Sebi fixes closing auction CAS 3:30-3:40pm from December 7, 2026
Sebi is shaking up how the stock market wraps up each day.
Starting December 7, 2026, the closing auction session (CAS) will run from 3:30pm to 3:40pm to facilitate transparent and efficient price discovery for closing prices of securities.
CAS gains 3 phases, VWAP settlements
The updated CAS now has three clear phases: one to set a reference price, one for all order types, and a final round just for limit orders.
For expiring index derivatives, settlements will use the volume-weighted average price (VWAP) of constituent securities over the final 30 minutes, and expiring stock derivatives will use the VWAP of the underlying stock over the final 30 minutes.
Stock exchanges and clearing corporations need to update their systems so unexecuted orders get handled more smoothly, all designed to make price discovery fairer and operations less messy.