What is the Closing Auction Session (CAS)?

The Closing Auction Session (CAS) is a dedicated session conducted by the exchange right after regular trading ends. During this session, the exchange collects and matches eligible buy and sell orders to discover a single, unified closing price for the day.

Note: Starting August 3, 2026, the CAS will replace the traditional method of calculating the closing price for equity shares that have Futures & Options (F&O) contracts.

Previously, the closing price was calculated using the Volume Weighted Average Price (VWAP) of all trades executed in the last 30 minutes of regular trading.