Stock Market Timings Change From 3 August 2026: New CAS Timings Explained

The Indian stock market has introduced one of its biggest structural changes in recent years. Effective 3 August 2026, the Securities and Exchange Board of India (SEBI) has implemented the Closing Auction Session (CAS) for selected stocks. Along with this change, trading hours for Equity Futures & Options (F&O) have been extended by ten minutes.

These changes are intended to improve price discovery, reduce market manipulation near the market close, and provide a more transparent mechanism for determining the official closing price of major stocks. Whether you are a long-term investor, delivery trader, intraday trader, or derivatives trader, understanding these new market timings is essential.

New Stock Market Timings (Effective 3 August 2026)

Market Segment	Previous Timing	New Timing	Status
Cash Market (F&O Eligible Stocks)	9:15 AM – 3:30 PM	9:15 AM – 3:15 PM	Changed
Closing Auction Session (CAS)	Not Available	3:15 PM – 3:35 PM	New
Cash Market (Non-F&O Stocks)	9:15 AM – 3:30 PM	9:15 AM – 3:30 PM	No Change
Equity Futures	9:15 AM – 3:30 PM	9:15 AM – 3:40 PM	Extended by 10 Minutes
Equity Options	9:15 AM – 3:30 PM	9:15 AM – 3:40 PM	Extended by 10 Minutes
Index Futures	9:15 AM – 3:30 PM	9:15 AM – 3:40 PM	Extended by 10 Minutes
Index Options	9:15 AM – 3:30 PM	9:15 AM – 3:40 PM	Extended by 10 Minutes
Commodity Futures & Options	No Change	No Change	Unchanged
Post-Close Session	3:40 PM – 4:00 PM	3:50 PM – 4:00 PM	Revised

Closing Auction Session (CAS) Timeline

Time	Activity
3:15 PM – 3:20 PM	Reference Price Calculation
3:20 PM – 3:25 PM	Market & Limit Order Entry
3:25 PM – 3:30 PM	Limit Order Entry Only
3:30 PM – 3:35 PM	Order Matching & Final Closing Price Determination

Why Did SEBI Introduce Closing Auction Session (CAS)?

The closing price of a stock plays a crucial role in India's financial markets. It is used for settlement of derivatives, valuation of investment products, and calculation of benchmark indices. Earlier, the closing price was calculated using the Volume Weighted Average Price (VWAP) during the final 30 minutes of regular trading.

Large trades executed in the last few minutes could sometimes influence the official closing price. To make closing prices more transparent and resistant to manipulation, SEBI introduced the Closing Auction Session.

The closing price is used for:

Settlement of Futures & Options contracts
Calculation of NSE and BSE indices
Mutual Fund Net Asset Value (NAV)
ETF valuation
Portfolio valuation
Passive fund tracking

Objectives of CAS

Improve transparency
Reduce price manipulation
Ensure fair closing prices
Improve market efficiency
Strengthen investor confidence

What Is Closing Auction Session (CAS)?

The Closing Auction Session (CAS) is a dedicated trading session conducted after continuous market trading ends for eligible stocks.

Instead of executing orders instantly, the stock exchanges collect eligible buy and sell orders during the auction window. Once the order collection period ends, the exchange determines a single equilibrium price at which the maximum number of shares can be matched.

This equilibrium price becomes the official closing price of the stock and is used for settlement and valuation purposes.

Which Stocks Are Covered?

Initially, the Closing Auction Session applies only to selected Futures & Options (F&O) eligible stocks.

Stocks listed in the Futures & Options segment.
Stocks available on both NSE and BSE.

Stocks that are not covered under CAS will continue trading until 3:30 PM, and their closing price will continue to be calculated using the existing VWAP-based method.