Trading had to be halted in Indian markets for 45 minutes today after Nifty50 index crashed 10% in early trade. This is first time in 12 years trading in Indian markets had to be halted. The market-wide circuit breaker system of BSE and NSE applies at three stages of the index movement, either way at 10%, 15% and 20%. These circuit breakers bring about a coordinated trading halt in all equity and equity derivative markets nationwide.

The market-wide circuit breakers are triggered by movement of either the BSE Sensex or the Nifty 50, whichever is breached earlier.

After a trading halt, markets re-open after index based market-wide circuit filter breach, with a pre-open call auction session. A 15-minute pre opening session post each trading halt is held, unless trading is halted for the remainder of the day.

The trigger limits and the respective halt duration is given below:

10% movement before 1 pm - trading halt of 45 minutes

10% movement at or after 1 pm to 2.30 pm - trading halt of 15 minutes

10% movement at or after 2.30 pm - no halt

15% movement before 1 pm - trading halt of 1 hour 45 minutes

15% movement At or after 1 pm before - trading halt of 2 pm 45 minutes

15% movement - On or after 2 pm - Trading halt for the remainder of the day

20% movement any time of the day - Trading halt for the remainder of the day

BSE and NSE compute the index circuit breaker limits for 10%, 15% and 20% levels on a daily basis based on the previous day's closing level of the index rounded off to the nearest tick size.