NSE Pre-Open Session Gets New Order Rules From 7 September; Here’s What Changes
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NSE will revise its pre-open session framework from 7 September 2026. The 15-minute session will remain unchanged, but order entry will be split into two phases. The changes are intended to align the opening price-discovery process with SEBI’s CAS.
The National Stock Exchange (NSE) will introduce a revised pre-open session structure from 7 September 2026. It will change how traders can place, modify and cancel orders before regular trading begins.
The overall session will continue from 9:00 am to 9:15 am, but its internal stages will be reorganised. Under the new framework, during the first five minutes, i.e, from 9:00 am to 9:05 am, both market and limit orders can be placed, modified or cancelled.
However, from 9:05 am to 9:10 am, only limit orders can be placed, modified or cancelled, while market orders will be rejected.
The revised mechanism is aimed at bringing the opening auction closer to the Closing Auction Session (CAS) framework introduced by the Securities and Exchange Board of India (SEBI).
A Two-Phase Order Entry Structure For NSE Pre-Open Session
From 7 September, the NSE pre-open session will operate through the following stages:
Phase 1 | 9:00 am-9:05 am | Market and limit orders can be placed, modified or cancelled |
Phase 2 | 9:05 am-9:10 am | Only limit orders can be placed, modified or cancelled; market orders will be rejected |
Order Matching | 9:10 am-9:12 am | Orders are matched, and the opening price is determined |
Buffer Period | 9:12 am-9:15 am | Orders transition to the continuous trading session (CTS) |
The exchange may randomly close order entry during the final two minutes of the second phase. The order-matching period will also begin at 9:10 am, instead of the current 9:08 am.
The pre-open session follows a call auction mechanism. It covers securities across the equity market, including small and medium-sized enterprise (SME) securities, partly paid-up securities, infrastructure investment trusts (InvITs) and real estate investment trusts (REITs).
Opening Price Discovery Will Mirror The Closing Auction Framework
The changes are designed to align the opening price-discovery process with the CAS, which was introduced in the equity cash market on 4 August 2026. The broader objective is to create greater consistency between the mechanisms used to determine opening and closing prices.
The modifications are also meant to better align the cash and derivatives segments and to facilitate more efficient market functioning. The CAS framework itself is aimed at making the closing price discovery more visible and robust. It will also facilitate more efficient execution of large orders and reduce tracking errors for passive funds.
Also Read - SEBI To Reassess Derivative Settlement Price Rules After CAS Launch
This article is for informational purposes only and should not be considered investment advice from Kotak Neo. For compliance T&C and disclaimers, Visit www.kotakneo.com/disclaimer
Vishwa has spent 10+ years across fintech and FMCG doing what most people miss, connecting the dots, catching trends before they trend, and finding the angle nobody else thought to ask about.
At Kotak Neo, she drives content strategy for neoshorts, Kotak News Desk, and Investing Guide, turning market noise into something worth reading.
When she's not decoding markets, she trades charts for canvases, chasing art, painting, and architecture across cities she's yet to explore.
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