SEBI Closing Auction Session: New Stock Market Timings From August 3

India's equity markets are set for a major structural change from August 3, 2026, when the Securities and Exchange Board of India (SEBI) and the National Stock Exchange (NSE) will introduce the Closing Auction Session (CAS) for eligible Futures & Options (F&O) stocks.

The new framework will replace the existing Volume Weighted Average Price (VWAP)-based closing mechanism for F&O stocks with an auction-based system. It will also extend equity derivatives trading by 10 minutes, creating different closing times across market segments, according to SEBI.

Three Different Closing Times

Under the new system, the market will no longer have a single closing time. Non-F&O stocks will continue normal trading till 3:30 pm, with no change. Stocks that are part of the F&O segment will see continuous trading till 3:15 pm, followed by the Closing Auction Session till 3:35 pm. Stock and index F&O trading will run till 3:40 pm, followed by a post-close session between 3:50 pm and 4:00 pm.

This means investors trading in different segments of the market will need to follow different closing schedules going forward.

How The Auction Session Will Work

For F&O stocks, normal trading will end at 3:15 pm instead of continuing till 3:30 pm. These stocks will then move into the Closing Auction Session, where orders are collected and matched to arrive at a single closing price.

The auction process will follow a structured timeline. Between 3:15 pm and 3:20 pm, the market will transition from the Continuous Trading Session to CAS, along with reference price calculation. Market and limit orders can be placed between 3:20 pm and 3:25 pm. From 3:25 pm to 3:30 pm, only limit orders will be allowed, and market orders cannot be modified or cancelled. Random order-entry closure will take place between 3:28 pm and 3:30 pm, followed by order matching and closing price discovery between 3:30 pm and 3:35 pm.

Regular cash market trading will remain unchanged for stocks that are not part of the F&O segment.

Closing Price Calculation To Change

Currently, the closing price is determined using the VWAP of trades executed during the final part of the trading session. Under the new system, all buy and sell orders will instead be pooled together and matched at a single equilibrium price, which will become the official closing price for eligible F&O stocks.

According to SEBI, this approach is expected to improve price discovery by reflecting combined demand and supply from all market participants, rather than relying on prices from trades executed at different times.

The VWAP calculation window used for derivatives will also change. It will now run from 3:10 pm to 3:40 pm, instead of the earlier 30-minute window ending at 3:30 pm.

Extended Window For F&O Traders

The NSE has extended trading hours for equity derivatives from 3:30 pm to 3:40 pm. The additional 10 minutes are intended to align derivatives trading with the new auction-based closing process in the cash market.

The extended session gives derivatives traders more time to hedge open positions, adjust trades after the cash market auction, exit intraday positions, manage expiry-day volatility, and react to auction-based closing prices.

According to SEBI, the new mechanism is aimed at improving the efficiency of closing price discovery. By collecting all buy and sell orders into a single auction pool, the regulator expects the closing price to better represent actual market demand and supply, rather than being influenced by trades executed at different points in the session.