Invests primarily in investment grade U.S. municipal bond obligations. It seeks to provide a high level of current income exempt from federal income tax, consistent with preservation of capital. Up to 15% of its net assets may be invested in inverse floating rate obligations. Announced in the 2007 semi annual report, The Board of Trustees of the Trust approved a non-fundamental investment policy for the Trust allowing it to invest up to 20 percent of its assets in unrated securities that have been determined by the Adviser to be of comparable quality to those rated investment grade.