Gensler Is Poised to Confront Stock Market Hit by Historic Mania

From the mania engulfing GameStop Corp. and penny stocks to the explosive growth of SPACs, a nervous question is starting to make the rounds within American finance: Will the next sheriff of Wall Street be able to tame these wild markets?

Gary Gensler, President Joe Biden’s pick to lead the Securities and Exchange Commission, is poised to confront a run-up in share prices with few parallels in modern history. Perhaps more worrisome, the astronomical valuations are tied to companies like GameStop that aren’t expected to turn a profit for years, or, in the case of special-purpose acquisition companies, stocks ...