BSE Rules Change: New rules will be applicable on Sensex for the first time from 8 December 2025- full details in circular

News Topical, Digital Desk : BSE has issued an important circular on the afternoon of 28 August 2025, according to which pre-open session will also start in index and stock futures (Equity Derivatives Segment) from 8 December 2025. Till now this facility was available only in the equity segment, but now traders will get the initial 15 minutes of pre-open in derivatives also.

What does it mean- The purpose of the pre-open session is to control the initial volatility and make better price discovery. Now the initial trading in F&O will also become more transparent and systematic. The exchange says that there will be no technical changes, the same API and data structure will work. Testing will start in a simulation environment from 6 October 2025.

In simple words, from December, the market opening experience will change for the investors and traders of the F&O segment and order discovery will be more smooth. What is a pre-open session?  The "pre-open session" of the stock market is a short time before the actual trading starts (usually 9:00 am–9:15 am). In this, investors have to place buy and sell orders.. These are matched, so that there is no sudden huge fluctuation as soon as the market opens and a fair price discovery can be done. Now BSE has announced that from 8 December 2025, this facility will also be applicable in index and F&O (futures and options). Why is it important for investors-  Understand the pre-open session as the "warm-up time" of the market. Players (investors) decide their positions before the real game (trading) begins. Better price discovery- In pre-open, the initial rate is decided on the basis of buying and selling. This makes the opening price more reliable and less volatile. Low volatility- Often, on big news (such as budget, results, international events), stocks jump and fall a lot as soon as the market opens. This shock is controlled to some extent by pre-open. Important for F&O traders- Now that this facility is coming in index and derivatives, it will be easier to understand the initial movement and set your strategy. Helps in technical analysis- Looking at the pre-open data gives a first glimpse of support and resistance, which is of great help to day traders.
 

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