The exchange commanded a 99.9% market share in the CAS, with more than 98,000 unique investors participating in the session, NSE said in a statement.
The turnover in Monday’s session was around 42 times the turnover recorded in the previous trading session.
The session coincided with the implementation of the MSCI August 2026 Index Review, which took effect at the close of trading on Monday. It was the first major index rebalancing after CAS went live in the Indian capital markets.
Index rebalancing days typically witness heavy trading towards the close as index funds, exchange-traded funds and other passive investors realign their portfolios based on changes in benchmark indices.
NSE said the strong turnover in the CAS demonstrated that index funds and passive investors executed their rebalancing trades through the mechanism.
Monday also marked the completion of one month of the closing auction session. During the first month, NSE recorded a cumulative CAS turnover of around ₹63,000 crore, with a market share of 98.2%.
The CAS is a call auction mechanism used to determine the closing price of stocks in the cash segment on which derivative contracts are available.
Under the mechanism, buy and sell interest at the close of the market is aggregated into a single price discovery process, aimed at enhancing transparency, integrity and fairness in determining closing prices.
The mechanism was implemented from August 3 following the Securities and Exchange Board of India’s (Sebi) decision to introduce the closing auction session in the Indian capital markets.
NSE said the CAS brings the Indian market closer to global best practices for closing price discovery.
