Summary of this article
NSE and BSE will start pre-open session in derivatives from December 8
Trial runs will begin in October with mock sessions planned before the launch
Pre-open session aims to reduce opening volatility and improve price discovery in F&O
Stock market exchanges, National Stock Exchange (NSE) and Bombay Stock Exchange (BSE), proposed to introduce a pre-open session for index and stock derivatives (Futures and Options) segment from December 8, 2025 onwards.
"Changes related to pre-open session in the equity derivatives segment shall be made available for testing from October 6, 2025, in the test (simulation) environment," said BSE in a circular dated August 28, 2025. NSE will make this available by October 4, 2025.
Exchanges will also be conducting mock sessions for testing before going LIVE, and release other modalities related to implementation via a separate circular.
Why Are Exchanges Introducing Pre-Open Session In Derivatives
The market regulator Securities and Exchange Board of India (Sebi), earlier this year, on May 29, had released a circular mandating pre-open session for "current-month" stock and index futures contracts.
"The pre-open session to be extended to current-month futures contracts on both single stocks and indices, mirroring the modalities of the cash market's pre-open and post-closing sessions," said Sebi in its circular.
"In the last five trading days before expiry, these sessions shall extend to next-month futures contracts as liquidity shifts from one expiry to the other on account of rollover of futures contracts," the market regulator clarified.
What Happens During Pre-Open Session
In the cash segment, the pre-open session runs from 9:00 AM to 9:15 AM. In this period, according to the BSE website, orders are collected first and then matched, with all trades in a stock executed at a single opening price. Limit orders get priority over market orders, and all orders must be fully disclosed.
Unexecuted orders are carried into the regular trading session. If no trade happens in pre-open, the first trade in the continuous session sets the opening price. Exchanges also publish the indicative opening price, matchable quantity, and Sensex, Nifty 50 levels during the session. At the end of the pre-open session, opening values for all stocks and indices are released.
What Is In It For Traders
The first few minutes after the market opens are usually volatile, as traders price in overnight global cues and several domestic developments.
Introducing a pre-open session for equity derivatives segment, much like in the equity cash segment, would help in absorbing this volatility and lead to better price discovery.
