From 03 August 2026, SEBI introduce the Closing Auction Session (CAS) to determine the official closing price of eligible equity stocks. Instead of relying only on the Volume Weighted Average Price (VWAP), the exchange will conduct an auction at the end of the trading day.

Initially, CAS will apply only to cash-market equity stocks that have derivative contracts.

Closing Auction Session timings

How is the closing price determined during CAS

Orders during CAS can be placed within a fixed price band of ±3% from the reference price.

• The VWAP calculated between 3:00 PM and 3:15 PM becomes the reference price.
• The exchange identifies the price at which the maximum quantity of buy and sell orders can be matched.
• This equilibrium price becomes the official closing price of the stock.
• If no equilibrium price is discovered, the applicable reference price will be used as the official closing price.

Which order types are allowed during CAS

The following order types are supported during CAS:

• Limit orders
• Market orders

The following order types are not allowed during CAS:

• Stop-loss orders
• Disclosed Quantity orders
• Iceberg orders

Market orders receive priority over limit orders during the matching process.

Eligible unexecuted limit orders from the continuous trading session will automatically move to CAS.

Which stocks are covered under CAS

CAS initially applies only to cash-market equity stocks that have derivative contracts.

For other securities, the closing price will continue to be calculated using the existing VWAP-based method.

How does CAS affect stock futures

From 3:15 PM to 3:40 PM, stock futures will trade within a fixed ±3% price band. The reference price for this band will be calculated separately for each futures contract.

How does CAS affect FYERS Smart Orders and Smart SIPs

For CAS-enabled symbols, Smart Order and Daily Smart SIP timings must be set before 3:15 PM. Smart Orders cannot be created during the Closing Auction Session.

What if...