NSE CAS turnover surges to ₹63,000 crore in first month
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The National Stock Exchange’s (NSE) newly introduced Closing Auction Session (CAS) recorded cumulative turnover of ₹63,000 crore in its first month, indicating strong adoption of the new mechanism among market participants.
The exchange recorded the highest activity on August 31, when CAS turnover touched ₹39,718 crore, or around $4.2 billion, as the market witnessed its first index rebalancing since the mechanism went live, NSE said in a release.
The Monday’s session accounted for 22% of NSE’s total cash-market turnover, with more than 98,000 unique investors participating. CAS commanded a 99.9% market share, while its turnover was nearly 42 times that recorded in the previous trading session.
“CAS accounted for 22% of the day's total cash market turnover on NSE, and more than 98,000 unique investors participated in today's session. Today's CAS turnover was approximately 42 times the turnover recorded in the previous trading session,” the country’s largest exchange said.
MSCI rejig drives ₹39,718 crore CAS turnover
The historic ₹39,718 crore turnover in its CAS on Monday was driven by the MSCI August 2026 Index Review, which took effect at the close of trading on August 31.
Index-rebalancing days typically see heavy trading towards the close as index funds, exchange-traded funds and other passive investors realign their portfolios at closing prices.
The sharp rise in activity on the rebalancing day offered an early test of the CAS framework, particularly among index funds and passive investors that need to execute large trades at the closing price.
CAS is a call-auction mechanism used to determine the closing price of stocks in the cash segment on which derivative contracts are available. It aggregates buy and sell interest at the close into a single price-discovery process.
Sebi introduced CAS on August 3 as part of efforts to prevent market manipulation and increase transparency. Under the framework, buy and sell orders are pooled without immediate execution during a designated window toward the end of trading, with orders matched through an auction-style process.
NSE said the mechanism is designed to improve transparency, integrity and fairness in closing-price discovery and align the Indian market with global best practices.
“The successful completion of the first month of the Closing Auction Session marks an important milestone for the Indian capital markets, and the confidence shown by the market on the first index rebalancing day after CAS went live is a strong endorsement of the mechanism,” said Sriram Krishnan, chief business development officer at NSE.
“We sincerely thank all market participants for their trust and support. We are especially grateful to index funds and passive investors, who placed their trust in NSE and in the Closing Auction Session on a day of such significance,” he added.
Krishnan also thanked the Securities and Exchange Board of India (Sebi) for its guidance and support in introducing the closing auction framework.
The exchange said the growth in CAS turnover during its first month reflects increasing acceptance of the mechanism among institutional investors, brokers and retail participants.