31 CFR § 281.5 - Depositaries.
(a) Except as provided in paragraph (b) of this section, foreign exchange which is held by accountable officers for account of the Secretary and foreign exchange acquired by accountable officers by purchase or otherwise, which is not immediately disbursed but is held by such officers for their own account or for the account of any agency, shall be maintained only in depositaries designated by the Secretary. Unless otherwise directed by the Secretary, accountable officers are not required to have separate depositary accounts for foreign exchange held for the Secretary's account.
(b) Accountable officers may carry foreign exchange as cash outside depositaries only pursuant to authority granted in accordance with Treasury Department Circular No. 1030 dated July 24, 1959, as amended.
(c) Deposits in and withdrawals from foreign exchange accounts maintained with depositaries in the name of the United States Treasury will be made only as directed by the Secretary.