The Fund seeks a high level of income exempt from federal income tax, with capital appreciation as a secondary objective. It invests at least 80% of net assets in municipal securities paying federally tax-exempt interest and at least 75% in bonds rated BBB+/Baa1 or lower or unrated, with about half expected below investment grade. It may hold defaulted or distressed bonds (intended up to 20%) and AMT-subject private activity bonds, adds leverage through inverse floaters (expected 10% to 25% of net assets), and may use futures and other derivatives.