Levent Kenez/Stockholm
The United States Treasury Department blacklisted a Turkish bank and its two subsidiaries on September 4, accusing the lender of helping Iran’s Islamic Revolutionary Guard Corps (IRGC) Quds Force move tens of millions of dollars through Turkey’s financial system, the latest move in a growing US campaign targeting Turkish financial institutions over alleged sanctions violations, a number of years after the United States brought a criminal case against a state-owned Turkish bank and repeatedly targeted a businessman close to Turkish President Recep Tayyip Erdogan.
The Office of Foreign Assets Control( OFAC) designated Istanbul-based Golden Global Yatırım Bankası Anonim Şirketi along with two affiliates, Golden Global Varlık Kiralama Anonim Şirketi and Golden Global Portföy Yönetimi Anonim Şirketi. Treasury said the bank was established to move Iranian oil revenue earned from sales to China back into Turkey, where it was converted into cash and gold through a network known as the Rahbar money exchange operation, then routed onward to the IRGC and its proxies.
According to Treasury’s designation notice, Golden Global Bank knowingly provided correspondent banking access to Iranian financial institutions, enabling transactions through accounts tied to Turkish businessman Sıtkı Ayan and his companies. Ayan and his network were sanctioned by OFAC in 2022 for moving hundreds of millions of dollars connected to Quds Force oil sales.
The Golden Global case is not an isolated action against Turkey’s banking sector. Halkbank, majority owned by the Turkish state, was at the center of a much larger sanctions-busting scheme that first became public in December 2013, when Turkish police raided the home of its general manager, Süleyman Aslan, and found shoeboxes stuffed with cash. Prosecutors later said the bank had helped Iran evade US sanctions through a multibillion-dollar gold-for-oil-and-gas scheme engineered by Turkish-Iranian gold trader Reza Zarrab, who used Halkbank accounts and front companies to let Iran access its oil and gas revenue despite being locked out of the international banking system.
The December 2013 investigation implicated the sons of three cabinet ministers along with Aslan, and Zarrab was recorded in wiretaps discussing bribes with then-economy minister Zafer Çağlayan. Erdogan, then prime minister, dismissed the investigation as a coup attempt against his government and reassigned or dismissed the police and prosecutors handling the case, with the domestic investigation shut down without charges. Zarrab was later arrested in Miami in 2016 and, after initially fighting extradition, pleaded guilty and became a cooperating witness for US prosecutors in the Southern District of New York. Testifying in the 2017 trial of Halkbank’s deputy general manager, Mehmet Hakan Atilla, Zarrab said Erdogan had personally authorized the scheme while serving as prime minister.
Halkbank itself was indicted in 2019 on charges of bank fraud, money laundering and conspiracy tied to the transfer of roughly $20 billion in restricted Iranian funds. It fought the case for years on grounds of sovereign immunity, a defense the US Supreme Court rejected in October 2025, clearing the way for trial. Rather than proceed to trial, the Justice Department and Halkbank reached a deferred prosecution agreement in March 2026 that barred the bank from conducting transactions benefiting Iran and required it to hire an outside monitor to review its sanctions compliance. In June 2026, after an independent review found the bank’s compliance program satisfactory, US District Judge Richard Berman granted the government’s motion to dismiss the case with prejudice, formally closing the prosecution after nine years. The Justice Department cited Turkey’s role in negotiating the October 2025 Gaza ceasefire and hostage releases as context for the resolution, and Halkbank stated that the case had been definitively and conclusively closed.
Separately, under aviation sanctions announced in September 2026, OFAC designated three Turkey-based companies accused of supporting Iran’s Mahan Air, which the US has long linked to the Quds Force’s logistics network. İzmir-based Sky Phoenix was accused of brokering the transfer of three Boeing 777 aircraft to Mahan Air. Istanbul-based S Sistem Lojistik was accused of coordinating shipments of drone components to Iran. Istanbul-based Mes Cargo was designated for allegedly running Mahan Air’s general sales agency operations inside Turkey.
Ayan, a businessman born in Sivas who studied theology before moving into the oil trade, has been a recurring figure in US sanctions actions and Turkish political controversy for more than a decade. Treasury’s 2022 designation said Ayan brokered international sales contracts for hundreds of millions of dollars’ worth of Iranian oil to buyers in China, East Asia, the United Arab Emirates and Europe; arranged shipping for the oil; and funneled proceeds back to the Quds Force. His Gibraltar-registered ASB Group, along with roughly 20 affiliated companies, his son Bahaddin Ayan and his longtime associate Kasım Öztaş were sanctioned in the same action. Then-secretary of state Antony Blinken said at the time that Ayan had for years supported both the Quds Force and Hezbollah. Ayan said he had only ever worked with Iran’s official government institutions.
On February 2, 2024, federal prosecutors in the Southern District of New York indicted Ayan along with six others, including Iranian Quds Force general Behnam Shahriyari, on charges of terrorism financing, sanctions evasion, fraud and money laundering tied to oil sales funneled through China, Russia and Syria. Shahriyari, who court filings say built the Quds Force’s Turkish network under the alias Sayed Ali Akber Mir Vakili while claiming diplomatic status, was put under surveillance by Turkish counterterrorism police before being killed in an Israeli airstrike in western Iran on June 21, 2025.
Ayan’s ties to Turkey’s ruling circle stretch back to the 2000s, when his company Som Petrol signed a $1 billion deal in 2010 to build a pipeline that would carry Iranian gas through Turkey, a project supported by the Turkish government. His Turang Transit venture received what was then the second-largest state investment incentive in Turkish history, approved on December 16, 2013, one day before Turkish police launched a sweeping corruption and bribery investigation targeting figures around the government.
Ayan’s name surfaced directly in that investigation. According to leaked wiretap recordings from the corruption probe, Ayan had promised a payment to then-prime minister Erdogan, but delivered an initial installment worth $10 million that fell short of the amount agreed. In one of the recordings, an angry Erdogan is heard discussing the shortfall with his son, Bilal Erdogan, saying of Ayan and the money he owed, “They will fall into our lap,” a phrase reported at the time as a warning that Ayan would be made to answer for it. Kemal Kılıçdaroğlu, then-leader of Turkey’s main opposition party, cited Ayan by name when he alleged in parliament that Erdogan and his family had funneled money to offshore companies linked to Ayan registered in the Isle of Man.
WikiLeaks cables from the US Embassy in Ankara from the same period documented Erdogan’s direct involvement in advancing the Iran-Turkey gas pipeline arrangement that Ayan’s companies went on to build.
Ayan has built and dissolved dozens of companies over the years, records from the Istanbul Chamber of Commerce show, including firms tied to the 2010 Iran pipeline deal, a 2009 contract to import Iranian electricity into Turkey and the ASB Group structure later sanctioned by Treasury. Iran’s Quds Force remains designated by the US as a terrorist organization, and Washington has levied sanctions on Iran continuously since the Trump administration withdrew from the 2015 nuclear agreement in 2018.
In an unusual move to head off any strain in relations between the two NATO allies, US Ambassador to Turkey Tom Barrack issued a statement seeking to put the September 4 designation “in its proper context,” stressing that the measure targeted the conduct of one financial institution and not Turkey as a nation or its banking system as a whole. The statement suggested Washington did not view the case as the opening of a new Halkbank-style ordeal, while at the same time making clear that Turkish authorities had engaged with US officials to address the ambiguities involved, an acknowledgment that Treasury holds a broader set of pending cases and files, in the mold of Halkbank, that it could still act on.
