Launched by Nuveen Investments Inc., Nuveen Select Tax-Free Income Portfolio is a closed-ended fixed income mutual fund that invests in the fixed income markets of the United States. The fund invests in investment-grade municipal securities, with benchmarking courtesy of the S&P National Municipal Bond Index and Lipper General. Established in 1992, it is managed by Nuveen Fund Advisors LLC and is located in the United States.