U.S. Treasury Sanctions 17 Vessels, 18 Firms in Crackdown on Iran's 'Shadow Fleet'

The U.S. Treasury Department on Thursday sanctioned 17 vessels and 18 related companies that it said make up Iran’s remaining “shadow fleet,” the latest enforcement step in a broader campaign to squeeze the country’s oil revenue.

In an Oct. 8 announcement, Treasury said the action was carried out by its Office of Foreign Assets Control, or OFAC, under Operation Economic Outcast, a wider U.S. sanctions drive against Iran and its commercial enablers that the department announced Aug. 24. Treasury said the vessels were used to transport Iranian crude oil, petroleum products and petrochemical products to buyers in South and East Asia.

The move matters because it is aimed not just at ships but at the web of shipping, management and trading firms that help keep Iranian energy exports moving outside normal commercial channels. Treasury also used the action to warn banks and other intermediaries that doing business with the newly designated network could expose them to U.S. penalties, including so-called secondary sanctions.

Treasury said the designations were made under Executive Order 13902, the authority the United States uses to target people and companies operating in designated sectors of Iran’s economy. OFAC updated its Specially Designated Nationals and Blocked Persons list, known as the SDN list, to add the vessels and entities involved in the action.

The practical effect is broad. Treasury said any property or interests in property of the designated persons that are in the United States, or in the possession or control of U.S. persons, are blocked and must be reported to OFAC. U.S. persons are generally prohibited from transactions with the designated persons unless authorized. Treasury also said any entity owned 50% or more, directly or indirectly, by one or more blocked persons is itself considered blocked.

Treasury paired those restrictions with a warning to overseas financial institutions. In its release, the department said foreign banks that knowingly facilitate certain significant transactions involving the newly designated persons could face secondary sanctions or restrictions on their correspondent accounts in the United States.

The package also included a narrower sign that sanctions relief is possible when ownership or use changes. OFAC removed two vessels from the SDN list — HAKUNA MATATA and PINOCCHIO — after what Treasury described as a demonstrated change in circumstances, including their sale to non-sanctioned, U.S.-aligned operators. That suggests Treasury is trying to show there is an off-ramp for ships that leave the sanctioned trade network.

A “shadow fleet” generally refers to ships used to move sanctioned oil outside standard commercial systems, often through tactics such as front companies, reflagging, frequent name changes, ship-to-ship transfers and false paperwork. The Oct. 8 action fits into a broader 2025-2026 U.S. sanctions campaign targeting Iranian oil shipping and petrochemical trade under Operation Economic Outcast.

Treasury cast the measure as a major blow to that network, saying, “Today’s action effectively neutralizes the vast majority of Iran’s remaining shadow fleet network.”