NUMI targets US municipal bonds whose distributions are exempt from regular federal income tax, not including the federal AMT. The portfolio includes obligations issued by US states and their subdivisions, authorities, instrumentalities, and corporations, as well as obligations issued by US territories. The fund invests at least 65% of its net assets in investment grade municipal bonds rated BBB/Baa or higher and up to 35% in high-yield bonds. Under normal market conditions, the fund generally maintains a weighted average maturity of greater than 10 years. The portfolio may include various types of municipal bonds, including general obligation bonds, revenue bonds, participation interests in municipal leases, and zero coupon bonds. The fund may invest without limit in municipal bonds subject to AMT. The sub-adviser uses a value-oriented strategy to identify higher-yielding and undervalued municipal bonds that offer above-average total returns.