BlackRock U.S. Government Bond Portfolio Investor A Shares (BlackRock Impact Mortgage Fund) 

This fund aims to generate the highest possible overall return while also providing consistent income and utilizing responsible investment strategies. It achieves this by investing in fixed-income assets that the fund's managers identify as having a beneficial social and/or environmental impact. To accomplish its objective, the fund commits a minimum of 80% of its net assets, plus any capital borrowed for investment, to mortgage-backed debt instruments and other mortgage-linked securities that are issued or guaranteed by the United States government and its agencies.