BIST 100 Triggers New Short‑Selling Rule After Falling Over 2%: Up‑Step Applied Until Session Close

A sudden ‑2% slide in the BIST 100 index has activated a fresh short‑selling protocol at Borsa Istanbul, signaling a shift in short‑term liquidity management.

Critical Threshold Breached on BIST 100

At 10:51:32, the BIST 100 index crossed the ‑2% barrier, automatically triggering the exchange’s short‑selling safeguards for the equity market.

New Short‑Selling Protocol: The Up‑Step Rule

BIST will enforce an up‑step rule until the session’s end. Under this rule, traders with short positions must wait for the price to rise by a predefined increment before they can close their positions; otherwise, the trade is automatically terminated.

Implications for Market Participants

■Liquidity pressure: Short‑selling pressure may intensify, raising volatility.

■Risk management: Fund managers and brokerage houses need to reassess position limits.

■Price dynamics: The up‑step rule could induce sharp price rebounds.

■Regulatory precedent: A similar threshold was applied in 2022, but this time the enforcement window extends to the session close.

Operational Details and Timeline

■Enforcement window: Effective from the trigger moment until the close of the same trading day.

■Monitoring system: Real‑time data feeds will log threshold breaches instantly.

■Communication channel: The announcement was published on the Public Disclosure Platform and emailed to all licensed intermediaries.

Kerem Tufan – Director of Commercial Loans and Central Bank Policies: "While micro‑regulations like this aim to preserve market depth and curb excess volatility, we must monitor their indirect impact on SME financing. A tightening of credit liquidity could dampen risk appetite; consequently, banks should revisit their liquidity‑management strategies."