The OCC is the primary regulator of banks chartered under the National Bank Act (12 USC 1 et seq.) and federal savings associations chartered under the Home Owners' Loan Act of 1933 (12 USC 1461 et seq.). The OCC's regulations, derived from these acts, are in title 12 of the Code of Federal Regulations, "Banks and Banking" (12 CFR 1–199).

The OCC may take enforcement actions for violations of laws, rules or regulations, final orders or conditions imposed in writing; unsafe or unsound practices; and breach of fiduciary duty by institution-affiliated parties.