Normally, the fund invests at least 80% of its net assets in municipal bonds that pay income that is exempt from regular federal income tax. Its investment portfolio will consist primarily of municipal bonds rated A3/A-/A- or higher by an independent rating agency; however the fund may invest in municipal bonds of any credit quality, including up to 20% of its net assets in low- to medium-quality bonds rated Baa1/BBB+/BBB+ or lower. The fund is non-diversified.