New Market Timings from 3 August 2026: What the Closing Auction Session (CAS) Actually Changes
SEBI's Closing Auction Session went live on 3 August 2026. F&O stocks now stop continuous trading at 3:15 PM, derivatives run until 3:40 PM, and closing prices are set by auction instead of the last-30-minute average. The exact schedule, who is affected, and what it means for intraday and expiry-day traders.
From 3 August 2026, the market no longer closes all at once. F&O-eligible stocks stop continuous trading at 3:15 PM and enter a 20-minute Closing Auction Session; everything else closes at 3:30 PM as before; and index and stock derivatives now trade until 3:40 PM. Closing prices for auction stocks are set by a single equilibrium price, not the last-30-minute weighted average.
The change in four numbers:
Effective
3 Aug 2026
NSE, BSE and MSEI
F&O stocks
3:15 PM
continuous trading ends
Auction window
20 min
3:15 to 3:35 PM
Derivatives
3:40 PM
10 minutes longer
For as long as most retail traders have been active, the Indian market ended the same way every day: trading stopped at 3:30 PM, and the closing price was the volume-weighted average of the last thirty minutes. That is no longer true for a large and important slice of the market.
SEBI's Closing Auction Session went live on 3 August 2026 across NSE, BSE and MSEI. It changes when you can trade, how the closing price is determined, and — most consequentially for anyone in options — it splits the cash and derivatives segments onto different closing bells for the first time.
The new schedule, minute by minute
Trading day from 3 August 2026 (all times IST)
| Time | What happens | Who it applies to |
|---|---|---|
| 9:00 - 9:15 AM | Pre-open session (unchanged) | All stocks |
| 9:15 AM - 3:15 PM | Continuous trading | All segments |
| 3:15 - 3:20 PM | Reference price calculated, ±3% price band set | Category I stocks |
| 3:20 - 3:25 PM | Order entry I — market and limit orders accepted | Category I stocks |
| 3:25 - 3:30 PM | Order entry II — limit orders only, random close | Category I stocks |
| 3:30 - 3:35 PM | Order matching, equilibrium closing price set | Category I stocks |
| 3:30 PM | Normal close, no auction | Category II stocks |
| 3:40 PM | Close of index and stock derivatives | F&O segment |
Market open has not changed. Pre-open still runs 9:00-9:15 AM and continuous trading still begins at 9:15 AM. Everything in this change happens at the other end of the day.
Category I vs Category II — which stocks are affected
- Category I — stocks that have futures and options contracts. These stop continuous trading at 3:15 PM and go into the auction. In this first phase, these are the only stocks in CAS.
- Category II — every other listed stock. Nothing changes: continuous trading until 3:30 PM, closing price calculated the old way.
The practical implication is that two stocks on the same screen can now behave completely differently after 3:15 PM. If you are used to placing cash trades in the last fifteen minutes, that habit only still works on non-F&O names.
How the closing price is now decided
The old method averaged the last thirty minutes of trades, weighted by volume. It was simple and it was gameable — a determined participant could push the close by trading heavily into the window, which matters because closing prices feed index levels, mutual fund NAVs, margin calculations and derivatives settlement.
The auction replaces that. During the order entry windows the exchange collects buy and sell orders without executing them, then finds the single price at which the largest number of shares can trade. Every matched order executes at that one equilibrium price.
The random close between 3:28 and 3:30 PM is the anti-gaming feature. Because nobody knows the exact second order entry freezes, you cannot time a large order to land at the last possible moment and move the print.
What actually changes for you
- Intraday equity traders — square off F&O-eligible positions before 3:15 PM, not 3:30 PM. Fifteen minutes of assumed exit time no longer exists on those names.
- Options traders — you gained ten minutes. Derivatives now run to 3:40 PM, which means you can react to the equity auction outcome before your own segment closes.
- Expiry-day traders — this is the biggest adjustment. The underlying stops trading continuously at 3:15 PM while your option keeps trading to 3:40 PM, so the final twenty-five minutes of an expiry are now priced against an underlying that is in auction rather than moving tick by tick.
- Anyone using closing prices — index closes, NAVs and settlement values for auction stocks now come from the equilibrium price, so a print you saw at 3:29 PM is no longer necessarily the close.
The gap between 3:15 PM and 3:40 PM is genuinely new market structure, not a cosmetic tweak. If your strategy assumes the underlying and its options stop at the same instant, that assumption is now wrong for every F&O name.
Try it now . Free
Watch the auction window live
MarketsEasy now tracks the new session boundaries — live option chain, OI shifts and max pain through the 3:15-3:40 PM window, with an AUCTION status on the ticker so you always know which segment is still trading.
Why SEBI did this
Closing auctions are standard in most large markets — the US, Europe and Japan all use one. The stated goals are better price discovery at the close, lower volatility in the final minutes, and a closing print that is harder to manipulate. Concentrating end-of-day liquidity into one auction rather than spreading it across thirty minutes of continuous trading generally produces a more representative price.
Whether it delivers that in Indian conditions is an empirical question that will take a few months of data to answer. What is certain today is the schedule, and the schedule is what your trading day has to fit around.
- Effective 3 August 2026 on NSE, BSE and MSEI; market open time is unchanged at 9:15 AM.
- F&O-eligible (Category I) stocks stop continuous trading at 3:15 PM and enter a 20-minute closing auction ending at 3:35 PM.
- Non-F&O (Category II) stocks are unaffected and still close at 3:30 PM.
- Index and stock derivatives now trade until 3:40 PM, ten minutes longer than before.
- Closing prices for auction stocks come from a single equilibrium price, with a random close between 3:28 and 3:30 PM to deter manipulation.
Frequently Asked Questions
What time does the Indian stock market close now?
It depends on the segment. F&O-eligible stocks stop continuous trading at 3:15 PM and finish their closing auction at 3:35 PM. Non-F&O stocks close at 3:30 PM as before. Index and stock derivatives now close at 3:40 PM. Market open is unchanged at 9:15 AM.
What is the Closing Auction Session (CAS)?
CAS is a 20-minute window from 3:15 PM to 3:35 PM in which the exchange collects buy and sell orders for F&O-eligible stocks without executing them, then matches them all at a single equilibrium price — the price at which the maximum number of shares can trade. That price becomes the official close, replacing the earlier volume-weighted average of the last 30 minutes.
Which stocks are part of CAS?
In the first phase, only Category I stocks — those with active futures and options contracts. All other listed stocks are Category II and continue to trade until 3:30 PM with the previous closing-price method.
Can I still trade between 3:15 PM and 3:40 PM?
Yes, but not everything. For F&O-eligible stocks you can place, modify and cancel auction orders during the order entry windows rather than trading continuously. Non-F&O stocks trade normally until 3:30 PM. Derivatives trade continuously until 3:40 PM.
Why is there a random close between 3:28 and 3:30 PM?
To prevent manipulation. If order entry always froze at a known instant, a large participant could time an order to land at the last possible moment and shift the closing price. Because the freeze happens at a system-determined random second within that two-minute window, that tactic no longer works.
Does CAS change expiry-day trading?
Yes, materially. The underlying stock stops continuous trading at 3:15 PM while its options continue until 3:40 PM, so the last twenty-five minutes of an expiry are now priced against an underlying that is in auction rather than trading tick by tick. Any strategy that assumed both closed simultaneously needs revisiting.
MarketsEasy Research
Market Research
Derivatives and market-structure desk at MarketsEasy, writing from live NSE data.