Iran Oil Sanctions Squeeze: Who Is Exposed to Secondary Sanctions

China purchases approximately 90 percent of Iran's oil exports, with teapot refineries accounting for the majority of these imports, according to a Treasury alert of 28 April 2026. That concentration is why Washington's latest sanctions wave matters beyond Tehran: the counterparties on the other side of each cargo are increasingly exposed.

This article maps who is exposed, where enforcement has already landed, and where the gaps in the public record remain as of 1 November 2026.

From 'maximum pressure' to 'Operation Economic Outcast'

On 24 August 2026, OFAC sanctioned nearly 60 entities, individuals and vessels, and Treasury announced a campaign expanding secondary sanctions risk to any country or company doing business with Tehran across five key sectors. The campaign was named "Operation Economic Outcast" and announced by Bessent as part of a wider effort to target Iran's oil sales, financial channels and sanctions-evasion networks.

Two features make the campaign hard to price. First, Washington had not yet named which countries would face secondary sanctions. Second, the announcement named no specific countries beyond Iran and established no timelines. The research found no current, official list of secondary-sanctions countries. For compliance teams, that ambiguity is itself the risk.

Shippers: the shadow fleet in the crosshairs

The most mature enforcement track targets vessels. On 8 October 2026, OFAC designated 17 vessels and 13 companies under Executive Order 13902 for carrying Iranian crude, fuel oil, LPG, naphtha, methanol, bitumen and petrochemicals. Treasury said the action effectively neutralizes the vast majority of Iran's remaining shadow fleet. The 13 designated firms are mainly in the Marshall Islands, Hong Kong and China.

A concrete example: according to Treasury, the Panama-flagged chemical/oil products tanker MACKEREL transported over 500,000 barrels of Iranian high sulfur fuel oil since December 2025. The State Department had separately identified 14 shadow-fleet vessels as blocked property of entities involved in transporting Iranian petroleum, petroleum products and petrochemical products.

Delistings show a path out, but a narrow one. Two tankers, HAKUNA MATATA (IMO 9354167) and PINOCCHIO (IMO 9400112), were removed on 8 October after their sale to non-sanctioned operators; both had been identified in June 2025 as part of Iran's shadow fleet. For ship owners and financiers, the case shows that a vessel's history follows it, and that a sale to non-sanctioned operators preceded removal in these two cases.

Wind-down relief is short-lived. Iran-related General License EE authorized certain transactions necessary to wind down dealings involving Samudra Marine Services and its majority-owned entities until 23 October 2026; that date has passed and no extension was found. General License U expired on 19 April 2026.

Buyers: the teapot refinery pressure point

On 25 April 2026, OFAC designated Hengli Petrochemical (Dalian) Refinery, China's second-largest independent "teapot" refinery, and imposed new sanctions on about 40 shipping firms and vessels alleged to be operating as part of Iran's shadow fleet. OFAC has sanctioned five teapot refineries since the resumption of President Donald Trump's "maximum pressure" campaign on Iran last year.

Beijing pushed back. China announced an injunction to block US sanctions placed on five Chinese refiners, and its foreign ministry said it "opposes unilateral sanctions that have no basis in international law". For firms dealing with the designated refineries, US exposure now sits alongside an open Chinese challenge to those sanctions.

Sources diverge slightly on China's weight in the trade. Treasury cites approximately 90 percent of Iran's oil exports, while another report says Beijing buys more than 80% of Iran's seaborne oil. The two measures differ in scope (total exports versus seaborne), but both indicate extreme concentration.

Traders and banks: front companies and the financial channel

OFAC stated that Iran uses front companies, often in Hong Kong or the UAE, to broker shipments of sanctioned oil to teapot refineries. A secondary source on a June 2026 action reports 12 entities and 6 LPG tankers targeted, naming UAE-based firms such as ADH Energy FZE and Butani Trading LLC as key facilitators; this has not been verified against the Treasury release.

The banking dimension is where exposure is most consequential and least settled. The April alert warned that the department is prepared to deploy secondary sanctions against foreign financial institutions that continue to support Iran's activities, and urged financial institutions to apply enhanced due diligence to Asia- and Middle East-based entities involved anywhere in Iran's oil supply chain to China. Yet Washington stopped short of sanctioning the larger Chinese banks that may facilitate those purchases. The research found no sanctioned major Chinese bank.

A further trap: OFAC FAQ 1249 warns that "toll" payments to the Government of Iran or the IRGC for passage through the Strait of Hormuz are not authorized and are subject to US sanctions restrictions. Voyage-related payments are now a screening point in their own right.

Legislative backstop

The Enhanced Iran Sanctions Act would enact new secondary sanctions on individuals and companies who circumvent sanctions and participate in the illegal sale of oil, liquefied natural gas and petrochemical products coming from Iran. It passed the House Foreign Affairs Committee on a voice vote in April 2025; the research found no evidence of floor passage or enactment, so it is best read as a signal of congressional appetite rather than established law.

Strategic implications

Shippers and owners. Vessel history matters: screen IMO numbers against recent designations and prior shadow-fleet identification, and document ownership changes. Do not rely on expired general licenses.

Traders. OFAC says Iran uses front companies, often in Hong Kong or the UAE, to broker shipments. Enhanced due diligence on counterparties, beneficial ownership and voyage-payment flows is now essential.

Buyers. Teapot refineries are an established target. Any entity supplying, financing or insuring them may inherit part of the risk profile, and China's blocking injunction complicates any simple exit.

Banks. The absence of a major Chinese bank designation is not a safe harbor: Treasury has explicitly warned that it is prepared to use secondary sanctions against foreign financial institutions.

Gaps to monitor. No official list of secondary-sanctions countries, no timelines, and no confirmed enactment of the Enhanced Iran Sanctions Act. Each could change the risk picture quickly.

— InekIA editorial team