The investment seeks the maximum amount of current income exempt from federal income tax as is consistent with the preservation of capital. The fund invests at least 80% of its assets in municipal bonds rated, at the time of purchase, A or higher or the unrated equivalent as determined by the adviser. The fund may invest up to 20% of its assets in municipal bonds rated below A, including bonds rated below investment grade ("high yield" or "junk" bonds) or the unrated equivalent as determined by the adviser. The dollar-weighted average maturity of the fund's portfolio generally is between three and ten years.