Strategy. Under normal market conditions, the Fund invests at least 80% of its net assets (plus the amount of any borrowing for investment purposes) in municipal bonds, the income of which is exempt from federal income taxation. The Fund may count securities that generate income subject to the alternative minimum tax toward the 80% investment requirement. The Fund invests at least 50% of its assets in debt securities that, at the time of purchase, are rated within or below the BBB major rating category by S&P or Fitch, or the Baa major rating category by Moodys, or are unrated but considered to be of comparable quality by the Adviser. The Funds Adviser uses fundamental and other investment research techniques to determine … Show more… Under normal market conditions, the Fund invests at least 80% of its net assets (plus the amount of any borrowing for investment purposes) in municipal bonds, the income of which is exempt from federal income taxation. The Fund may count securities that generate income subject to the alternative minimum tax toward the 80% investment requirement. The Fund invests at least 50% of its assets in debt securities that, at the time of purchase, are rated within or below the BBB major rating category by S&P or Fitch, or the Baa major rating category by Moodys, or are unrated but considered to be of comparable quality by the Adviser. The Funds Adviser uses fundamental and other investment research techniques to determine what municipal bonds to buy and sell. Fundamental techniques assess a securitys value based on factors such as an issuers financial profile, management, and business prospects, as applicable. The Fund uses an interest rate management technique that includes the purchase and sale of U.S. Treasury futures contracts for the purpose of managing the duration, or interest rate risk, of the Fund. Show less