Turkey's Borsa Istanbul to overhaul BIST 100, swapping over a quarter of constituents

Borsa Istanbul announced an extensive revision of the BIST 100 index, removing over a quarter of its constituents starting next month, the most significant adjustment since market-structure reforms were enacted six years ago. Companies slated for removal include Destek Finans Faktoring, Katılımevim, Esenboğa Elektrik, Işıklar Enerji Yapı Holding and Odine Teknoloji, while Anadolu Grubu Holding and fast-food retailer TAB Gıda will return after a prior exclusion.

The move follows regulator actions to stabilize the market after a liquidity crunch in investment funds triggered an 8% plunge in the index last week, prompting forced fund liquidations and investigations into redemption defaults. New guidelines also revise free-float calculations, excluding certain fund holdings, and impose stricter Star Market eligibility criteria, capping volatility at 10% and requiring median-level equity. Analysts such as Onurcan Bal and Cemal Demirtaş expect the reshuffle to foster healthier price formation and rebuild confidence in Turkey’s equity benchmarks.