Strategy. Under normal circumstances, the fund invests at least 80% of its assets in municipal securities and in participation or other interests in municipal securities issued by banks, insurance companies or other financial institutions. Municipal securities are securities and other investments with similar economic characteristics the interest on which is exempt from regular federal income tax. The funds 80% policy may not be changed without a shareholder vote. Interest on municipal securities may be subject to the federal alternative minimum tax. Municipal securities include debt obligations issued by any of the 50 states and certain other municipal issuers and their political subdivisions, agencies and public authorities, certain other governmental issuers (such as Puerto Rico, the U.S. Virgin Islands and Guam) and … Show more… Under normal circumstances, the fund invests at least 80% of its assets in municipal securities and in participation or other interests in municipal securities issued by banks, insurance companies or other financial institutions. Municipal securities are securities and other investments with similar economic characteristics the interest on which is exempt from regular federal income tax. The funds 80% policy may not be changed without a shareholder vote. Interest on municipal securities may be subject to the federal alternative minimum tax. Municipal securities include debt obligations issued by any of the 50 states and certain other municipal issuers and their political subdivisions, agencies and public authorities, certain other governmental issuers (such as Puerto Rico, the U.S. Virgin Islands and Guam) and other qualifying issuers. These securities include participation or other interests in municipal securities issued or backed by banks, insurance companies and other financial institutions. Some municipal securities, such as general obligation issues, are backed by the issuers taxing authority, while other municipal securities, such as revenue issues, are backed only by revenues from certain facilities or other sources and not by the issuer itself. Although the fund seeks to minimize risk by investing in municipal securities from a number of different states and localities, the fund may, from time to time, invest over 25% of its assets in municipal securities from one state or region. The fund attempts to minimize the volatility in its net asset value per share, although there can be no assurance that this will be the case. The fund focuses on investment grade bonds (that is, securities rated in the Baa/BBB categories or above or, if unrated or deemed to be unrated by the subadviser, determined to be of comparable credit quality by the subadviser), but may invest up to 20% of its assets in below investment grade bonds (commonly known as high yield or junk bonds). Although the fund may invest in securities of any maturity, the fund normally expects to maintain a dollar-weighted average effective duration, as estimated by the subadviser, of three years or less. Effective duration seeks to measure the expected sensitivity of market price to changes in interest rates, taking into account the anticipated effects of structural complexities (for example, some bonds can be prepaid by the issuer). The fund may also invest in securities of other open-end or closed-end investment companies, including exchange-traded funds (ETFs), that invest primarily in municipal securities. Instead of, and/or in addition to, investing directly in particular securities, the fund may use instruments such as derivatives, including options, futures contracts and inverse floating rate instruments issued in tender option bond transactions and other synthetic instruments that are intended to provide economic exposure to the securities or the issuer or to be used as a hedging technique. The fund may use one or more types of these instruments without limit, subject to applicable regulatory requirements. These instruments are taken into account when determining compliance with the funds 80% policy. For additional information regarding derivatives, see More on the funds investment strategies, investments and risksDerivatives in the Prospectus. The fund may also engage in a variety of transactions using derivatives in order to change the investment characteristics of its portfolio (such as shortening or lengthening duration) and for other purposes. The fund may leverage its assets by investing proceeds received through tender option bond transactions, which is considered a form of borrowing. See More on the funds investment strategies, investments and risksTender option bonds in the Prospectus. Show less