The investment seeks a high level of current interest income exempt from regular federal, state and, in some cases, local income taxes as is consistent with preservation of capital. The fund invests substantially all of its assets in municipal bonds, primarily in investment grade municipal bonds rated BBB-/Baa3 or higher at the time of purchase. It may invest up to 20% of its net assets in below investment grade municipal bonds, commonly referred to as ?high yield? ?high risk? or ?junk? bonds.