Strategy. The fund invests primarily in bonds and other debt instruments. The fund will normally invest at least 80% of its assets in, or derive at least 80% of its income from, securities that are exempt from regular federal income tax. The fund may substantially invest in securities that may subject you to federal alternative minimum tax. The fund may also invest in debt securities rated BB+ or below and Ba1 or below by Nationally Recognized Statistical Rating Organizations designated by the funds investment adviser, or unrated but determined by the funds investment adviser to be of equivalent quality. Securities rated BB+ or below and Ba1 or below are sometimes referred to as junk bonds. The fund may invest in debt … Show more… The fund invests primarily in bonds and other debt instruments. The fund will normally invest at least 80% of its assets in, or derive at least 80% of its income from, securities that are exempt from regular federal income tax. The fund may substantially invest in securities that may subject you to federal alternative minimum tax. The fund may also invest in debt securities rated BB+ or below and Ba1 or below by Nationally Recognized Statistical Rating Organizations designated by the funds investment adviser, or unrated but determined by the funds investment adviser to be of equivalent quality. Securities rated BB+ or below and Ba1 or below are sometimes referred to as junk bonds. The fund may invest in debt securities of any maturity or duration. The fund is nondiversified, which allows it to invest a greater percentage of its assets in any one issuer than would otherwise be the case. The investment adviser uses a system of multiple portfolio managers in managing the funds assets. Under this approach, the portfolio of the fund is divided into segments managed by individual managers. The fund relies on the professional judgment of its investment adviser to make decisions about the funds portfolio investments. The basic investment philosophy of the investment adviser is to seek to invest in attractively priced securities that, in its opinion, represent good, long-term investment opportunities. Securities may be sold when the investment adviser believes that they no longer represent relatively attractive investment opportunities.For more information regarding the investment process of the fund, see the Management and organization section of this prospectus. Show less