Shares of Robinhood Markets tumbled on 30 August after the head of the Securities and Exchange Commission signalled that he was open to banning payment for order flow, a practice that accounts for most of the online brokerage’s revenues.

Robinhood shares closed 6.9% lower after Barron’s published an interview with SEC Chairman Gary Gensler in which he said a full prohibition of payment for order flow was “on the table” as part of a broader agency review.