NSE BSE pre-open session timings have been revised from today, September 7, 2026, with changes to the order-entry and order-matching phases of the Pre-Open Auction Session. The overall pre-open session will continue to operate from 9:00 AM to 9:15 AM, the order-entry and order-matching stages within this 15-minute window have been restructured.
The changes are aimed at aligning the Pre-Open Auction framework with the Closing Auction Session (CAS) and modifying the existing auction mechanism for the opening of the trading day. NSE’s circular, issued on July 1, states that the revised framework has been introduced in line with SEBI’s directions regarding the introduction of the Closing Auction Session and modifications to the Pre-Open Auction Session.
NSE BSE Pre-Open Session Timings: What Changes From Today?
Under the earlier framework, the order-entry period ran from 9:00 AM to 9:08 AM, followed by order matching and trade confirmation from 9:08 AM to 9:12 AM. The final three minutes, from 9:12 AM to 9:15 AM, served as a buffer period.
With the revised structure coming into effect today, the order-entry period is divided into two phases of five minutes each.
| Session | Previous Time | Revised Session |
|---|---|---|
| Order Entry – Phase 1 | 9:00 AM – 9:08 AM* | 9:00 AM – 9:05 AM – Limit and market orders can be entered, modified and cancelled |
| Order Entry – Phase 2 | — | 9:05 AM – 9:10 AM* – Only limit orders can be entered, modified and cancelled; market orders are restricted |
| Order Matching & Trade Confirmation | 9:08 AM* – 9:12 AM | 9:10 AM – 9:12 AM* – Opening price determination, order matching and trade confirmation |
| Buffer Period | 9:12 AM – 9:15 AM | 9:12 AM – 9:15 AM – No change; transition to continuous trading |
*The order-entry period is subject to system-driven random closure during the last two minutes. The NSE circular states that the order-matching period will begin immediately after the completion of the order-entry period.
Market orders restricted after 9:05 AM
One of the most significant changes for investors is the restriction on market orders after 9:05 AM.
During the first five minutes, from 9:00 AM to 9:05 AM, both market and limit orders will be permitted. From 9:05 AM to 9:10 AM, only limit orders will be allowed. Any market order placed after the restriction begins will be rejected by the exchange with an appropriate error message.
Algo market orders will also be permitted during the initial five-minute period when both market and limit orders are allowed.
For investors and traders, the change makes the first five minutes of the Pre-Open Session particularly important when a market order is intended to participate in the opening price discovery process.
Revised order-matching priority
The revised framework also changes the priority for order matching during the Pre-Open Session. Under the NSE framework, market orders will receive priority over limit orders.
Eligible market orders will first be matched with other eligible market orders according to time priority at the equilibrium price. Any residual eligible market orders will then be matched with limit orders based on price-time priority. Remaining limit orders will subsequently be matched with other limit orders according to price-time priority.
This revised sequence is part of the broader changes being introduced to the Pre-Open Auction framework.
Changes applicable to equity derivatives too
The revised Pre-Open Auction framework is also being implemented in the Equity Derivatives (F&O) segment from today. NSE’s F&O circular specifies the same 15-minute Pre-Open Session from 9:00 AM to 9:15 AM, with the revised order-entry and order-matching phases.
In the derivatives segment as well, market orders are permitted during the initial five minutes and become restricted from 9:05 AM onward. The order-matching period runs from 9:10 AM to 9:12 AM, followed by the unchanged buffer period until 9:15 AM.
What should investors know?
The revised framework does not change the overall 9:00 AM to 9:15 AM Pre-Open window. Instead, it changes the manner in which orders can be entered and matched within that period.
Investors should particularly note that market orders are available only from 9:00 AM to 9:05 AM, while the 9:05 AM to 9:10 AM phase permits limit orders only. The 9:12 AM to 9:15 AM buffer period remains unchanged.
With the revised framework now effective from today, September 7, 2026, investors and traders should take note of the new order-entry phases and plan their Pre-Open orders accordingly.
Kaashika is a social media strategist and financial content creator at Lakshmishree. She specialises in simplifying complex IPO and stock market concepts into clear, easy-to-understand content. Having created over 500+ pieces of financial content across reels, blogs, website posts and digital creatives, Kaashika helps audiences connect with the world of finance in a more accessible and engaging way.
