Strategy. Under normal market conditions, the Fund invests at least 80% of its net assets in municipal securities whose interest is free from federal income taxes, including the federal alternative minimum tax. Although the Fund tries to invest all of its assets in tax-free securities, it is possible that up to 20% of the Funds net assets may be in securities that pay interest that may be subject to the federal alternative minimum tax and in securities that pay interest subject to other federal or state income taxes. The Fund may invest in debt and fixed income securities of any maturity. Under normal market conditions, the Fund seeks to maintain an average effective duration of two to eight years. Effective duration … Show more… Under normal market conditions, the Fund invests at least 80% of its net assets in municipal securities whose interest is free from federal income taxes, including the federal alternative minimum tax. Although the Fund tries to invest all of its assets in tax-free securities, it is possible that up to 20% of the Funds net assets may be in securities that pay interest that may be subject to the federal alternative minimum tax and in securities that pay interest subject to other federal or state income taxes. The Fund may invest in debt and fixed income securities of any maturity. Under normal market conditions, the Fund seeks to maintain an average effective duration of two to eight years. 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 invest in municipal securities that are issued on a when-issued or delayed delivery basis. The Fund may invest in municipal securities rated in any rating category by U.S. nationally recognized rating services (or unrated or short-term rated securities of comparable quality), including below investment grade (also known as "junk bonds") and defaulted securities. The Fund also may invest in insured municipal securities, municipal lease obligations, variable and floating rate securities (primarily variable rate demand notes), zero coupon securities and deferred interest securities. Although the investment manager will search for investments across a large number of municipal securities that finance different types of projects, from time to time, based on economic conditions, the Fund may have significant positions in municipal securities that finance similar types of projects. The Fund may invest in municipal securities that are covered by insurance policies that guarantee the timely payment of principal and interest. The investment manager selects securities that it believes will provide the best balance between risk and return within the Fund's range of allowable investments and typically invests with a long-term time horizon. This means it generally holds securities in the Fund's portfolio for income purposes, although the investment manager may sell a security at any time if it believes it could help the Fund meet its goal. With a focus on income, individual securities are considered for purchase or sale based on various factors and considerations, including credit profile, risk, structure, pricing, portfolio impact, duration management, restructuring, opportunistic trading and tax loss harvesting opportunities. Show less