Strategy. Under normal market conditions, the Fund invests at least 80% of the sum of its net assets and the amount of any borrowings for investment purposes in municipal bonds that pay interest that is exempt from regular federal personal income tax. Regular federal personal income tax is different from, and does not include, the federal alternative minimum tax. These municipal bonds include obligations issued by U.S. states and their subdivisions, authorities, instrumentalities and corporations, as well as obligations issued by U.S. territories (such as Puerto Rico, the U.S. Virgin Islands and Guam) that pay interest that is exempt from regular federal personal income tax. The Fund may invest without limit in securities that generate income subject to the alternative minimum … Show more… Under normal market conditions, the Fund invests at least 80% of the sum of its net assets and the amount of any borrowings for investment purposes in municipal bonds that pay interest that is exempt from regular federal personal income tax. Regular federal personal income tax is different from, and does not include, the federal alternative minimum tax. These municipal bonds include obligations issued by U.S. states and their subdivisions, authorities, instrumentalities and corporations, as well as obligations issued by U.S. territories (such as Puerto Rico, the U.S. Virgin Islands and Guam) that pay interest that is exempt from regular federal personal income tax. The Fund may invest without limit in securities that generate income subject to the alternative minimum tax on individuals. The Fund is a long-term bond fund and, as such, will generally maintain, under normal market conditions, an investment portfolio with an overall weighted average maturity of greater than 10 years. The Fund invests significantly in lower-quality long-term municipal bonds and may invest up to 15% of its net assets in municipal securities whose interest payments vary inversely with changes in short-term tax-exempt interest rates ( inverse floaters ). Inverse floaters are derivative securities that provide leveraged exposure to underlying municipal bonds. The Funds investments in inverse floaters are designed to increase the Funds income and returns through this leveraged exposure. These investments are speculative, however, and also create the possibility that income and returns will be diminished. These investment strategies should be considered high risk relative to strategies employed by investment grade municipal bond funds. The Fund may invest in inverse floaters that create effective leverage of up to 30% of the Funds total investment exposure. Under normal market conditions, the Fund invests at least 65% of its net assets in low- to medium-quality bonds rated BBB/Baa or lower at the time of purchase by at least one independent rating agency or, if unrated, judged by the Funds sub-adviser to be of comparable quality. Below investment grade municipal bonds (those rated BB/Ba or lower) are commonly referred to as high yield or junk bonds. The Fund may invest up to 10% of its net assets in defaulted municipal bonds (i.e., bonds on which the issuer has not paid principal or interest on time). The Fund may invest in all types of municipal bonds, including general obligation bonds, revenue bonds and participation interests in municipal leases. The Fund may invest in zero coupon bonds, which are issued at substantial discounts from their value at maturity and pay no cash income to their holders until they mature. The Fund may utilize the following derivatives: futures contracts; options on futures contracts; swap agreements, including interest rate swaps, total return swaps and credit default swaps, and options on swap agreements. The Fund may use these derivatives in an attempt to manage market risk, credit risk and yield curve risk, and to manage the effective maturity or duration of securities in the Funds portfolio. The Funds sub-adviser uses a research-intensive investment process to identify high-yielding municipal bonds that offer attractive value in terms of their current yields, prices, credit quality, liquidity and future prospects. The sub-adviser may choose to sell municipal bonds with deteriorating credit or limited upside potential compared to other available bonds. Show less