First Trust NASDAQ Clean Edge Green Energy Index Fund (NASDAQ:QCLN - Get Rating) saw a large drop in short interest during the month of May. As of May 31st, there was short interest totalling 304,700 shares, a drop of 14.3% from the May 15th total of 355,500 shares. Based on an average daily volume of 314,200 shares, the short-interest ratio is presently 1.0 days.