The announcement, a financial trend analysis issued by the U.S. agency’s financial crimes enforcement network, stated that the identification was part of U.S. President Donald Trump’s “maximum pressure campaign on Iran,” which it said “will help to ensure financial institutions are tracking and countering the threat posed by Tehran’s shadow banking activity.”

“Identifying Iran’s complex financial lifelines and shadow networks is an essential part of cutting off the funding for their military, weapons programs and terrorist proxies,” stated Andrea Gacki, director of the department’s financial crimes enforcement network.

“By issuing this public analysis, we hope to draw attention to Iran’s shadow banking activity and encourage financial institutions to be vigilant,” Gacki said.

The department said that foreign shell companies, “which exist only on paper with no meaningful business activities,” outside America seem to be responsible for the most transactions (about $5 billion) for the Iranian shadow banking network in 2024.

Dozens of oil companies, which were mostly based in the United Arab Emirates and Singapore and which transacted about $4 billion in 2024, appear to be front companies for Iran. And companies that arranged for Iran to obtain technologies that are illegal to export accounted for about $413 million in 2024, per the department.

The Treasury Department said that Tehran “relies on shadow banking networks of Iran-based exchange houses and foreign companies to evade sanctions, sell oil and other commodities abroad, launder money, sustain its regional terrorist proxies and fund its military and weapons programs.”

Iran’s banking networks connect via the United Arab Emirates, Hong Kong and Singapore, among other places, per the department, and they use a “diverse array of Iranian front companies.”

The array includes oil, shell, shipping, investment and technology procurement companies, “which transact billions of dollars with each other and with unrelated companies, who may be witting or unwitting counterparties,” the department said.