U.S. Senator Elizabeth Warren (D-MA) urged Michael Hsu, acting head of the Office of the Comptroller of the Currency (OCC), on Friday to address Citibank’s longstanding operational failures.

In a letter to Hsu, Warren warned that Citibank “has become ‘too-big-to-manage’ and committed a number of massive blunders in recent years,” adding that despite multiple regulatory actions, the bank continues to falter. She criticized the OCC’s lack of decisive action and indicated that breaking up the bank may now be necessary under Hsu’s own regulatory framework. The senator wrote:

Citi, the fourth largest bank in the United States, has failed to reform and modernize its operations despite being the subject of multiple enforcement actions by the OCC and the Federal Reserve.

She explained that the bank has struggled with several regulatory and operational crises, including failing two Federal Reserve stress tests and mishandling its “living will,” a document required for bankruptcy management. Warren highlighted other notable failures, such as repeated violations of a Federal Reserve rule aimed at protecting customer deposits. Despite these repeated issues, regulators have imposed penalties, but Citi continues to fall short of expectations.

Warren emphasized the lack of meaningful progress over the years. She pointed to Hsu’s escalation framework, which includes warnings, enforcement actions, and breaking up banks that repeatedly fail. The lawmaker wrote:

The evidence is clear: Citi has failed to make sufficient progress, despite being provided four years to do so. Following your own escalation framework, it may be time to break up Citi.