CECO Environmental Corp. (NASDAQ:CECO – Get Free Report) was the recipient of a large increase in short interest in the month of May. As of May 15th, there was short interest totalling 1,290,000 shares, an increase of 15.2% from the April 30th total of 1,120,000 shares. Approximately 4.4% of the company’s stock are sold short. […]