The investment seeks to provide a high level of current income exempt from federal income tax, consistent with the preservation of capital. Under normal circumstances, the fund invests at least 80% of its net assets (plus any borrowings for investment purposes) in municipal securities, the income from which is exempt from federal income tax. Its average portfolio duration, as calculated by the Adviser, is typically maintained at +/- 3 years of the average benchmark duration, which is the average duration of all the constituent bonds in the Bloomberg Barclays Municipal Bond Index, which as of December 31, 2020 was 4.53 years.