The US Securities and Exchange Commission (SEC)-mandated Consolidated Audit Trail (CAT) project has come to share many of those traits: it has attracted a level of interest and diversity of participants that few collective FinTech undertakings ever have, and has already seen unexpected and even dramatic twists and turns. To some, it still has a kind of radical appeal and a sweeping ambition—a rare opening to reshape US equities trade surveillance, regulatory relationships, and data availability