The proposed CAS will involve a 15-minute session held after regular trading hours, from 3:30 PM to 3:45 PM. This session will be divided into four stages: reference price determination, order input, a no-cancellation period with a random closing of orders and final trade confirmation and order matching. During this period, investors can place buy and sell orders to establish the closing price of a stock.

Currently, the closing price of a stock in India is determined using the Volume Weighted Average Price (VWAP) of the last 30 minutes of trading. SEBI argues that this system does not always reflect true market conditions, particularly during high volatility or significant market events.

Fund managers and investors have raised concerns that the current method could lead to price distortions, especially on days involving index rebalancing or derivatives expiry. Passive fund houses have also pointed out risks such as increased price volatility and unfulfilled large orders under the VWAP system.

SEBI proposes a phased introduction of the CAS, starting with stocks that have derivative products, ensuring sufficient liquidity. The system may later be expanded to include other stocks as it proves effective.

Closing prices are critical in financial markets as they serve as a reference for the next day’s trading, portfolio valuations, and stock analysis by fund managers and analysts. SEBI’s proposed CAS aims to improve accuracy and minimize misleading signals for investors by providing more transparent and robust price discovery mechanisms.

SEBI has invited public suggestions on the CAS proposal, with a submission deadline of December 26, 2024. The feedback will be instrumental in refining the design and ensuring the system effectively addresses market participants' needs.

This reform marks another step by SEBI toward enhancing transparency and efficiency in India's equity markets, aligning them with global best practices.