NSE To Introduce Pre-Open Session In F&O From December: How Does It Affect Traders?

The National Stock Exchange of India (NSE) has announced that a pre-open trading window for the equity derivatives (F&O) segment will commence on Dec. 8, 2025. This new session will cover both single-stock and index futures within the derivatives market.

According to the NSE, the 15-minute pre-open window, running from 9:00 a.m. to 9:15 a.m., will follow a call auction framework and be divided into three separate parts.

Zerodha Varsity took to X to explain how it will affect traders. According to the free online education platform owned by Zerodha, intraday price action will not tell the whole story and the previous day's close should also be incorporated.

It added that if your trading approach relies on price movements during the initial n-periods of the market open, it’s important to factor in data from the pre-open session as well. Excluding this information could make intra-day volatility indicators appear less pronounced than they truly are.

“Since liquidity is usually thin during the pre-open sessions, price action should probably be capped, requiring tweaks to your trading strategy,” it added.

If your trading plan takes into account overnight developments such as decisions by the US Federal Reserve or the FDA, you’ll need to factor these in by taking part in the pre-open session, Zerodha Varsity suggested. 

“Once the pre-open session was introduced, the price discovery process, incorporating overnight news, started to occur before the open itself. This can be observed by measuring the gap between the previous closing price and the day's opening price…The same will be applicable to derivatives going forward,” Zerodha Varsity concluded.

The F&O pre-open window will operate between 9:00 a.m. and 9:15 a.m. It will follow a call auction structure. Traders can place, amend, or withdraw orders up to a randomly determined cut-off between 9:07 a.m. and 9:08 a.m., after which price discovery and trade matching will continue until 9:12 a.m.

A brief three-minute interval will then prepare the market for the regular trading session starting at 9:15 a.m.