By Bosphorus News Economy Desk
Türkiye's banking regulator has revoked the operating license of Iran's Bank Mellat in Istanbul, two days before Iranian carrier Mahan Air ends its flights to Turkish airports.
The Banking Regulation and Supervision Agency (BDDK) adopted decision number 11572 on September 18. Published in the Official Gazette on September 19, the decision covers the Bank Mellat Istanbul Türkiye Central Branch.
Mahan Air will operate its final flights between Tehran and Istanbul and Ankara on September 20. Services are suspended from September 21 until further notice.
BDDK Chose Revocation Over Transfer
The BDDK based its decision on Article 71(1)(b) of Banking Law No. 5411. The provision applies when the continuation of a bank's activities would endanger the rights of depositors and participation fund holders or the security and stability of the financial system.
Article 71 allows the regulator to revoke an operating license or transfer shareholder rights excluding dividends, together with management and supervision, to the Savings Deposit Insurance Fund (TMSF). For Bank Mellat, the BDDK chose revocation.
The notice gives no details of the findings behind that decision. Reuters reported that it contains no reference to US sanctions or operational problems. It also does not explain how deposits and other obligations at the Istanbul branch will be handled.
Bank Mellat received permission to operate in Türkiye under a Council of Ministers decision dated February 5, 1981. Its Istanbul branch opened on April 16, 1982, and branches later opened in Ankara and İzmir.
The lender remains under US, European Union and UK sanctions. Washington first designated Bank Mellat under proliferation authorities in 2007 and separately under counterterrorism authorities in 2018. The Iranian government is its largest shareholder, according to current European Union sanctions records.
Bosphorus News found no public response from Bank Mellat or the Iranian government by publication time.
US Treasury Says Mahan Halt Followed Talks With Ankara
Mahan Air said its suspension followed directives from the relevant aviation authorities in Türkiye, according to IranWire. Ankara has published no decision. Reuters also reported that neither Türkiye nor Oman had publicly announced their measures.
Turkish officials told Middle East Eye that the move followed US sanctions on companies in Türkiye providing services to Mahan Air. They said it should not be read as a broader ban on Iranian carriers.
The officials said Türkiye would continue reviewing other Iranian airlines, citing the bilateral aviation agreement with Tehran, flight safety and the possibility of further US sanctions on companies in Türkiye. Mahan operated at least three daily flights between Istanbul and Tehran.
The US Treasury Department linked the decisions in Türkiye and Oman to discussions over compliance with US measures against Iran, Reuters reported. A Treasury spokesman thanked both governments. Oman halted Mahan's Muscat route on September 17, while flights to Georgia are due to stop on September 21. Reuters also placed the Bank Mellat decision within Washington's broader push for tighter enforcement of measures against Iran.
Three Turkish Firms Named in Aviation Package
The Office of Foreign Assets Control (OFAC) sanctioned 36 targets on September 8 under Operation Economic Outcast, including 27 Iranian airlines. Three targets are based in Türkiye.
Treasury accused İzmir-based Sky Phoenix Hava Yolları Taşımacılığı and UAE-based ECT Aviation Support of acting as intermediaries in the transfer of at least three US-origin Boeing 777 aircraft to Mahan Air in summer 2026. The aircraft were routed through the United Arab Emirates and Oman.
It also said Istanbul-based S Sistem Lojistik coordinated shipments for Mahan Air, including unmanned aerial vehicle components and industrial equipment bound for Iran. Istanbul-based Mes Cargo was identified as a general sales agent for the airline.
S Sistem rejected Treasury's allegations and said it had permanently ended all indirect logistics and operational relationships with Mahan Air as of September 9. Bosphorus News found no public response from Sky Phoenix or Mes Cargo by publication time.
The same September 8 package included an alert from Treasury's Financial Crimes Enforcement Network (FinCEN) asking financial institutions to report procurement networks supporting Iran's aviation sector. Treasury Secretary Scott Bessent warned that companies dealing with Iran's remaining airlines risk being "cut off from the global financial system."
Second BDDK Decision in a Week
Bank Mellat is the BDDK's second Iran-related decision within a week.
Under decision number 11569 on September 16, the regulator gave the TMSF the right to exercise all shareholder rights except dividends over 99.98% of Golden Global Yatırım Bankası. The decision covers the stakes of Emir Kaya at 53.98%, Salih Berberoğlu at 32% and Recep Kaba at 14%. It was taken under Article 18(5) of the Banking Law and does not transfer ownership of the shares.
Washington sanctioned Golden Global and two subsidiaries on September 4, alleging that the bank helped move Iranian oil revenues and provided accounts linked to the Islamic Revolutionary Guard Corps (IRGC) with correspondent banking access. The bank denies the allegations. OFAC's wind-down license for transactions with Golden Global expired at 12:01 a.m. Eastern Daylight Time on September 19.
US Ambassador to Türkiye Tom Barrack said on September 5 that Treasury and Turkish counterparts had been in direct and continuous contact during the process. He called the Golden Global sanction a "narrow measure" and said it should not be interpreted as a judgment on Türkiye.
Four US Actions Reach Türkiye
Since August 24, four Operation Economic Outcast actions have included targets or entities linked to Türkiye.
The first targeted four Istanbul companies over Iranian petrochemical imports. Golden Global followed on September 4, and the September 8 aviation package named Sky Phoenix, S Sistem and Mes Cargo.
OFAC added another Türkiye link on September 10 when it designated Amir Al-Makansi. Treasury described him as operating a Syria-based gold exchange with offices in Istanbul on behalf of a US-designated Hezbollah financier. OFAC also adopted a presumption of denial that day for most Iran-related license applications.
Measures Precede Erdoğan-Trump Meeting
The decisions have fallen into a narrow window before a planned meeting between President Recep Tayyip Erdoğan and US President Donald Trump on the sidelines of the United Nations General Assembly in New York. Barrack announced the meeting on September 17, one day after the BDDK's Golden Global decision and one day before the regulator revoked Bank Mellat's license.
The sequence runs from the September 16 Golden Global measure to Barrack's September 17 announcement, the Bank Mellat decision on September 18 and its publication on September 19, followed by Mahan Air's final Türkiye flights on September 20 and suspension from September 21.
Bosphorus News found no public statement from Turkish or US officials linking the banking and aviation decisions to the Erdoğan-Trump meeting. The measures nevertheless come after acknowledged contacts between US and Turkish officials over Golden Global and after the US Treasury linked the Mahan halt to discussions with Türkiye over enforcement of US measures against Iran.
Türkiye has so far acted through regulatory decisions and aviation instructions, without a corresponding ministerial explanation. Bosphorus News found no public statement from the Foreign Ministry, Treasury and Finance Ministry, Trade Ministry or Transport and Infrastructure Ministry addressing the Bank Mellat, Mahan Air or Golden Global decisions by publication time.
Sources: US Department of the Treasury, Office of Foreign Assets Control, Financial Crimes Enforcement Network, Banking Regulation and Supervision Agency, Official Gazette of the Republic of Türkiye, Council of the European Union, UK Sanctions List, US Embassy in Türkiye, S Sistem Lojistik, Middle East Eye, Reuters, IranWire, Bosphorus News review and reporting