31 CFR §549.406

The prohibitions in § 549.201 on transactions or dealings involving blocked property apply to transactions by any U.S. person in a location outside the United States with respect to property held in the name of a person whose property and interests in property are blocked pursuant to § 549.201(a), or property in which a person whose property and interests in property are blocked pursuant to § 549.201(a) has or has had an interest since the effective date.