The National Stock Exchange (NSE) has introduced a pre-open session for the equity derivatives (F&O) segment starting from December 8, 2025. The pre-open session will be applicable for both single stocks and indices futures in the equity derivatives market.
The pre-open session will be conducted using a call auction mechanism for a duration of 15 minutes i.e., from 9:00 am to 9:15 am, said. This 15-minute session will be split into three components:
Order Entry Period: 9:00 AM – 9:08 AM: Traders can place, modify, or cancel orders during this period. A system driven random closure will take place in this phase between the 7th and 8th minute. The random closure of equity segment pre-open and equity derivatives segment pre-open will be independent.
Order Matching & Trade Confirmation: 9:08 AM – 9:12 AM: The order matching period will start immediately after completion of the order entry period. The system will determine the opening price based on the equilibrium price and match orders accordingly.
Buffer Period: 9:12 AM – 9:15 AM: This period will be a transition from pre-open to continuous trading session.
Eligible Contracts
The pre-open session will be applicable to current-month futures on both single stocks and indices. In the last five trading days before the current month expiry, this session will be extended to next month futures contracts.
It is to be noted that the pre-open will not be applicable for Far month (M3) expiry contracts, spread and option contracts on indices and stocks, or futures on ex-dates due to corporate actions.
The market parameters for the pre-open derivative segment are similar to those of the normal market, including tick size, lot size, and price bands.
Trading session
Pre-open session comprises two sessions – Order Collection Period and Order Matching Period.
During the Order Collection Period, orders can be entered, modified, and cancelled. Both Limit and market orders are allowed. However, special term orders like Stop loss and IOC are not allowed. Indicative prices, equilibrium data, and demand-supply statistics will be disseminated to participants in real-time.
In the Order Matching Period, the system will match the order at a single equilibrium price which will be the open price. The order matching will happen on a defined sequence — limit orders with limit orders, residual limit orders with market orders, and market orders with market orders. During this period, order modification, order cancellation, trade modification and trade cancellation are not allowed.
All orders received in pre-open session shall be validated at the applicable margins for sufficiency of available capital prior to acceptance of the orders. If the available capital of the member is insufficient to cover the margin requirement of the order placed, the same shall not be accepted for the pre-open session, NSE said.
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