Since August 3, the National Stock Exchange (NSE) and Bombay Stock Exchange (BSE) have utilized a closing auction session to establish the final settlement price for stocks. This process replaces the previous method of calculating the weighted average price of the final 30 minutes of trade. The auction period begins at 3:28 pm and concludes at a random interval before 3:30 pm, designed to prevent price manipulation and ensure a more representative closing price.

Market participants have noted a divergence in the performance of the Sensex and Nifty indices during this transition. While the auction is intended to provide stability, some traders have expressed concerns regarding how this mechanism affects liquidity and price discovery in the final minutes of the session. Proponents of the rule argue that the random closing time makes it significantly harder for large institutional orders to influence the closing price artificially. Conversely, critics suggest that the lack of predictability in the final price can complicate execution strategies for retail investors who rely on end-of-day orders. As the market adjusts to this new protocol, analysts are monitoring whether the divergence between the two major indices will normalize or if the auction process itself is contributing to increased volatility in specific sectors.