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.
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
Example: If December 2025 contracts expire on 30 Dec 2025, the pre-open session applies to all December futures throughout the month and to January 2026 contracts during the final five trading days before expiry.
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.
ProStocks Client Tip: Clients can place limit orders during the pre-open session. Ensure margins are funded before 9:00 AM to avoid rejections.
