OFAC SDN List
The Specially Designated Nationals and Blocked Persons List maintained by OFAC. This is the primary U.S. sanctions list, and any individual or entity on it is blocked from transacting with U.S. persons.
An SDN listing is a blocking sanction: assets are frozen and all dealings by U.S. persons are prohibited outright. That is a materially different consequence from OFAC’s separate Consolidated (non-SDN) List, which aggregates narrower programmes — sectoral sanctions on certain debt and equity, the Non-SDN Chinese Military-Industrial Complex list, foreign-sanctions-evader designations — each carrying its own specific restriction rather than a full freeze. Treating every OFAC hit as an SDN-style block over-blocks legitimate business; treating a real SDN hit as a lesser restriction misses a full prohibition.
Liability under OFAC is strict: a business that deals with a designated party can be penalised whether or not it knew, or should have known, that the party was on the list. The list itself changes without notice — a customer clear at onboarding can be designated the following week — which is the core argument for ongoing monitoring rather than a one-time onboarding check. It is also only one of several lists a given business needs: EU, UN, UK, and Australian DFAT sanctions lists bind different people under different law and none is a superset of another.