12 U.S.C. § 3402

Except as provided by section 3403(c) or (d), 3413, or 3414 of this title, no Government authority may have access to or obtain copies of, or the information contained in the financial records of any customer from a financial institution unless the financial records are reasonably described and— (1) such customer has authorized such disclosure in accordance with section 3404 of this title ; (2) such financial records are disclosed in response to an administrative subpena or summons which meets the requirements of section 3405 of this title ; (3) such financial records are disclosed in response to a search warrant which meets the requirements of section 3406 of this title ; (4) such financial records are disclosed in response to a judicial subpena which meets the requirements of section 3407 of this title ; or (5) such financial records are disclosed in response to a formal written request which meets the requirements of section 3408 of this title .