Under normal circumstances, the Fund invests at least 80% of its Assets in municipal securities, the income from which is exempt from federal income tax. This is a fundamental policy. For purposes of this policy, Assets means net assets, plus the amount of borrowings for investment purposes. Up to 25% of the Fund's Assets may be invested in municipal securities, the interest on which may be subject to the federal alternative minimum tax for individuals. Municipal securities are debt securities issued by or on behalf of states, territories and possessions of the United States, including the District of Columbia, and their respective authorities, political subdivisions, agencies and instrumentalities and other groups with the authority to act for the municipalities, the interest on which is exempt from federal income tax. The securities are issued to raise funds for various public and private purposes. Municipal securities include variable rate demand obligations, variable rate demand preferred securities, short-term municipal notes, tax exempt commercial paper, private activity and industrial development bonds, tax anticipation notes, bond anticipation notes, revenue anticipation notes or other short term notes, private placements and participations in pools of municipal securities. Municipal securities also include instruments evidencing direct ownership of interest payments or principal payments, or both, on municipal securities, such as tender option bonds and participation interests in all or part of specific holdings of municipal obligations, provided that the applicable issuer receives assurances from legal counsel that the interest payable on the securities is exempt from federal income tax. Additionally, municipal securities include other instruments that directly or indirectly provide economic exposure to income which is derived from municipalities. There may be times when there are not enough municipal securities available to meet the Fund's needs. On these occasions, the Fund may invest in repurchase agreements or U.S. Treasury securities that may be subject to federal income tax. The Fund may invest in debt securities issued by governmental entities, certain issuers identified with the U.S. government and private issuers. The Fund may invest in municipal mortgage-backed and asset-backed securities. The Fund may invest a significant portion or all of its assets in municipal mortgage- backed securities at the adviser's discretion.