BlackRock Bond Fund, Inc. BlackRock Total Return Fund	BlackRock Series Fund, Inc. BlackRock High Yield Portfolio BlackRock Total Return Portfolio BlackRock U.S. Government Bond Portfolio
BlackRock FundsSM BlackRock Global Long/Short Credit Fund BlackRock Global Opportunities Portfolio BlackRock Managed Volatility Portfolio BlackRock Multi-Asset Real Return Fund BlackRock Real Estate Securities Fund BlackRock Strategic Risk Allocation Fund	BlackRock Variable Series Funds, Inc. BlackRock High Yield V.I. Fund BlackRock Managed Volatility V.I. Fund BlackRock Total Return V.I. Fund BlackRock U.S. Government Bond V.I. Fund
BlackRock Funds II BlackRock Core Bond Portfolio BlackRock Emerging Markets Flexible Dynamic Bond Portfolio BlackRock Floating Rate Income Portfolio BlackRock GNMA Portfolio BlackRock High Yield Bond Portfolio BlackRock Inflation Protected Bond Portfolio BlackRock Investment Grade Bond Portfolio BlackRock Low Duration Bond Portfolio BlackRock Secured Credit Portfolio BlackRock Strategic Income Opportunities Portfolio BlackRock U.S. Government Bond Portfolio	BlackRock World Income Fund, Inc. Managed Account Series BlackRock U.S. Mortgage Portfolio

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

Supplement dated June 30, 2014 to the Prospectus and Statement of Additional Information (“SAI”) of each Fund

Effective July 1, 2014, the sub-advisory agreements between BlackRock Advisors, LLC (“BlackRock”) and BlackRock Financial Management, Inc. (“BFM”) with respect to the Funds expired or were terminated, as applicable. BlackRock will remain as the investment adviser to each Fund and will provide investment advisory services to each Fund pursuant to the applicable investment advisory agreement currently in effect with BlackRock. To the extent a Fund has other sub-advisory arrangements in place, they will not be impacted by this change. The same portfolio management teams will continue to manage the Funds and there will be no change in the advisory fee rates payable by the Funds to BlackRock as a result of the expiration or termination of the sub-advisory agreements.

References in each Fund’s prospectus and SAI to BFM currently serving as a sub-adviser to the Fund are hereby deleted. For information about the investment advisory arrangements for the Fund and BlackRock, see “Management of the Fund(s) — BlackRock” in the Fund’s prospectus.

For purposes of this supplement and where applicable, the term “Fund” may refer to the master portfolio in which a Fund invests its assets.

Shareholders should retain this Supplement for future reference.

PRSAI-BFM-0614SUP