New Circuit Breaker System is introduced to our Market by the abolishment of Automatic Circuit Breaker System at 30/11/2015.
In case price change calculated by a certain reference value reaches or exceeds threshold values (rates) determined by the Exchange while transactions in a stock are carried out with continuous trading method in the session, transactions of the related stock will be temporarily halted and carried on to the order collection stage of a call auction.
At this stage price is determined in a call auction using single price method in the related stock. Then the related stock is again taken to continuous trading and transactions are continued after processes single price method are completed.
- Circuit breaker works only in the continuous trading method.
- Circuit breaker reference value as to which rates of price change which will trigger the circuit breaker to be applied, is the price determined with the latest call auction (the price set in the opening session, midday opening session and single opening sessions) or base price of the equity. The latest updated price will be used for circuit breaker reference price.
- Circuit breaker price limits are set by applying 10% margin to circuit breaker reference price.
- Regular transactions continue until these price limits are exercised, however, circuit breaker works and the order which will carry out the transaction exceeding these price limits is cancelled to prevent a transaction outside the price limits. The remaining part is cancelled if mentioned order has carried out transactions with previous price levels.
- Order collection phase of a call auction in the related equity is proceeded after the circuit breaker is triggered. At this phase theoretical price and traded quantity is shown as in the opening/closing and other single price call auctions.
- Matching process comes after order collection period.
- Regular transactions with continuous trading continue after the order collection and matching.
- Duration of the order collection differs due to the market of the equity. 5 minutes order collection and 2 minutes matching is applied for BIST stars. 15 minutes order collection and 2 minutes matching is applied for the equities traded in other markets.
- In BIST stars; if circuit breaker is triggered within 10 minutes to the beginning of midday call auction and closing session (12:50 – 13:00 and 17:50 – 18:00), order collection period is prolonged from 5 minutes to 10 minutes and order collection without matching continues in the following phase. Matching in the related stock occurs following the order collection phase (midday opening or closing session).
- In markets other than BIST Stars; if circuit breaker is triggered within 20 minutes to the beginning of midday call auction and closing session (12:40 – 13:00 and 17:40 – 18:00), order collection period is prolonged from 15 minutes to 20 minutes and order collection without matching continues in the following phase. Matching in the related stock occurs following the order collection phase (midday opening or closing session).
In case circuit breaker is triggered at a stock, trading in the related preemptive rights, warrants, buyin order books continue without any interruption. For example, when circuit breaker is triggered in GARAN.E and this stock is taken to call auction with single price method, trading continues without any interruption in GARAN.R and GADAA.V order books.
Equity Market Department Manager on his own motion can double rates of price change which will trigger circuit breaker on the basis of stock or throughout the whole market, if required within the framework of market conditions. Exchange General Manager on his own motion may remove or change these rates, if required.