Investors upped their short bets on a handful of clean energy and biotechnology stocks during the first half of July, according to FactSet data. Short interest in BioXcel Therapeutics jumped 69% to 8.7 million shares from 5.1 million in the first half of the month, reaching about 43% of the company’s free float of shares, or the amount of stock available for trading. As of Friday, BioXcel is down nearly 54% year to date. Allogene Therapeutics held the greatest short interest of the group, at about 54% of float, with Novavax and ProKidney Corp. also appearing on the list. Short interest declined slightly in ProKidney shares. NVAX YTD mountain Novavax shares year to date Alternative power companies Sunnova , SunPower and Maxeon Solar also made the cut, with short interest increasing about 15%, 49% and 6%, respectively, during the period. The latest data comes as the number of stocks with more than 20% of their outstanding shares sold short has hit the upper end of its historic range, exceeding levels seen during the meme stock craze in early 2021, according to Trivariate Research . Given this setup, CNBC Pro used FactSet data to screen for companies most susceptible to a short squeeze. This phenomenon occurs when a shorted stock climbs higher, forcing investors who are betting against the stock to buy back shares to temper their losses. This so-called short covering results in shares moving even higher. The list below includes companies listed on the New York Stock Exchange and Nasdaq with short interest accounting for more than 25% of float, and a market cap of at least $100 million as of July 14. Here are the names included in the list: Short interest declined about 4% for shares of Carvana , but hovers at around 47% of float for the online used-car seller. Shares have been volatile in recent months and have surged nearly 800% since the start of the year. C3.ai was also included. Short interest in shares declined 8.6% during the first half of July, although about 35% of its shares are sold short. The artificial intelligence stock has surged about 250% this year as investors bet on the prospects of the buzzy technology trend. For the month, shares have added nearly 8%. Retail stock Groupon and clothing manufacturer Guess? saw short interest leap 10% since the end of June.