In a letter to the Comptroller of the Currency, Warren argued nine national trust bank charter approvals for crypto firms violated the National Bank Act.

The Senate Banking Committee's top Democrat sent a letter to the Office of the Comptroller of the Currency questioning the charters of nine crypto firms.

Last year, the OCC granted conditional approvals to Circle, Ripple, BitGo, Fidelity, and Paxos, as well as other firms more recently.