The United States Treasury Department announced fresh sanctions on Thursday against Greek shipping magnate Antonios Margaritis and a web of companies he oversees in Greece and the Marshall Islands, accusing them of facilitating the transport and sale of Iranian oil. The action broadens the Trump administration’s maximum-pressure campaign against Tehran and its effort to dismantle Iran’s so-called “shadow fleet.” According to Treasury officials, Margaritis “leveraged his decades of experience in the shipping industry to illicitly facilitate the transportation and sale of Iranian petroleum.”

Sanctioned Companies And Network

Among the firms targeted were Marant Shipping and Trading S.A., Square Tanker Management Ltd., Comford Management S.A., and United Chartering S.A. These companies are alleged to have played roles in transporting Iranian petroleum in violation of U.S. sanctions. The designation aims to cut off access to international financial systems and complicate efforts by Iran to sustain oil exports through third-party networks.

Broader Context Of US Pressure

The measures follow Washington’s largest Iran-related sanctions in seven years, which earlier targeted an oil trading network linked to Hossein Shamkhani, son of a senior adviser to Supreme Leader Ayatollah Ali Khamenei. The new sanctions signal continued U.S. focus on disrupting Iranian oil shipments amid Tehran’s attempts to maintain production despite ongoing restrictions.