The investment seeks to provide investors with a high level of current income that is exempt from federal income tax; capital appreciation is also an objective, but is secondary to income. The fund invests at least 80% of its net assets, plus the amount of any borrowings for investment purposes, in U.S. dollar-denominated fixed income securities that are exempt from federal income tax. It may invest up to 35% of its total assets in unrated securities, and may invest up to 50% of its total assets in unrated securities and high yield securities.