BIST 100 Slumps Past 2% Trigger, Istanbul Stock Exchange Enforces ‘Uptick Rule’ on Short Sales

Istanbul’s Borsa İstanbul invoked the ‘uptick rule’ on short‑sellable stocks after the BIST 100 index slipped more than 2%, restricting any short sale below the last traded price for the remainder of the session.

Short‑Sale Curb: The ‘Uptick Rule’ in Action

■The rule prohibits entering a short position at a price lower than the last executed trade.

■Triggered at 16:44 local time when the BIST 100 loss breached the 2% threshold.

■Remains in force until market close and applies only to securities eligible for short selling.

Market Reaction and Liquidity Impact

■Designed to dampen accelerating sell‑offs and curb intraday volatility.

■Mirrors the SEC’s historic uptick rule and similar bans in European jurisdictions.

■Analysts estimate a short‑sale volume dip of 15%‑20%, with only a marginal effect on longer‑term liquidity.

Historical Precedents and Outlook

■During the March 2020 pandemic shock, BIST imposed temporary short‑sale bans.

■Such interventions typically cut volatility by 10%‑15% but can delay price discovery.

■For sustainable market health, focus on fundamentals and transparency‑enhancing reforms remains paramount.

Dr. Aslıhan Demir: 'The uptick rule is an effective short‑term tool to curb panic selling, yet it can sap liquidity and blunt the price‑formation process. To reveal the market’s true direction, policymakers must prioritize macro data and corporate earnings.'