Gruenberg, who has served on the FDIC board for a record 17 years after working for Democrats on the Senate Banking Committee, has been a reliable proponent of tougher financial rules, though his position on cryptocurrencies hasn’t been fully fleshed out. In an October speech on crypto issues, he said stablecoins could have such a profound effect on the banking system that U.S. regulators need to make sure the digital tokens fit in without disruption.