The investment seeks as high a level of current income exempt from federal income tax as is consistent with relative stability of principal. Under normal circumstances, the fund invests at least 80% of its Assets in municipal securities, the income from which is exempt from federal income tax. For purposes of this policy, "Assets" means net assets, plus the amount of borrowings for investment purposes. Up to 100% of the fund's assets may be invested in short-term municipal instruments such as variable rate demand notes, short-term municipal notes and tax-exempt commercial paper.