Reuters sources said that Mulvaney has neither ordered subpoenas against Equifax nor collected any sworn testimony from company executives. Additionally, reviews of how Equifax protects its data and on-site cybersecurity exams of other credit bureaus -- which the Federal Reserve, Federal Deposit Insurance Corp and Office of the Comptroller of the Currency all offered to assist with -- have been put on hold. The bank regulators who had offered to help were reportedly told that there were no exams planned and their assistance wouldn't be needed.

In their letter, the senators expressed their concern over these reports and reiterated the duty the CFPB has to not only investigate the breach but to bring action against Equifax if deemed necessary. "Consumer reporting agencies and the data they collect play a central role in consumers' access to credit and the fair and competitive pricing of that credit," they wrote. "Therefore, the CFPB has a duty to supervise consumer reporting agencies, investigate how this breach has or will harm consumers and bring enforcement actions as necessary." They specifically ask Mulvaney and Deputy Director Leandra English whether the probe has been halted and if so, why and under whose direction. They also ask about any plans for on-site exams of Equifax and other bureaus, what steps they've taken in the investigation so far and whether they're coordinating with the FTC and its Equifax probe.

The senators have requested a response by February 19th.