BlackRock Muniassets Fund May Offer, From Time To Time, In One Or More Offerings, Up To 17M Shares Of Common Stock

PRELIMINARY BASE PROSPECTUS

17,000,000 Shares

BlackRock MuniAssets Fund, Inc.

Shares of Common Stock

Rights to Purchase Shares of Common Stock

BlackRock MuniAssets Fund, Inc. (the "Fund," "we," "us" or "our") is a diversified, closed-end management investment company. The Fund's investment objective is to provide high current income exempt from U.S. federal income taxes by investing primarily in a portfolio of medium- to lower-grade or unrated municipal obligations the interest on which, in the opinion of bond counsel to the issuer, is exempt from U.S. federal income taxes.

We may offer, from time to time, in one or more offerings, up to 17,000,000 shares of our common stock, par value $0.10 per share ("common shares"). We may also offer subscription rights to purchase our common shares. Common shares may be offered at prices and on terms to be set forth in one or more supplements to this Prospectus (each, a "Prospectus Supplement"). You should read this Prospectus and the applicable Prospectus Supplement carefully before you invest in our common shares.

Our common shares may be offered directly to one or more purchasers, including existing shareholders in a rights offering, through agents designated from time to time by us, or to or through underwriters or dealers. The Prospectus Supplement relating to the offering will identify any agents or underwriters involved in the sale of our common shares, and will set forth any applicable purchase price, fee, commission or discount arrangement between us and our agents or underwriters, or among our underwriters, or the basis upon which such amount may be calculated. The Prospectus Supplement relating to any offering of rights will set forth the number of common shares issuable upon the exercise of each right (or number of rights) and the other terms of such rights offering. We may not sell any of our common shares through agents, underwriters or dealers without delivery of a Prospectus Supplement describing the method and terms of the particular offering of our common shares.