31 CFR § 515.201 - Transactions involving designated foreign countries or their nationals; effective date.
(a) All of the following transactions are prohibited, except as specifically authorized by the Secretary of the Treasury (or any person, agency, or instrumentality designated by him) by means of regulations, rulings, instructions, licenses, or otherwise, if either such transactions are by, or on behalf of, or pursuant to the direction of a foreign country designated under this part, or any national thereof, or such transactions involve property in which a foreign country designated under this part, or any national thereof, has at any time on or since the effective date of this section had any interest of any nature whatsoever, direct or indirect:
(1) All transfers of credit and all payments between, by, through, or to any banking institution or banking institutions wheresoever located, with respect to any property subject to the jurisdiction of the United States or by any person (including a banking institution) subject to the jurisdiction of the United States;
(2) All transactions in foreign exchange by any person within the United States; and
(3) The exportation or withdrawal from the United States of gold or silver coin or bullion, currency or securities, or the earmarking of any such property, by any person within the United States.
(b) All of the following transactions are prohibited, except as specifically authorized by the Secretary of the Treasury (or any person, agency, or instrumentality designated by him) by means of regulations, rulings, instructions, licenses, or otherwise, if such transactions involve property in which any foreign country designated under this part, or any national thereof, has at any time on or since the effective date of this section had any interest of any nature whatsoever, direct or indirect:
(1) All dealings in, including, without limitation, transfers, withdrawals, or exportations of, any property or evidences of indebtedness or evidences of ownership of property by any person subject to the jurisdiction of the United States; and
(2) All transfers outside the United States with regard to any property or property interest subject to the jurisdiction of the United States.
(c) Any transaction for the purpose or which has the effect of evading or avoiding any of the prohibitions set forth in paragraph (a) or (b) of this section is hereby prohibited.
(d) For the purposes of this part, the term foreign country designated under this part and the term designated foreign country mean Cuba and the term effective date and the term effective date of this section mean with respect to Cuba, or any national thereof, 12:01 a.m., e.s.t., July 8, 1963.
(e) When a transaction results in the blocking of funds at a banking institution pursuant to this section and a party to the transaction believes the funds have been blocked due to mistaken identity, that party may seek to have such funds unblocked pursuant to the administrative procedures set forth in § 501.806 of this chapter.