“There’s trading venues and lending venues where they coalesce around these, and they have not just dozens but hundreds and sometimes thousands of tokens on them,” Gensler said Monday at the Code Conference in Beverly Hills, California. “This is not going to end well if it stays outside the regulatory space.”

The regulator has previously labeled crypto as the “Wild West” and signaled that he wants more robust oversight of the markets. Last week, Republican Senator Pat Toomey called on Gensler to codify rules for the industry, rather than pursuing “regulation by enforcement.”

At Monday’s conference, Gensler declined to comment on remarks made earlier this month by Coinbase Global Inc. Chief Executive Officer Brian Armstrong that the SEC was regulating by litigation and engaging in “sketchy behavior.”