By Bosphorus News Economy Desk
On November 9, 2026, an İstanbul court ordered the pretrial detention of Muhammet Erişen, deputy chairman of Türkiye's Banking Regulation and Supervision Agency (BDDK), and Murat Yönaç, general manager of Adil Katılım Bankası. Police later detained OMG Capital Advisors chairman Ömer Murat Gülkan and Lydia Holding chairman Enver Çevik in the same investigation into fund and stock-market transactions.
Erişen is the highest-ranking serving BDDK official reported arrested in the case. Yönaç previously held the same position. Proceedings had already involved officials at the Capital Markets Board (SPK), Borsa İstanbul and Takasbank.
Arrests Reach BDDK Leadership
Erişen and Yönaç were questioned by prosecutors before a criminal judgeship of peace ordered them held pending investigation. BDDK Implementation Department 4 head Mustafa Alper Taş and Implementation Department 3 head Bilal Soysal had been remanded in custody in the preceding days. Public accounts of the hearings have not identified the transactions or regulatory decisions attributed to either man.
According to the Participation Banks Association of Türkiye, Yönaç left the BDDK in January 2023 while serving as deputy chairman. He became Adil Katılım Bankası's general manager on March 18, 2025. His former position does not establish involvement in the transactions under investigation.
Anadolu Agency reported Gülkan's detention on Monday evening. Enver Çevik was detained earlier that afternoon, having been questioned and released in September. In the latest available reports, former Takasbank general manager Yunus Arıncı, Bulls Yatırım chairman Kemal Akkaya and Ruzy Madencilik chairman Nureddin Çevik were still being questioned by police. No later court decisions on the five executives had been confirmed.
In Bloomberg's October 21 investigation, Gülkan criticized regulatory oversight and referred to reports of pressure on people who had raised concerns about certain funds. The allegations behind his detention have not been disclosed in the available reporting. No verified record connects his earlier comments to the custody decision.
Minister Reports 464 Suspects
Justice Minister Akın Gürlek told parliament's Planning and Budget Committee on November 9 that the investigation involved 464 suspects: 120 in pretrial detention, 262 under judicial-control measures and 40 fugitives subject to arrest warrants. He also reported asset restraints affecting 386 individuals and 116 legal entities.
On November 3, Gürlek had reported 433 suspects, 112 in custody, 186 under judicial control and 38 fugitives. The November 9 figures preceded reports of Gülkan's and Çevik's detentions later that day.
Gürlek said investigators were tracing money and asset transfers. The arrests of senior BDDK officials have also brought banking supervision into the inquiry. Earlier proceedings involving stock-exchange and clearing officials are covered in the earlier Borsa İstanbul and Takasbank investigation.
TL31.6 Billion in Returns, Separate Investor Payments
The Savings Deposit Insurance Fund (TMSF) said on November 9 it had collected TL31.6 billion through voluntary returns linked to funds in liquidation and shares heavily traded by those funds. Its review extends to people who made unusually large inflation-adjusted gains on those shares, even if they never owned fund units. The agency plans to lower the gain thresholds in stages to examine more transactions.
Gürlek put the value of returned money, real estate and shares at approximately TL31.5 billion. The published statements do not explain the difference from the TMSF's TL31.6 billion, or establish that the figures represent separate recoveries.
SPK rules published on October 1 provide for dedicated return accounts for each affected fund and a general account for proceeds from share transactions. Fund-specific returns enter the assets available for liquidation. TMSF said voluntary repayment does not establish criminal liability; suspected offences are investigated separately.
Investor payments are accounted for separately. Treasury and Finance Minister Mehmet Şimşek reported on November 5 that TL130.2 billion had been distributed across 108 funds to 614,874 accounts belonging to 420,031 people. Of those investors, 179,449 had recovered their full net invested amount. The distributions draw on fund assets and recovery mechanisms, including voluntary returns, so the TL130.2 billion and TL31.6 billion figures must not be added together.
Tera Holding Faces Separate Creditor Action
Bailiffs visited Tera Holding AŞ's İstanbul offices on November 9 over a reported TL1.2 million creditor claim. Lawyer Emre Burak Onat, representing the claimant, told Demirören News Agency that seizure measures had been placed on company bank accounts and two vehicles. He was also seeking to carry out a physical seizure at the premises. The enforcement file was not available for independent review. The creditor action is separate from the criminal investigation, the trustee appointment and the fund liquidations.
Regulatory Warnings Predated the Arrests
The SPK ordered 131 funds managed by seven portfolio management companies into liquidation following its September 17 intervention. Earlier, MSCI's warnings and the pricing of low-float shares had raised concerns about concentrated holdings and unusual price movements. Those warnings preceded the investigation; they do not establish wrongdoing by the people now detained.
Prosecutors have yet to disclose the specific supervisory decisions under examination. TMSF has not published how the TL31.6 billion is divided between individual fund accounts and the general share-return account.
Sources: Türkiye's Ministry of Justice, Savings Deposit Insurance Fund, Capital Markets Board of Türkiye, Participation Banks Association of Türkiye, Turkish Grand National Assembly proceedings, Anadolu Agency, Demirören News Agency, Bloomberg, Ekonomim, Bosphorus News review and reporting.