31 C.F.R. § 591.507
(a) Receipts of payment of professional fees and reimbursement of incurred expenses for the provision of legal services authorized pursuant to § 591.506(a) to or on behalf of any person whose property and interests in property are blocked pursuant to § 591.201, are authorized from funds originating outside the United States, provided that the funds received by U.S. persons as payment of professional fees and reimbursement of incurred expenses for the provision of legal services authorized pursuant to § 591.506(a) do not originate from:
(b) Reports.
(1) U.S. persons who receive payments in connection with legal services authorized pursuant to § 591.506(a) must submit annual reports no later than 30 days following the end of the calendar year during which the payments were received providing information on the funds received. Such reports shall specify:
(ii) If applicable:
Note to paragraph (a) of § 591.507: This paragraph authorizes the blocked person on whose behalf the legal services authorized pursuant to § 591.506(a) are to be provided to make payments for authorized legal services using funds originating outside the United States that were not previously blocked. Nothing in this paragraph authorizes payments for legal services using funds in which any other person whose property and interests in property are blocked pursuant to § 591.201, any other part of this chapter, or any Executive order has an interest.
Note to § 591.507: U.S. persons who receive payments in connection with legal services authorized pursuant to § 591.506(a) do not need to obtain specific authorization to contract for related services that are ordinarily incident to the provision of those legal services, such as those provided by private investigators or expert witnesses, or to pay for such services. Additionally, U.S. persons do not need to obtain specific authorization to provide related services that are ordinarily incident to the provision of legal services authorized pursuant to § 591.506(a).
[80 FR 39677, July 10, 2015, as amended at 84 FR 64417, Nov. 22, 2019]