From December 7 NSE shortens CAS and extends derivatives trading
Starting December 7, 2026, the NSE is making some changes: the Closing Auction Session (CAS) for stocks will now be just 10 minutes, happening from 3:30pm to 3:40pm.
Plus, if you're into equity derivatives, you'll get a little more time. Trading will go on until 3:45pm for stock derivatives, and index derivatives will also trade until 3:45pm on regular days, but contracts expiring that day stop at 3:30pm on expiry days.
NSE tweaks expiry day settlements
This update follows SEBI's recent review of market timings and how derivative settlements work.
The new CAS will have set slots for entering orders and figuring out prices, now based on the average price before the session starts.
NSE is also tweaking how expiry-day prices are settled for derivatives and plans to run mock trading sessions so everyone can get used to the new system.
More details are in official updates from the NSE.