The investment seeks current income exempt from regular federal income tax. The fund normally invests at least 80% of net assets in municipal obligations that are exempt from such taxes. It primarily invests in municipal obligations that are insured as to principal and interest payments by insurers having a claims-paying ability rated at least investment grade, provided that at least 50% of such assets is invested in obligations insured by insurers having a claims-paying ability rated at least A. The fund normally acquires municipal obligations with maturities of ten years or more. It is nondiversified.