Nuveen Select Maturities Municipal Fund is a diversified closed-end management investment company. The Fund's primary investment objective is current income exempt from regular federal income tax, consistent with the preservation of capital. Its secondary investment objective is the enhancement of portfolio value relative to the municipal bond market through investments in tax-exempt municipal obligations. The Fund invests at least 80% of its assets in municipal securities and other related investments, the income from which is exempt from regular federal income taxes. The Fund invests at least 80% of its assets in municipal securities with effective remaining maturities of about 15 years or less at the time of purchase. The Fund may invest up to 20% of its managed assets in municipal securities that at the time of investment are rated below investment grade or are unrated. The Fund's investment adviser is Nuveen Fund Advisors, LLC. Nuveen Asset Management, LLC is its sub adviser.