31 CFR § 501.602 - Reports to be furnished on demand.
Every person is required to furnish under oath, in the form of reports or otherwise, from time to time and at any time as may be required by the Director, Office of Foreign Assets Control, complete information relative to any transaction, regardless of whether such transaction is effected pursuant to license or otherwise, subject to the provisions of this chapter or relative to any property in which any foreign country or any national thereof has any interest of any nature whatsoever, direct or indirect. The Director may require that such reports include the production of any books of account, contracts, letters or other papers connected with any such transaction or property, in the custody or control of the persons required to make such reports. Reports with respect to transactions may be required either before or after such transactions are completed. Except as provided in parts 596 and 597, the Director may, through any person or agency, conduct investigations, hold hearings, administer oaths, examine witnesses, receive evidence, take depositions, and require by subpoena the attendance and testimony of witnesses and the production of all books, papers, and documents relating to any matter under investigation, regardless of whether any report has been required or filed in connection therewith.
See subpart F of part 597 for the relationship between this section and part 597.