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Sebi has revised the rules for circuit breaker-induced trading halts for India's two main equity indexes, aiming to contain volatility.
Stock exchanges would now calculate 10%, 15% and 20% circuit breaker limits of market-wide index variation based on the previous day's closing levels on the Sensex and the Nifty.
Currently, the NSE and BSE exchanges calculate an absolute value for the circuit breaker limit using the 10, 15 and 20% price band movement based on the index's quarter-end closing level.
Resumption of trading after a halt triggered by the circuit breaker would now be followed by a 15-minute pre-open call auction session, the Securities and Exchange Board of India (SEBI) said in a circular on Tuesday.
The new rules will come into effect on October 1.
