SEBI Announces New CAS Timings and Order Types Effective December 7, 2026
The Securities and Exchange Board of India updates the closing auction session framework, introducing new timings and order types.
Closing auction session will run from 3:30 p.m. to 3:40 p.m.
Reference prices will be based on volume-weighted average prices during the last 15 minutes of trading.
Only limit and market orders will be allowed during the closing auction.
The Securities and Exchange Board of India (SEBI) has unveiled significant changes to the closing auction session (CAS), which will take effect on December 7, 2026. The auction window is now set from 3:30 p.m. to 3:40 p.m., and the reference price for eligible securities will be calculated based on the volume-weighted average price (VWAP) of trades executed in the final 15 minutes of continuous trading in the cash market.
Under the revised framework, the order-entry period will conclude at a randomly determined time between 3:38 p.m. and 3:40 p.m., with the closure being system-driven. Following the end of order entry, stock exchanges will match orders and promptly disseminate the closing price and executed quantities. This change aims to enhance the efficiency and transparency of the auction process.
Additionally, SEBI has established distinct trading cut-off times for index and stock derivatives. Index derivatives will continue trading until 3:45 p.m. on regular days, but contracts nearing expiration will cease trading at 3:30 p.m. on expiry days. Stock derivatives will maintain the same trading hours across all days, including expiry days, ensuring consistency in market operations.
The post-close session in the cash market will operate from 3:50 p.m. to 4:00 p.m., where trades will be executed at the closing price of the respective securities. For special trading sessions, the closing price will also be determined through CAS, with the auction lasting 10 minutes and the derivatives segment closing five minutes after the auction.
The new rules dictate that the reference price for a security will be determined using its VWAP during the last 15 minutes of trading. If no trades occur during this period, the last traded price of the day will be used. In cases of corporate actions, the previous day's adjustable closing price will serve as the reference. Furthermore, only limit and market orders will be allowed during the CAS, with restrictions on iceberg and stop-loss orders, ensuring full transparency in order disclosures.
