A notorious short-seller unloaded on SoFi. The stock shrugged it off

Muddy Waters made its name as a short-selling firm that exposed accounting trickery at publicly-traded Chinese firms. On March 17, the firm took aim at a new target: It accused SoFi, known for home and student loans, of a host of book-keeping shenanigans designed to enrich top executives at the expense of shareholders. These are the sort of accusations that, if true, could tank a company’s stock. But so far the market doesn’t appear to be buying Muddy Waters’ latest tale.

The short-seller set out its allegations on March 17...