Published on: 2026-08-03
Updated on: 2026-08-03
At 3:15 p.m., continuous cash trading ends for eligible shares before the official closing price exists. A 20-minute auction then takes over while futures and options continue until 3:40 p.m. Orders, intraday exits and how the closing price is reached now follow different rules during the final 25 minutes of India’s trading day.
CAS initially covers cash shares with listed derivatives, so the affected universe must be checked separately from shares that continue trading normally until 3:30 p.m.
No new cash orders are accepted from 3:15 to 3:20, leaving only a five-minute window from 3:20 to 3:25 for fresh market orders.
The final trade before 3:15 does not determine the close; the exchange selects the price that executes the greatest quantity within a ±3% band.
Broker square-off policies can close an intraday position before CAS begins, even while an eligible limit order remains in the exchange book.
F&O remains open until 3:40, creating a five-minute window to adjust hedges after the cash close is confirmed.
The previous system calculated the official close from trades completed during the final 30 minutes. Large end-of-day orders still had to enter a continuously moving market, making their execution price dependent on when they reached the VWAP window.
CAS places closing demand and supply into one match. The structure gives large index-rebalancing and portfolio-adjustment orders a single executable closing price rather than forcing them through several prices during the final half-hour.
SEBI’s consultation data put passive equity assets held through foreign portfolios at about ₹20.5 lakh crore and domestic mutual fund passive assets at ₹9.18 lakh crore in July 2025. Even a narrow gap between execution prices and the official close can create material tracking error across portfolios of that scale.
The first sessions will be judged through auction volume, unmatched order imbalances and the gap between cash and futures prices. Strong participation near the reference price would support the new mechanism. Repeated price gaps or one-sided order books would expose weak closing liquidity.
Continuous cash trading ends at 3:15 p.m. only for shares with listed futures or options. Shares outside CAS continue trading until 3:30 p.m. and retain the existing closing-price method.
Order access changes twice before the final match.
| Time | Cash-market phase | What happens |
|---|---|---|
| 3:15–3:20 | Reference-price period | No new cash orders |
| 3:20–3:25 | Initial order entry | Market and limit orders accepted |
| 3:25–3:28/3:30 | Limit-order period | Only limit orders accepted |
| 3:30–3:35 | Final matching | Orders matched at one closing price |
Order entry closes at a random point between 3:28 and 3:30. Randomisation reduces the opportunity to place or withdraw a large order at a predictable final second.
Unexecuted limit orders can carry into CAS when their prices remain within the auction band. They keep priority over new limit orders submitted during the auction.
Changing the price removes the order’s original time priority and triggers another margin check.
Four categories are excluded.
Stop-loss orders do not carry forward.
Iceberg and disclosed-quantity orders do not carry forward.
Immediate-or-cancel orders are unavailable.
Orders outside the auction band are rejected.
After 3:25, a market order already in the book cannot be changed or cancelled. Any quantity left unmatched is cancelled by the exchange when the auction ends.
The final trade before 3:15 does not set the official close. The exchange selects the price that allows the largest quantity of shares to trade.
The reference price comes from the stock’s volume-weighted average price between 3:00 and 3:15. If no trade occurs during that window, the latest trade from the day is used. A stock that has not traded all day falls back to its previous close, adjusted for any corporate action.
All auction orders must remain within a ±3% band around that reference price.
The example below shows how the maximum-volume rule works.
| Price | Buy quantity | Sell quantity | Shares matched |
|---|---|---|---|
| ₹99 | 10,000 | 4,000 | 4,000 |
| ₹100 | 8,000 | 7,000 | 7,000 |
| ₹101 | 5,000 | 9,000 | 5,000 |
₹100 becomes the official close because 7,000 shares can trade there, more than at either alternative price.
If several prices match the same maximum quantity, the exchange chooses the one with the smallest unmatched quantity. A remaining tie goes to the price closest to the reference price.
Once the closing price is selected, market orders execute before eligible limit orders. If no matching price forms, the reference price becomes the official close.
An intraday position can be closed before 3:15 because the broker, not the exchange, sets the automatic square-off time.
Broker cutoffs vary. Zerodha, for example, schedules automatic MIS square-off for CAS shares at 3:10 p.m., five minutes before continuous cash trading ends.
Pending orders follow separate exchange rules. An eligible limit order can remain in the order book and carry into CAS even after a broker-controlled intraday position has been closed.
The applicable deadline depends on the product used and the broker’s risk policy, not only on the exchange timetable.
Futures and options remain open until 3:40 so positions can respond to the cash auction and be adjusted after the closing price is known.
Derivatives do not participate in CAS. They continue trading normally while the cash market collects and matches auction orders. The cash close is scheduled to be established by 3:35, leaving five minutes to adjust a hedge against the confirmed price.
Stock futures receive a separate reference price based on futures trades between 3:00 and 3:15. A static ±3% operating range then applies through 3:40, while options retain their existing price-control methodology.
Cash and futures reference prices can differ because they come from separate order books.
Yes. A post-close session runs from 3:50 to 4:00 p.m. Orders can execute only at the official closing price and require matching interest. Continuous price discovery does not restart.
Yes. Each exchange calculates its own reference price and runs a separate auction. Different orders and liquidity on each venue can produce different closing prices for the same share.
The daily F&O closing-price method remains unchanged and uses the final 30-minute VWAP from 3:10 to 3:40. Exchanges provide those closing prices to clearing corporations for settlement-price calculations.
No. CAS is not conducted when a market-wide circuit breaker ends trading before the scheduled close. The applicable 30-minute VWAP or last-traded-price method is used instead.
The safeguards reduce several last-second tactics but cannot make manipulation impossible. Randomised closure, a ±3% band and visible imbalance data limit timing and price-range risks, while thin liquidity or one-sided orders can still influence the final match.
The four deadlines at 3:15, 3:25, 3:35 and 3:40 now carry different consequences. Treating them as one closing bell risks missed orders, early square-offs and incomplete hedges. The final minutes will reward precise timing more than familiar end-of-day habits.
