497 1 form.txt FEDERATED MUNICIPAL SECURITIES FUND, INC. Class A Shares Class B Shares Class C Shares Supplement to Statement of Additional Information dated May 31, 2006 Under the section entitled "Securities in Which the Fund Invests" please add the following directly following "Credit Enhancement": TAX-EXEMPT COMMERCIAL PAPER Tax-exempt commercial paper is a tax-exempt issuer's obligation with a maturity of less than nine months. Tax-exempt issuers may issue commercial paper to pay for current expenditures or other permissible activities. Tax-exempt issues may constantly reissue their commercial paper and use the proceeds (or other sources) to repay maturing paper. If the tax-exempt issuer cannot continue to obtain liquidity in this fashion, its commercial paper may default. October 5, 2006 Cusip 313913105 313913204 313913303 35627 (9/06)