Market regulator SEBI on Thursday issued final framework on Closing Auction Session (CAS). SEBI has retained the 30-minute volume-weighted average price (VWAP) methodology for determining expiry-day settlement prices of index and stock derivatives, while revising the timings and operational framework of the CAS in the equity.

Under the revised framework, the CAS will operate from 3:30 pm to 3:40 pm on all trading days. The changes will take effect from December 7, 2026, except for provisions governing the transition of unexecuted limit and iceberg orders from the continuous trading session, which will come into effect on February 8, 2027. The current period of CAS is from 3:15 PM to 03:35 PM.

As per the circular trading in index derivatives will continue until 3:45 pm on normal trading days, but expiring index derivatives contracts will stop trading at 3:30 pm on expiry days. Stock derivatives will trade until 3:45 pm, including on expiry days.

Source:- https://www.sebi.gov.in/sebi_data/attachdocs/oct-2026/1792079571420.pdf