Opendoor Technologies Inc. shares climbed more than 20% in intraday trading on Monday, lifting the online home-buying platform’s market capitalization back above $2.3 billion. The rally extends a week-long surge that has taken the stock from $1.78 to roughly $3.77 as retail investors increased their bets on the company. The jump followed the resignation of Chief Executive Officer Carrie Wheeler. The board named an interim leader while it searches for a permanent replacement, a transition investors see as an opportunity to quicken Opendoor’s push into artificial-intelligence tools for pricing and operations. The leadership change comes weeks after the firm reported a return to positive adjusted EBITDA, helping it stave off an earlier Nasdaq delisting warning. Data provider ORTEX estimates that about 23% of Opendoor’s free float is sold short, with share-borrowing utilization near 94%, an average cost-to-borrow of 8.8%, and roughly 355 million shares on loan. Analysts said the elevated short positioning, coupled with renewed retail enthusiasm, could be intensifying the stock’s gains.