Context:
The Securities and Exchange Board of India (SEBI) has proposed introducing a Closing Auction Session (CAS) initially for stocks deriving from derivatives to streamline and stabilize how closing prices are determined in the stock market.
Closing Auction Session (CAS)
The Closing Auction Session (CAS) is a process used by stock exchanges to decide the final price of a share at the end of the trading day. It ensures fair price discovery by consolidating buy and sell orders into a single closing price.
Key Features:
- Purpose:
- To arrive at a single closing price for securities.
- Reduce volatility and manipulation during market close.
- How it Works:
- Participants can place buy or sell orders during the CAS period.
- The exchange matches orders at a single equilibrium price where the maximum volume can be traded.
- Any unmatched orders are carried forward to the next trading day (subject to exchange rules).
- Timing:
- Typically occurs in the last few minutes of the trading session.
- Duration may vary by exchange (e.g., NSE CAS runs from 3:30 PM to 3:40 PM for most securities).
- Importance:
- Provides transparent and fair price discovery.
- Reflects the true market value of a security at the close of the trading day.
- Used for portfolio valuations, index calculation, and mutual fund NAVs.
- Exchanges Implementing CAS:
- NSE (National Stock Exchange of India)
- BSE (Bombay Stock Exchange)
