This fund aims to provide a substantial level of current income that is exempt from ordinary federal income taxes, all while diligently working to preserve investors' capital. To fulfill this goal, the fund typically allocates at least 80% of its holdings, or derives a minimum of 80% of its revenue, from securities that are not subject to regular federal income tax. A significant portion of the portfolio, specifically at least 65%, is invested in debt instruments with a credit rating of BBB- or Baa3 or higher from Nationally Recognized Statistical Rating Organizations chosen by the fund's adviser, or in unrated securities judged by the adviser to be of comparable quality.