The National Stock Exchange recorded ₹1,276.2 crore in turnover during its first day of the new Closing Auction Session. This mechanism replaces the old volume-weighted average price method for stocks with derivative contracts to improve price transparency. ICICI Bank, HDFC Bank, and Reliance Industries saw the highest trading activity during this session.
The National Stock Exchange (NSE) successfully executed its new Closing Auction Session (CAS) on Monday, processing a total turnover of ₹1,276.2 crore. This launch marks a significant change in how the final closing prices of stocks are determined in the Indian equity cash segment. By moving to an auction-based model for shares that have futures and options (F&O) contracts, the exchange aims to move away from the previous volume-weighted average price (VWAP) method.
Market Activity and Top Traded Stocks
During this inaugural session, ICICI Bank emerged as the most actively traded stock, drawing the highest interest from participants. It was followed by major heavyweights including HDFC Bank and Reliance Industries. Other stocks that saw substantial activity during the auction period included Infosys, Bharti Airtel, Bajaj Finance, Tata Consultancy Services (TCS), CG Power, and Axis Bank. Collectively, the top ten most active stocks accounted for roughly 30% of the total turnover recorded during the auction.
Transition to Auction-Based Closing Prices
This change was mandated by the Securities and Exchange Board of India (SEBI) to bring the domestic market in line with international standards. In the previous system, the closing price was calculated based on the average price of trades in the last 30 minutes of the session. The new auction mechanism aggregates buy and sell orders into a single, transparent discovery process. For investors, this shift is intended to prevent sudden, last-minute price volatility and to provide a more representative closing price for the day.
Market Context and Observations
Monday's market session drew attention due to a notable difference in the movement of major indices. The Nifty 50 ended 1.6% higher at 24,774.30, while the BSE Sensex rose 0.7% to 78,639.03. Exchange officials clarified that the indices reflected official prices and confirmed that there were no technical issues, attributing the unique index behavior to the implementation of the new mechanism. In comparison, the Bombay Stock Exchange (BSE) reported a much smaller turnover of ₹10.8 crore for its closing auction, highlighting a sharp contrast in liquidity during these initial implementation hours.
Investors and market participants should monitor how this new mechanism influences price stability in the final minutes of trading over the coming weeks. The primary focus will be on whether the auction process successfully reduces price swings that historically occurred during the previous VWAP-based closing period, especially on days with high market volatility.