His online tutoring firm, GSX Techedu Inc., has been battered in the stock market, tumbling more than 80% since late January. Last month, the investor with the largest exposure to the shares — Bill Hwang’s Archegos Capital Management — imploded when it was unable to answer margin calls. Short sellers including Carson Block’s Muddy Waters and others have been circling since last year, and GSX’s latest financial results showed wider-than-expected losses. It faced a new barrage this month, with Grizzly Research issuing a report questioning the number and qualifications of teachers working for the company, and arguing that auditor Deloitte shouldn’t give an opinion on the firm’s annual report.