The frenzy has already led to trouble. The stock of Nikola, an electric car start-up that went public via a SPAC in June, has plunged more than 80 percent after Hindenburg Research, an investment fund, accused the company in September of lying about its technology, overstating business deals and deceptively rolling a truck down a hill in a product video. Trevor Milton, Nikola’s founder and chairman, resigned, and the Securities and Exchange Commission and Justice Department have started investigating the company.The S.E.C. has also opened inquiries into Clover Health, a health insurance start-up, and Lordstown Motors, an …
