SDN

The Specially Designated Nationals and Blocked Persons List (SDN) is maintained by the US Treasury Department's Office of Foreign Assets Control (OFAC). Placement on the SDN list means all assets within US jurisdiction are frozen, and US persons are prohibited from transacting with the designated entity or individual. Non-US entities face secondary sanctions risk: doing business with SDN-listed parties can result in their own designation, loss of US dollar correspondent banking access, or exclusion from US-regulated markets. OFAC issues SDN designations through Executive Orders (primarily 13902 and 13224 in the Iran context) and publishes rounds with accompanying press bulletins. In this conflict, OFAC has conducted at least ten SDN rounds since the war began, targeting shadow-fleet tankers, IRGC procurement networks, Iranian foreign-exchange houses, and satellite firms.

A structural feature of the Iran SDN campaign has been the exclusion of mainland Chinese refineries despite their documented role in purchasing IRGC oil. MOFCOM Announcement No. 21 (2 May 2026) directed Chinese nationals to disregard OFAC designations made under EO 13902 and EO 13846, and the five named mainland refineries — Hengli Petrochemical, Shandong Shouguang Luqing, and three others — were excluded from every OFAC round following 11 May. OFAC instead targeted only Hong Kong-registered shells and flag-of-convenience tankers, creating a legal gap China's blocking rules explicitly exploit.

The SDN list is one of the most powerful non-military tools in US Foreign Policy. Designation triggers automatic asset freeze, cuts off US dollar clearing, and can isolate designated parties from the global financial system. In wartime, SDN rounds function as a parallel economic front: each round adds pressure on Iran's oil revenue, shipping logistics, and procurement networks, though the mainland-refinery exclusion gap and MOFCOM's blocking rules have materially constrained its effectiveness in this conflict.