Fund

BlackRock LifePath^® Index 2040 Fund

BlackRock LifePath^® Index 2045 Fund

BlackRock LifePath^® Index 2050 Fund

BlackRock LifePath^® Index 2055 Fund

BlackRock LifePath^® Index 2060 Fund

BlackRock LifePath^® Retirement Fund

BlackRock LifePath^® 2020 Fund

BlackRock LifePath^® 2025 Fund

BlackRock LifePath^® 2030 Fund

BlackRock LifePath^® 2035 Fund

BlackRock LifePath^® 2040 Fund

BlackRock LifePath^® 2045 Fund

BlackRock LifePath^® 2050 Fund

BlackRock LifePath^® 2055 Fund

BlackRock S&P 500 Index Fund

BlackRock Total International ex U.S. Index Fund

BlackRock U.S. Total Bond Index Fund

BlackRock Index Funds, Inc.

BlackRock International Index Fund

BlackRock Small Cap Index Fund

BlackRock Municipal Bond Fund, Inc.

BlackRock Short-Term Municipal Fund

BlackRock Strategic Global Bond Fund, Inc.

(each, a “Fund” and collectively, the “Funds”)

Supplement dated March 25, 2016

to the Statement of Additional Information of each Fund

Effective immediately, Part II of each Fund’s Statement of Additional Information is amended as follows:

The following is added to the section entitled “Purchase of Shares—Class K Shares” in Part II of each Fund’s Statement of Additional Information:

Class K Shares of the Fund are also available to employees, officers and directors/trustees of BlackRock, Inc. and BlackRock Funds and immediate family members of such persons, if they open an account directly with BlackRock. Eligible individuals who would like to convert existing holdings to Class K Shares must contact BlackRock.

Shareholders should retain this Supplement for future reference.

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