In a speech to the LendIT conference in New York, Curry offered a stout defence to charges laid by banking trade bodies and state regulators over its plans.

"To be clear, the National Bank Act does give the OCC the legal authority to grant national bank charters to companies engaged in the business of banking," Curry told the conference. "That authority includes granting charters to companies that limit their business models to certain aspects of banking, and it is not circumscribed just because a company delivers banking services in new ways with innovative technology."

Curry says the agency received over 100 comments over its proposals, none more stinging than a letter from Maria Vullo of the New York State Department of Financial Services, warning that the OCC "should not use technological advances as an excuse to attempt to usurp state laws that already regulate fintech activities". The proposals, wrote Vullo would "imperil crucially important state-based consumer protection laws and increase the risks presented by nonbank entities".

"That's wrong," Curry fires back, pointing out that consumer protection has changed significantly since the financial crisis. "State laws that address anti-discrimination, fair lending, debt collection, taxation, zoning, crime, and torts, generally apply to national banks and will also apply to fintech companies that become national banks."

Nor is the OCC "somehow mixing banking and commerce", says Curry. "The OCC understands the importance of maintaining the longstanding separation of banking and commerce," he says. "Comingling banking and commerce could introduce risks associated with non-banking-related commercial activities, interfere with the allocation of credit, and foster anti-competitive effects and undesirable concentrations of economic power."

Curry says the OCC is working to publish a supplement to its existing Licensing Manual that will further clarify its approach to evaluating applications from fintech companies.