Strategy. The Portfolio pursues its objective by investing principally in high-yielding municipal securities that may be non-investment grade or investment grade. As a matter of fundamental policy, the Portfolio invests, under normal circumstances, at least 80% of its net assets in municipal securities that pay interest that is exempt from federal income tax. These securities may pay interest that is subject to the federal alternative minimum tax (AMT) for certain taxpayers. The Adviser selects securities for purchase or sale based on its assessment of the securities risk and return characteristics as well as the securities impact on the overall risk and return characteristics of the Portfolio. In making this assessment, the Adviser takes into account various factors including the credit quality … Show more… The Portfolio pursues its objective by investing principally in high-yielding municipal securities that may be non-investment grade or investment grade. As a matter of fundamental policy, the Portfolio invests, under normal circumstances, at least 80% of its net assets in municipal securities that pay interest that is exempt from federal income tax. These securities may pay interest that is subject to the federal alternative minimum tax (AMT) for certain taxpayers. The Adviser selects securities for purchase or sale based on its assessment of the securities risk and return characteristics as well as the securities impact on the overall risk and return characteristics of the Portfolio. In making this assessment, the Adviser takes into account various factors including the credit quality and sensitivity to interest rates of the securities under consideration and of the Portfolios other holdings. The Portfolio may invest without limit in lower-rated securities (junk bonds), which may include securities having the lowest rating, and in unrated securities that, in the Advisers judgment, would be lower-rated securities if rated. The Portfolio may invest in fixed-income securities with any maturity or duration. The Portfolio will seek to increase income for shareholders by investing in longer-maturity bonds. Consistent with its objective of seeking a higher level of income, the Portfolio may experience greater volatility and a higher risk of loss of principal than other municipal funds. The Portfolio may also invest in: forward commitments; tender option bonds (TOBs); zero-coupon municipal securities and variable, floating and inverse floating-rate municipal securities; certain types of mortgage-related securities; and derivatives, such as options, futures contracts, forwards and swaps. The Portfolio may make short sales of securities or maintain a short position, and may use other investment techniques. Show less