The U.S. Treasury Department has expanded economic pressure on Iran by designating 17 additional vessels that it says are connected to Tehran’s shadow fleet. The action is designed to further restrict Iran’s ability to transport and monetize crude oil, petroleum and petrochemical products as Washington seeks to weaken the financial channels supporting the Iranian government.

Washington Targets Iran’s Maritime Oil Network

The new designations are part of Operation Economic Outcast, the U.S. campaign aimed at increasing economic pressure on Iran. Treasury said the newly sanctioned vessels operate under more than a dozen jurisdictions and have transported millions of barrels of Iranian crude, petroleum and petrochemical products.

Treasury Secretary Scott Bessent said the department would continue targeting entities that facilitate Iranian oil sales and sanctions evasion. The latest vessels are all newly designated, with Treasury describing the action as an effort to target remaining elements of Iran’s shadow fleet and reinforce existing sanctions.

Vessels Linked to Millions of Barrels

The designated vessels include several tankers that Treasury says have played significant roles in transporting Iranian energy products. The Vanuatu-flagged TINA 5, for example, reportedly transported more than 1.5 million barrels of Iranian crude in August.

The Comoros-flagged LPG tanker SOGL has allegedly moved more than two million barrels of Iranian propane and butane since September 2025. Treasury also identified the Cameroon-flagged crude tanker SHENZHEN, which it says transported more than 3.5 million barrels of Iranian crude since November 2025.

The scale of those reported shipments illustrates why tanker networks remain a central focus of U.S. sanctions policy. Restricting individual vessels can increase the difficulty and cost of moving Iranian petroleum even when broader export infrastructure remains available.

Iranian Oil Flows Face Additional Pressure

A Treasury official said Iran has stopped loading and offloading oil because of the ongoing U.S. blockade of its ports. Kpler data cited in the source material indicates that Tehran had not loaded crude oil for export since Aug. 25.

If sustained, such disruptions could have consequences beyond Iran’s domestic economy. Restrictions on Iranian exports can alter regional supply patterns and increase sensitivity to any additional disruption affecting Gulf shipping routes. However, the 17-vessel designation alone is not expected to fundamentally transform Iran’s economy, according to the source material.

Hormuz Remains a Critical Energy Risk

The sanctions come against the backdrop of severe disruption to global energy markets caused by the conflict involving Iran and instability around the Strait of Hormuz. The waterway is one of the most important routes for transporting oil and gas from the Gulf, making any restriction on maritime traffic particularly significant for energy consumers and producers.

Oil and gas prices have experienced substantial volatility as Iran has sought to restrict traffic through the Strait. The effects are also reaching consumers directly, with U.S. gasoline prices rising sharply. The national average stood at $4.36 per gallon on Thursday, according to the source material.

What the Sanctions Could Mean for Oil Markets

The immediate market impact of the latest designations will depend on whether they materially reduce Iran’s ability to move remaining export volumes or simply redirect shipments toward alternative vessels and routes. The broader pressure campaign is more consequential when combined with restrictions on ports, previous sanctions and disruptions around Hormuz.

For energy markets, the next signals to watch will be Iranian export-loading activity, tanker movements and the availability of alternative Gulf supplies. If Iranian exports remain constrained while maritime risks persist, the energy market could retain a significant geopolitical risk premium. Conversely, any restoration of normal shipping and export activity could reduce some of that pressure.