31 C.F.R. § 595.406 Provision of services.
Title 31 - Money and Finance: Treasury
(a) Except as provided in §595.206, the prohibitions contained in §§595.201 and 595.204 apply to services performed by U.S. persons, wherever located: (1) On behalf of, or for the benefit of, a specially designated terrorist; or (2) With respect to property interests of a specially designated terrorist. (b) Example: U.S. persons may not, except as authorized by the Office of Foreign Assets Control by or pursuant to this part, provide legal, accounting, public relations, educational, or other services to a specially designated terrorist. See §595.506.
Title 31: Money and Finance: Treasury
PART 595—TERRORISM SANCTIONS REGULATIONS
Subpart D—Interpretations
§ 595.406 Provision of services.

