The investment seeks after-tax total return. The fund invests at least 80% of its net assets (plus any borrowings for investment purposes) in a diversified portfolio of municipal obligations, the interest on which is exempt from regular federal income tax. It normally invests in municipal obligations rated in the three highest rating categories or, if unrated, determined by the investment adviser to be of comparable quality at the time of purchase. The adviser currently targets an average portfolio duration of approximately 2 - 4.5 years and an average weighted portfolio maturity of approximately 3 - 6 years.