Market Related
What is Periodic Call Auction (PCA), and how does it work?
When a stock is under Periodic Call Auction (PCA), it means the stock is classified as illiquid by the exchange due to its low trading volume and limited investor interest. Instead of real-time continuous trading, these stocks are traded through scheduled auction sessions. This mechanism is designed by SEBI to curb price manipulation, enable better price discovery, and protect investor interests.
How it Works:
In a PCA (Periodic Call Auction), buy and sell orders are gathered over a set period of time and matched all at once at the same price. This batch process helps keep prices stable and reduces big price swings.
PCA Trading Timings & Slots:
- PCA sessions are conducted every hour during market hours (9:30 AM to 3:30 PM).
- Each session is 60 minutes long and consists of:
- Order Entry Period – 45 minutes
- Order Matching & Trade Confirmation – 8 minutes
- Buffer Period – 7 minutes (used for closing the session and preparing for the next)
Session No. Start Time- Order Placement Order matching Buffer period
1 09:30 AM - 10:15 AM 10:15 AM - 10:23 AM 10:24 AM to 10:30 AM
2 10:30 AM - 11:15 AM 11:15 AM - 11:23 AM 11:24 AM to 11:30 AM
3 11:30 AM - 12:15 PM 12:15 PM - 12:23 PM 12:24 PM to 12:30 PM
4 12:30 PM - 01:15 PM 01:15 PM - 1:23 PM 01:24 PM to 01:30 PM
5 01:30 PM - 02:15 PM 02:15 PM - 2:23 PM 02:24 PM to 02:30 PM
6 02:30 PM - 03:15 PM 03:15 PM - 3:23 PM 03:24 PM to 03:30 PM
What You Can Do:
- You can place limit orders only on PCA stocks. Market orders are disabled.
- Orders will be executed only during the matching window of the next PCA slot.
- If no match is found in that slot, the order stays pending or may expire at end of day (if not modified or cancelled).
- You’ll see a clear notification or message on ICICI Direct if a stock falls under PCA before you place the order.
Key Points to Remember:
- PCA is applicable only to stocks marked illiquid by the exchange (NSE/BSE).
- Trading in PCA stocks involves delayed execution, limited liquidity, and potentially wider price spreads.
- Stocks can move in and out of PCA based on their liquidity profile as reviewed by the exchanges periodically.