Dear Client,
Please note that, effective 3 August 2026, the Closing Auction Session (CAS) will be introduced for eligible F&O stocks as per the latest exchange framework.
As part of this change, the market closing process and auto square-off timings for certain order types have been revised.
Revised Market & Auto Square-Off Timings
What is the Closing Auction Session (CAS)?
The Closing Auction Session (CAS) is a dedicated auction conducted after continuous trading for eligible F&O stocks to determine the official closing price.
During this session, buy and sell orders are matched by the exchange, and a single closing price is discovered based on the highest executable trading volume. This replaces the earlier methodology of deriving the closing price from the last 30 minutes’ VWAP for eligible stocks.
Closing Auction Session Timeline
Order entry will close at a random time between 3:28 PM and 3:30 PM to discourage last-minute order placement.
Why is the Closing Price Important?
The official closing price is used for:
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Index calculations (Nifty & Sensex)
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F&O settlement prices
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Mutual Fund & ETF NAV calculations
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Portfolio valuation
Applicable To
This communication is intended for clients trading eligible F&O stocks using MIS (Margin Intraday Square-off), BO (Bracket Order), or CO (Cover Order) product types.
Please take note of the revised market and auto square-off timings effective 3 August 2026 and plan your trades accordingly.