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30.08.2025 18:48

The Index-Linked Circuit Breaker System (EBDKS) will be implemented in a single phase if the BIST 100 Index falls by 5% in the first phase and by 7% or more in the second phase compared to the previous day's closing. It will be activated if the index value declines by 6% or more.

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Borsa İstanbul AŞ announced changes regarding the upper step rule applied in circuit breakers based on shares, the index-based circuit breaker system, and short selling transactions. These changes will be effective as of September 1, 2025.

According to the statement signed by Korkmaz Ergun, General Manager of Borsa İstanbul AŞ, it has been decided to make changes to the Circuit Breaker System based on Shares, EBDKS, and the upper step rule applied in short selling transactions. Accordingly, the decline value of the BIST 100 Index, which is the basis for the implementation of the upper step rule in transaction queues where short selling can be done, will be reduced from 3% to 2% until the end of the session.

EBDKS IS NOW SINGLE-STAGE

Currently, the EBDKS application, which is activated when the BIST 100 Index declines by 5% in the first stage and 7% or more in the second stage compared to the previous day's closing during the day, will be implemented as a single-stage system and will be activated when the index value declines by 6% or more.

TRADING HALT PERIODS HAVE BEEN SHORTENED

The period for entering orders and halting transactions under EBDKS will be shortened by 10 minutes. Accordingly, the 20-minute halt period applied in transaction queues with the feature codes ".E", ".F1", ".F2", ".S1", ".G" in the Equity Market will be reduced to 10 minutes, while the 30-minute halt period applied in transaction queues with the feature codes ".V", ".C", ".F", ".R", ".BE", ".AOF" and in contracts based on shares and share indices traded in the Futures and Options Market will be reduced to 20 minutes.

THE CIRCUIT BREAKER TIME NEAR CLOSING HAS CHANGED

In the equity market, if the Index-Based Circuit Breaker (EBDK) is activated within 60 minutes before the end of the continuous trading session (currently from 17:00), the 60-minute period that serves as the basis for halting transactions and restarting them with the closing session will be applied as 30 minutes (from 17:30).

If the EBDK is activated after 17:30 (currently 17:00) in the Futures and Options Market, transactions in contracts based on shares and share indices will be restarted with the VIOP_SUREKLI_MZYD session at 18:08.

In the equity market, the order collection period after the circuit breaker based on shares will be applied as 10 minutes for all shares traded with the continuous trading method.