Pre-Open Session FAQs
What is Pre-Open Session?
  Pre-Open Session is a new innovation on exchange side to arrive at the ideal opening price of a scrip for the current trading session. The session intends to reduce the volatility that accompanies during the beginning of the day. Under this new arrangement, the exchange will collect the orders for the first few minutes of this session. On the basis of orders received, the exchange arrives at Opening Price and trades matchable orders on that price. Remaining orders are moved to normal trading session.
What are the timings for Pre-Open Session?
  The duration of Pre-Opening Session will be of 15 minutes – from 9:00 A.M. to 9:15 A.M. The session will have three phases–
Order Entry Period
9:00am - 9:07/08am
The client can place new orders, modify / delete the orders. The order entry can stop randomly between 7th and 8th minute.
Order Matching & Confirmation Period (can be called Price Discovery Period)
9:08am - 9.12am
The exchange arrives at the Opening Price, trades the matchable orders @ Opening Price.
The client cannot modify or delete the orders during this period.
Buffer Period
9:12am - 9:15am
Used as transition period between pre open and continuous trading sessionBottom of Form
Normal Market
9:15 A.M – 3:30 P.M.
Normal Trading resumes.
What happens to orders that are not matched / traded during Pre-Open session?
The orders that have not been traded are carried forwarded to the normal trading session.
  1. Limit Orders that are not traded during Pre-Open Session will be moved to normal trading session at the same price.
  2. Market Orders that are not traded during Pre-Open session will be moved to normal trading session @ Opening Price.
  3. If Opening Price is not discovered during Pre-Open session, then the market orders will be shifted to Normal trading session @ Previous Day Closing Price.
How the exchange arrives at the Opening Price?
Let’s suppose, we have the following Order Book on a scrip:
Buy Quantity
Buy Price
Sell Price
Sell Quantity
100 Market 91 100
100 96 91.5 100
150 95 93 100
50 93 95 100
100 91.5 96 200
100 91    
The system will now calculate the cumulative tradable quantity @ each price
Price Point
Cumulative Buy Quantity
Cumulative Sell Quantity
Tradable Quantity
96.0 200 600 200
95.00 350 400 350
93.00 400 300 300
91.50 500 200 200
91.00 600 100 100
100 91    
The maximum Tradable Quantity is @ 95 Rs. So, the system will mark 95 Rs as Opening Price and execute the tradable quantity @ that price. The remaining orders will be moved to the normal market session according to the logic discussed above.
Can I place orders in all scrips during Pre-Open Session?
You can only place orders in scrips that form the Nifty & Sensex indices. Though this list is subject to change and will be notified by exchanges accordingly. You can regularly visit "Pre-Open scrips" link given on the Trading Website to view the list of scrips in which Pre-Open Trading session is allowed.
Can I also place orders in F&O contracts of these scrips during Pre-Open Session?
No. Currently, Pre-Open session is not available in F&O segment.
Can I place orders in Intraday / Margin Trading products during Pre-open Session?
Yes. You can place order in any product (Cash / Intraday / Margin) during Pre-Open Session.
When will I know whether my orders have been executed or not?
Orders are traded in the IInd phase – “Order Matching and Confirmation Phase” of Pre-Open Session. You will receive trade confirmations during that phase only i.e., tentatively between 9:08-9:12 A.M.
Is there any restriction on specific order types during Pre-Open Session?
Yes. Exchanges stipulate that only Limit and Market Orders will be allowed during Pre-Open Session.
Order Type Exchange Allowed / Disallowed
Limit NSE Allowed
BSE Allowed
Market NSE Allowed
BSE Allowed
Day NSE Allowed
BSE Allowed
Market Protection% NSE Not Applicable
BSE Allowed
Stop Loss / Trigger Price NSE Disallowed
BSE Disallowed
IOC NSE Disallowed
BSE Disallowed
Disclosed Quantity NSE Disallowed
BSE Disallowed
Can I place Offline Orders during Pre-Open Session?
No. You cannot place fresh offline orders / modify existing offline orders during Pre-Open Session. Though you can delete the existing offline orders placed by you.
How to interpret the Order Book of NSE and BSE?
For Pre-Open Session, the Order Book of scrips in NSE and BSE need to be interpreted differently.
  1. NSE Order Book will have four Limit Order legs and one Market Order legs on both Bid and Offer side. The last leg of the Order Book on either side will be for Market orders. All the market orders placed by you will come under this leg.
  2. Each Limit Order leg will show the exact price and quantity available on that price. For Market Order leg, Order Book will display Price as “0” and Quantity as total quantity of the market orders on that side.
  1. BSE Order Book will have all limit order legs and each leg will display the cumulative tradable quantity at that leg.
  2. Market Orders will not be treated separately in the Order Book.
Is there any Price Limit on the orders placed by you during Pre-Open Session?
You cannot place order beyond +/- 20% of Previous Day Closing Price. For ex. If the closing price of scrip is Rs. 100, you cannot place an order beyond 80-120 Rs price range during Pre-Open Session.
Can I view the Tentative Opening Price during Pre-Open Session?
You may view the Tentative Opening Price for a scrip in "LTP" field during Pre-Open Session. This will be updated after every few seconds according to the orders placed in that scrip.
Indiabulls Ventures Ltd. (Formerly Indiabulls Securities Limited) - [CIN IVL: L74999DL1995PLC069631] NSE CM[SEBI Reg No: INZ000007534] Mem No: 08756 | NSE F&O[SEBI Reg No: INZ000007534] BSE CM[SEBI Reg No: INZ000007534] Clearing No : 907 | BSE F&O[SEBI Reg No: INZ000007534] | NSE CDS [SEBI Reg No: INZ000007534] Indiabulls Commodities Ltd. - [CIN ICL: U74999DL2003PLC122874] SEBI Reg No: INZ000036136 | MCX: MEMBER CODE: 12835 | NCDEX: MEMBER CODE: 10 448-451, Udyog Vihar, Phase – V, Gurgaon – 122001, Phone: 022-61446300
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