The U.S. Securities and Exchange Commission is probing registered investment advisers over whether they are meeting rules around custody of client crypto assets, three sources with knowledge of the inquiry told Reuters.

The SEC has been questioning advisers' efforts to follow the agency's rules around custody of clients' digital assets for several months, but the probe has gathered pace in the wake of the blow-up of crypto exchange FTX, the sources said. They spoke on condition of anonymity as the inquiries are not public.