What kinds of orders are permitted in Periodic Call Auctions?
- Answer Field
-
Limit and market orders alone are allowed in the sessions of a Periodic Call Auction; stop-loss and basket orders are excluded.
BAJAJ BROKING
In this blog, we will discuss periodic call auction and what it means. We will then move on to how it works and its features. We will also talk about the session structure and penalty criteria for periodic call auctions.
Liquidity in stocks is something that affects the way traders approach them. Illiquid stocks - not liquid - are those that have low trading volumes and limited market activity. Basically they are not easily available for trade. In such cases, a periodic call auction comes as a welcome blessing for those who are interested in these stocks. The Securities and Exchange Board of India (SEBI) introduced this option in 2013. This helps in reducing volatility and ensuring that such stocks are discovered at a fair price. Now that we know what is periodic call auction, let’s discuss how it works.
In traditional continuous trading, orders are executed in real-time. In periodic call auctions orders are accumulated over a specific period of time and are executed together as per schedule. This approach makes sure sharp price fluctuations are under control. This is because in cases of illiquid stocks, the lack of constant trading activity can often lead to sharp changes in the price. Now that we have understood how periodic call auctions work, let’s move onto to discuss their features,
Periodic Call Auctions are a highly regulated trading mechanism for illiquid stocks, ensuring fair price discovery and market stability. The system is divided into separate sessions with strict rules of order placement and execution. The following are the key features of Periodic Call Auctions:
1. Illiquidity Criteria
Not all stocks are suitable for Periodic Call Auctions. A stock is classified as illiquid on the basis of the following parameters: if its average daily turnover has reduced below ₹2 lakhs over the last two quarters; if it has been classified illiquid on all the exchanges where it is listed; and if it is not listed in leading indices such as NIFTY 50 or SENSEX, which attract liquidity by virtue of their popularity. The instant a stock is identified to meet these criteria, it is shifted to the Periodic Call Auction system to enable systematic and equitable trade. The exchange periodically searches through the list and updates it. We can call these periodic call auction stocks.
2. Structured Sessions
Periodic Call Auctions divide the trading day into six sessions of one hour each. These sessions prevent illiquid stocks from experiencing high volatility due to uneven order execution.
Trading Hours: The first session opens at 9:30 AM, and each subsequent session goes through a structured cycle until the last session closes at 3:30 PM.
Fixed Intervals: Each session has a predetermined order placement sequence, matching, and execution, and hence, the system is transparent.
Additional Read : Share Market Holiday List 2025
The structured sessions of the system prevent price manipulation risks and eliminate excessive volatility in illiquid stocks.
3. Order Placement and Matching
The trading mechanism in Periodic Call Auctions involves a systematic sequence of order collection and execution:
Order Placement Window (45 minutes): Buy and sell orders are entered within a specified window. The orders are not executed upon entry but saved for processing upon completion of the session.
Price and Volume Discovery: The computer computes the equilibrium price, or the price for which the highest number of shares can be sold.
Order Matching Period (8 minutes): Following the computation of the price, orders are matched according to price and time precedence.
This limited order-matching mechanism avoids discontinuous price shifts that can occur in a continuous trading system.
4. Buffer Period
At the end of each trading session, a buffer period of 7 minutes is added before commencement of the succeeding session. The rationale behind such a pause is to:
Allow the exchange enough time to adjust stock prices accordingly based on traded transactions.
Allow time for analysis of market movement by traders prior to new-order entry.
Prevent incessant order cancellation or revision, which could interfere with price discovery.
This buffer allows smooth session rotation and minimizes order processing lags.
In a call auction, orders are collected within a time interval rather than being executed at the time of order submission. When the interval expires, the accumulated orders are matched to determine one price at which the maximum amount of shares can be traded. This mechanism gives more liquidity and a better picture of the market value of the stock.
Session Structure:
Session Number | Order Placement Time | Order Matching Time | Buffer Period |
1 | 9:30 AM – 10:15 AM | 10:15 AM – 10:23 AM | 10:24 AM – 10:30 AM |
2 | 10:30 AM – 11:15 AM | 11:15 AM – 11:23 AM | 11:24 AM – 11:30 AM |
3 | 11:30 AM – 12:15 PM | 12:15 PM – 12:23 PM | 12:24 PM – 12:30 PM |
4 | 12:30 PM – 1:15 PM | 1:15 PM – 1:23 PM | 1:24 PM – 1:30 PM |
5 | 1:30 PM – 2:15 PM | 2:15 PM – 2:23 PM | 2:24 PM – 2:30 PM |
6 | 2:30 PM – 3:15 PM | 3:15 PM – 3:23 PM | 3:24 PM – 3:30 PM |
The traders place their buy and sell orders within the window of order submission. After the window is over, the system matches the orders to find an equilibrium price at which the maximum number of trades can take place. The buffer interval ensures a smooth movement from one session to the next.
To maintain market integrity, specific penalties are imposed to discourage manipulative practices.
Penalty Conditions: If a client places both buy and sell orders for the same stock at prices that result in self-trades (where the buy price is equal to or higher than the sell price), a penalty is levied.
Penalty Calculations: The penalty for each instance per session is the higher of the following:
0.50% of the trade value for both the buy and sell sides, totaling a 1% penalty.
₹2,500 for the buy trade and ₹2,500 for the sell trade, resulting in a total penalty of ₹5,000.
These measures are designed to prevent self-trading and ensure a fair trading environment.
Periodic Call Auctions are an essential mechanism in enhancing the trading environment for illiquid securities. By organizing the trading sessions and exposing them to stringent regulation, the mechanism achieves fair price discovery, reduces volatility, and upholds the market integrity. Traders who trade illiquid securities benefit through understanding and participating in such auctions because they provide a superior regulated and transparent trading environment.
Do you have a trading account app or demat account app?
You can open an account with Bajaj Broking in minutes.
Download the Bajaj Broking app now from Play Store or App Store.
Disclaimer: Investments in the securities market are subject to market risk, read all related documents carefully before investing.
This content is for educational purposes only. Securities quoted are exemplary and not recommendatory.
For All Disclaimers Click Here: https://www.bajajbroking.in/disclaimer
Share this article:
Limit and market orders alone are allowed in the sessions of a Periodic Call Auction; stop-loss and basket orders are excluded.
Periodic Call Auctions allow orderly trading sessions that result in better balanced price discovery and assist in cutting down volatility in illiquid stocks.
Orders that are not matched at the end of a Periodic Call Auction session are sent back to the trader.
No, trading is restricted to stocks that are identified as illiquid, based on specific parameters, which are the only ones traded through Periodic Call Auctions.
No Result Found
Level up your stock market experience: Download the Bajaj Broking App for effortless investing and trading