Nuveen Select Tax-Free Income Portfolio Sees Decline in Short Interest Nuveen Select Tax-Free Income Portfolio experienced a 42.3% drop in short interest in February, with totals falling to 49,200 shares. This decline, alongside an average trading volume of 91,600 shares, brings the short-interest ratio to 0.5 days. The fund continues to attract institutional investors, with 16.17% ownership by hedge funds and institutions.1