Borsa Istanbul will remove more than a quarter of the BIST 100 in its largest reshuffle in six years. The exchange is applying new volatility and equity-size requirements for admission to the Star Market, which is itself a prerequisite for the BIST 30 and BIST 100. The change follows the concentrated-fund liquidity crisis that led regulators to freeze trading and order the liquidation of 131 funds. Reuters, September 22
Changing the index does not create liquidity in the underlying shares, but it changes forced demand from passive and benchmark-aware money. Removing thin, volatile constituents makes the headline benchmark healthier by construction and shifts some of the adjustment onto holders tracking it. That is preferable to preserving an index whose membership validates fragile prices, although the rebalance itself may concentrate selling in the names the new rules are meant to quarantine.