Strategy. Under normal market circumstances, the Fund invests at least 80% of its net assets (plus any borrowings for investment purposes) in municipal obligations, the interest on which is exempt from regular federal income tax (the 80% Policy). Municipal obligations are debt obligations issued by or on behalf of state, territories and possessions of the United States, and the District of Columbia and their political subdivisions, agencies or instrumentalities. The Fund may invest without limit in obligations the income from which is subject to the federal alternative minimum tax. The Fund has a flexible investment strategy and may invest in obligations of any duration and credit quality. The Fund also may invest up to 50% of its net assets in obligations … Show more… Under normal market circumstances, the Fund invests at least 80% of its net assets (plus any borrowings for investment purposes) in municipal obligations, the interest on which is exempt from regular federal income tax (the 80% Policy). Municipal obligations are debt obligations issued by or on behalf of state, territories and possessions of the United States, and the District of Columbia and their political subdivisions, agencies or instrumentalities. The Fund may invest without limit in obligations the income from which is subject to the federal alternative minimum tax. The Fund has a flexible investment strategy and may invest in obligations of any duration and credit quality. The Fund also may invest up to 50% of its net assets in obligations rated below investment grade and in unrated obligations considered to be of comparable quality by the investment adviser (junk bonds). Below investment grade obligations are those obligations rated below Baa by Moodys Investors Service, Inc. (Moodys), or below BBB by either S&P Global Ratings (S&P) or Fitch Ratings (Fitch). For the purposes of rating restrictions, if securities are rated differently by two or more rating agencies, the highest rating is used. The Fund may invest up to 20% of its net assets in other debt obligations, including (but not limited to) taxable municipal obligations, U.S. Treasury securities and obligations of the U.S. Government, its agencies and instrumentalities (Agency Securities). The Fund may purchase derivative instruments, which derive their value from another instrument, security or index. The Fund may purchase or sell various kinds of residual interest bonds, financial futures contracts and options thereon to hedge against changes in interest rates or as a substitute for the purchase of portfolio securities. The Fund also may enter into interest rate swaps, forward rate contracts and credit derivatives, which may include credit default swaps, total return swaps or credit options, as well as purchase an instrument that has greater or lesser credit risk than the municipal bonds underlying the instrument. Except as required by applicable regulation, there is no stated limit on the Funds use of derivatives. In pursuing its investment objective, the Fund may acquire municipal obligations with varying maturities. Depending on the Funds average maturity, the interest rate risk described below may be more or less significant for the Fund. The longer the Funds average maturity, the more significant interest rate risk will be for the Fund. The Fund may invest 25% or more of its total assets in certain types of municipal obligations (such as general obligations, municipal leases, principal only municipal investments, revenue bonds and industrial development bonds) and in one or more sectors (such as housing, hospitals, healthcare facilities or utilities). The Fund may invest in pooled investment vehicles, including exchange-traded funds (ETFs), in order to seek exposure to the municipal markets or municipal market sectors. The Fund may invest in restricted securities. The investment advisers process for selecting obligations for purchase and sale emphasizes the creditworthiness of the issuer or other person obligated to repay the obligation and the relative value of the obligation in the market. In evaluating creditworthiness, the investment adviser considers ratings assigned by rating agencies and generally performs additional credit and investment analysis. When deemed by the investment adviser to be relevant to its evaluation of creditworthiness and when applicable information is available, the investment adviser considers environmental, social and/or governance issues (referred to as ESG) which may impact the prospects of an issuer (or obligor) or financial performance of an obligation. When considered, one or more ESG issues are taken into account alongside other factors in the investment decision-making process and are not the sole determinant of whether an investment can be made or will remain in the Funds portfolio. The portfolio managers generally will seek to enhance after-tax total return by balancing investment considerations and tax considerations. The Fund expects to actively engage in relative value trading to take advantage of price appreciation opportunities or to realize capital losses. A portion of the Funds distributions generally will be subject to the federal alternative minimum tax. The Fund may not be suitable for investors subject to the federal alternative minimum tax. Show less