What is the F&O pre-open session on NSE?
The F&O pre-open is a 15-minute call-auction window conducted before the normal derivatives market opens, designed to establish a fair and transparent opening price through order matching.
What are the timings of the Equity Derivatives pre-open session?
- Order Entry: 9:00 AM – 9:08 AM (random closure between 7th–8th minute)
- Order Matching & Trade Confirmation: 9:08 AM – 9:12 AM
- Buffer: 9:12 AM – 9:15 AM (transition to continuous trading)
Which contracts are covered in the derivatives pre-open?
This session applies to current-month index and single-stock futures. During the final five trading days before expiry, it extends to next-month futures to aid rollover and liquidity. Options and spread contracts are not included.
How is the opening price discovered in pre-open?
- The opening price is determined at the level where maximum executable volume can occur.
- If multiple prices qualify, the system selects the one with the minimum imbalance, or the price closest to the previous close.
- If no price is discovered, the first trade in the normal session becomes the day’s opening price.
Order types and margin validation
- Clients can place limit orders during the F&O pre-open session.
- All orders are validated for margin sufficiency before acceptance by the exchange.
- Unmatched limit orders will move to the normal market retaining their original timestamps.
- Sq off order will be subject to margin as if this is fresh position during pre open.
- Once pre open is over this additional margin will be dropped.
For Details Kindly refer exchange circular NSE/FAOP/71092
What operational policies apply?
- Self-Trade Prevention Check (STPC) remains active during the order entry period.
- Trade cancellations are not permitted for pre-open trades.
- Cancel on Logout (COL) and Kill Switch functions are not applicable in the pre-open session.
When is the pre-open session not applicable?
- On ex-dates of corporate actions due to a scheme of arrangement for the underlying security.
- To options, spread orders, and other special order types.
Example: Understanding the last-five-days rule
Comprehensive FAQs
Is participation mandatory?
No, the session runs exchange-wide but participation is voluntary.
Will indicative prices be visible?
Yes, indicative equilibrium price and quantity data are disseminated during order entry.
Can I use stop-loss or special order types?
No, stop-loss (SL) and special order types are not permitted during the pre-open session.
How should traders prepare?
Ensure margins are available before 9:00 AM, review rollover positions, and plan entries based on indicative prices published by the exchange.