Redemptions can erode returns for early SPAC shareholders who stick around. They end up bearing a greater share of the SPAC’s expenses, said Michael Klausner, a professor of business and law at Stanford University who’s written about the hidden cost of blank-check companies. Those include the fees paid to banks, as well as “the promote,” the loads of free stock that go to the sponsors.

“The SPACs are a pile of money that the banks can’t resist,” Klausner said. The variety of fees “is a really good deal for the banks,” he said. “Which means a really bad deal for the shareholders.”