Yunus Arinci, chief executive of Turkey's clearing and custody bank Takasbank, has reportedly resigned after being questioned by prosecutors investigating alleged market manipulation linked to the country's investment fund crisis, according to a report by Bloomberg.

Arinci was questioned over the weekend before being released, according to people familiar with the matter. His reported departure comes amid mounting scrutiny of Turkey's capital markets institutions, following the detention of Borsa Istanbul chief executive Korkmaz Ergun on allegations of bribery and membership in a criminal organisation. Ergun also serves as deputy chairman of Takasbank.

The developments follow a major investment fund crisis in September, when several funds were unable to meet investor redemption requests. Regulators subsequently ordered the liquidation of 131 funds managed by seven asset managers, affecting more than 455,000 investors and raising concerns over liquidity management and market oversight.

Turkey's government has also reshuffled the leadership of its Capital Markets Board, appointing Muhsin Atci, previously head of the country's tax inspection authority, as chairman. He replaces Mahmut Sutcu, who was removed in October after approximately five months in the role. Former chairman Ibrahim Omer Gonul, who had previously been questioned in connection with the investigation, has also been removed from a subsequent regulatory position.

Takasbank plays a central role in Turkey's financial markets, providing clearing, settlement and custody services for transactions involving brokers, institutional investors and Borsa Istanbul.

The widening investigation has intensified uncertainty surrounding Turkey's investment fund industry, highlighting concerns over regulatory oversight, fund liquidity and investor protection as authorities examine allegations of market misconduct.