Tranche Update on BlackRock MuniVest Fund, Inc.'s Equity Buyback Plan announced on September 8, 2022.

BlackRock MuniVest Fund, Inc. is a non-diversified, closed-end management investment company. The Trust's investment objective is to provide shareholders with as high a level of current income exempt from federal income taxes as is consistent with its investment policies and prudent investment management. It seeks to achieve its investment objective by investing at least 80% of an aggregate of the Trust's net assets and the proceeds of any borrowing for investment purposes, in municipal obligations exempt from federal income taxes. The Trust invests in long-term municipal obligations rated investment grade at the time of investment and in long term municipal obligations with maturities of over 10 years at the time of investment. It may invest up to 20% of its total assets in securities rated below investment grade at the time of purchase. It may invest directly in such securities or synthetically through the use of derivatives. Investment advisor of the Fund is BlackRock Advisors, LLC.