What are the new SEBI closing auction session timings?

The session will run for 10 minutes, from 3:30 pm to 3:40 pm, on trading days. It has a 1-minute reference-price stage, a 5-minute stage for market and limit orders from 3:31 pm, and a 4-minute limit-only stage from 3:36 pm.

When do the revised closing auction rules take effect?

Most changes take effect from December 7, 2026. Rules governing the transition of unexecuted limit and iceberg orders into the closing auction come into force from February 8, 2027.

Until what time can derivatives trade under the revised framework?

Index derivatives trade until 3:45 pm on regular days and stop at 3:30 pm on expiry days. Stock derivatives trade until 3:45 pm on all days, including expiry days.

What happens to unexecuted limit and iceberg orders at the close of continuous trading?

Unexecuted limit orders generally carry into the auction, except stop-loss orders and orders outside the auction price bands. Iceberg orders within the bands convert to fully disclosed limit orders unless the participant opted out, and they rank below other carried-over limit orders.

How is the reference price set for the closing auction?

It is the VWAP of trades in the last 15 minutes of continuous trading. If there were no trades in that period the last traded price is used, and if the security did not trade that day the previous close is used, adjusted for corporate actions.

SEBI Revises Closing Auction Session to 3:30-3:40 pm; Derivatives Rules From Dec 7

Q: How will derivatives expiry settlement prices be calculated?

Index derivatives will settle on the index value computed from the VWAP of constituent stocks over the last 30 minutes of continuous trading. Stock derivatives will use the VWAP of the underlying stock over the same 30 minutes across all stock exchanges.

The SEBI closing auction session will run for 10 minutes, from 3:30 pm to 3:40 pm, under a revised framework that also changes how settlement prices are set for stock and index derivatives. Most changes take effect from December 7, 2026, and the rules for unexecuted limit and iceberg orders apply from February 8, 2027. This is an announced regulatory framework. Nothing in it is in force today.

What changes in the SEBI closing auction session

The closing auction session (CAS) has been used in the equity cash market since August 3, 2026, under SEBI's January 16, 2026 framework. The revision follows a consultation paper issued on September 12, 2026, which sought public comments on auction functioning, market timings and derivatives settlement methodology.

Item	Previous (Jan 2026 framework)	Revised	Change
Auction window	3:15-3:35 pm (20 minutes)	3:30-3:40 pm (10 minutes)	Half the length, starts 15 minutes later
Derivatives trading ends	3:40 pm	3:45 pm (index derivatives on expiry day: 3:30 pm)	5 minutes later; earlier cut-off for index expiry
Post-close cash session	3:50-4:00 pm	3:50-4:00 pm	Unchanged
Expiry settlement basis	Auction-determined closing prices	30-minute VWAP of continuous trading	Methodology change

How the 10-minute session is structured

The session has three stages. In the first minute, from 3:30 pm, the exchange calculates a reference price and moves orders across from continuous trading. From 3:31 pm, market and limit orders can be entered for five minutes. From 3:36 pm, only limit orders are allowed for four minutes. Order entry closes at a system-driven random time between 3:38 pm and 3:40 pm, after which exchanges match orders and publish the closing price and traded quantity as soon as practicable.

The reference price is the VWAP of trades in the last 15 minutes of continuous trading. If nothing traded in that period, the day's last traded price is used. If the security did not trade that day, the previous close is used, adjusted for any corporate action.

Derivatives timings and expiry settlement

Index and stock derivatives continue to trade until 3:45 pm on regular days, 15 minutes after continuous cash trading ends at 3:30 pm. On expiry days, expiring index contracts stop at 3:30 pm, before the auction begins. Stock derivatives keep trading until 3:45 pm, including on expiry days.

For settlement, index derivatives will use the value of the underlying index computed from the VWAP of constituent stocks over the last 30 minutes of continuous trading. Stock derivatives will use the VWAP of the underlying stock over the same 30 minutes across all exchanges. Exchanges will pass the VWAP and traded quantity to clearing corporations and publish indicative values in real time.

Rules for unexecuted orders

Unexecuted limit orders at the end of continuous trading will generally be carried into the auction, except stop-loss orders and orders priced outside the auction price bands. Unexecuted iceberg orders within the bands become fully disclosed limit orders, unless the participant opted out when placing the order. An iceberg order splits a large order into smaller visible slices.

Converted iceberg orders rank below other limit orders carried over from continuous trading. Carried-over orders rank above limit orders placed during the auction, and modifying a carried-over order changes its time priority. Only market and limit orders can be placed during the auction, and new iceberg and stop-loss orders are not allowed. Orders placed in the auction face order-level margin requirements. Eligible carried-over orders attract margin only if modified.

What to Watch

Within seven days of the circular, exchanges and clearing corporations must amend their operating procedures in consultation with SEBI.
December 7, 2026: most revised timings and settlement rules take effect.
February 8, 2027: rules for transitioning unexecuted limit and iceberg orders into the auction take effect.