The US Treasury Department's sanctions against Turkish banks target illicit channels for converting Iranian oil into cash; Bessant has announced further action next week, which experts say is merely "marginal pressure."

The US Treasury Department's sanctions against Turkish banks target illicit channels for converting Iranian oil into cash; Bessant has announced further action next week, which experts say is merely "marginal pressure."

The Trump administration is launching an "economic offensive" against Iran.

On Friday, June 4 (Eastern Time), the U.S. Treasury Department announced sanctions against Turkish investment bank Golden Global and two of its subsidiaries, accusing them of acting as key intermediaries in Iran’s shadow banking network, assisting in the transfer of Iranian oil revenues to Türkiye and their conversion into cash and gold.

U.S. Treasury Secretary Bessant immediately warned that "another bank may be sanctioned next week," and addressed bad actors in the global financial system: "We know who you are, and you know it yourselves. It's all over." The sanctions add three entities to the Treasury Department's "blacklist"—the Office of Foreign Assets Control's (OFAC) Specially Designated Nationals List—effectively severing their ties with the dollar-based financial system.

This round of sanctions extends the reach of the US financial system from Iran to Turkish financial institutions, marking a comprehensive expansion of the US financial containment of Iran into third-country intermediaries and posing a potential impact on Turkish banking and lira assets.

Details of the allegations: The middleman chain of oil revenues

According to reports, the U.S. Treasury Department stated that Golden Global Investment Bank, also known as Golden Global Yatirim Bankasi Anonim Sirketi, was designed to serve Iran's shadow banking network by transferring Iranian oil revenues to Turkey, where they were then converted into cash and gold by currency exchangers.

The U.S. Treasury Department further accused Golden Global of knowingly and deliberately providing agent banking services to Iranian financial institutions, enabling funds to flow through accounts controlled by the Quds Force of the Islamic Revolutionary Guard Corps and its agents.

The three entities sanctioned are: Istanbul-based Golden Global Yatirim Bankasi Anonim Sirketi (the investment bank itself), asset management firm Golden Global Portfoy Yonetimi Anonim Sirketi, and asset leasing firm Golden Global Varlik Kiralama Anonim Sirketi.

All three entities have been placed on OFAC's Specially Designated Nationals List and their dollar settlement channels have been cut off. The Treasury Department has also issued general licenses, allowing relevant parties to orderly settle existing transactions with these entities during the transition period.

According to data from TheBanks.EU, Golden Global Investment Bank is the 35th largest bank in Turkey by assets, with total assets of approximately 25.025 billion Turkish lira (approximately US$517 million) in 2025. As of press time, the bank had not responded to requests for comment.

Bessant warns: Weekly sanctions will become the norm

In an interview with US media, Bessant used strong language, characterizing the sanctions as "a signal that you're shutting down." In an interview with Reuters, he further stated that the Treasury Department might roll out new secondary sanctions weekly, initially targeting the banking sector, as part of a broader effort to increase pressure on Iran.

Last month, Bessant announced an "economic offensive" against Iran's global financial network and made it clear that Washington's goal is to force Tehran back to the negotiating table.

Last week, the U.S. government invoked provisions of the Patriot Act to restrict Banque Misr's branch in the UAE from participating in dollar transactions, citing its ties with Iran. However, this action did not reach the level of full OFAC sanctions and did not affect Banque Misr's headquarters or other branches. The sanctions against Golden Global are significantly more severe, with Bessent directly labelling it as "out of the game."

Geopolitical signals: Third-country financial intermediaries become new targets of attack

The deeper significance of these sanctions lies in the fact that the United States is extending its financial containment of Iran beyond its borders, with Turkish financial institutions bearing the brunt. This move serves as a direct warning to the Turkish banking sector—any institution with financial dealings with Iran faces the risk of being added to the OFAC list and losing its dollar clearing eligibility.

The military conflict between the US and Iran has now lasted for six months, driving up global energy prices. Against this backdrop, Bessant's statement about "alliance assistance" also suggests that the US is seeking to build a broader multilateral sanctions coordination mechanism.

The Turkish government has not yet publicly responded to the sanctions. Given the long-standing trade and economic ties between Turkey and Iran, and Turkey's complex relationship with the United States within the NATO framework, Ankara's subsequent statements will be closely watched by the market.

The effectiveness of market and policy measures remains questionable.

Brett Erickson, a sanctions expert and managing director at Obsidian Risk Advisors, questioned the actual effectiveness of the action. He stated that sanctioning Golden Global would only "marginally increase pressure on Iran" and warned that the move could provoke retaliation from the Iranian government.

“Harming Iran and changing the course of this war are two very different things,” Erickson said. “If this pressure fails to substantially change the economic course of the war, Washington may just be stirring up a hornet’s nest and instead encourage Iran to retaliate in ways that could cause even greater damage to the global economy.”

For investors, Bessant's statement of "weekly sanctions" means that related uncertainties will persist. Turkish lira assets and financial institutions with business ties to Iran will face increased compliance scrutiny and market volatility risks in the short term.

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