The investment seeks to provide investors with as high a level of income exempt from federal income taxes as is consistent with prudent investment management and the preservation of shareholders’ capital. The fund invests at least 80% of its total assets in investment grade municipal securities whose interest is free from federal income taxes, including the federal alternative minimum tax. Although the fund tries to invest all of its assets in tax-free securities, it is possible that up to 20% of the fund's total assets may be in securities that pay interest that may be subject to the federal alternative minimum tax and in securities that pay taxable interest.