State banking regulators are taking the Office of the Comptroller of the Currency to court over its proposal to establish a special-purpose national bank charter for financial technology companies.

In the lawsuit filed Wednesday in federal district court in Washington, D.C., the Conference of State Bank Supervisors, which represents state-chartered banks nationally, claims that the OCC's charter proposal violates the National Bank Act and other federal banking laws.

In the lawsuit, which appears to be the first filed against the OCC over the proposal, the state banking regulators accuse the OCC of overstepping its authority under the National Bank Act. The state regulators claim the comptroller's office, led by Thomas Curry, lacks authority to create a special-purpose charter without approval from Congress.