Every other stock on NSE and BSE opens for continuous trading at 9:15. A newly listed IPO waits until 10:00. The first hour of its listing day is a special pre-open session: a call auction in which buy and sell orders are collected for up to 45 minutes and then matched at one equilibrium price, which becomes the stock’s opening price. That single number is what the market calls the listing price, and it is set by a fixed rulebook rather than by the first trade that happens to go through.
Key Takeaways
- The special pre-open session runs from 9:00 to 10:00 on an IPO’s first trading day: order entry to 9:45 (closing at a random moment after 9:35), matching to 9:55, then a five-minute buffer.
- The equilibrium price is the one that executes the most shares. Ties go to the smallest order imbalance, then to the price closest to the issue price.
- Once normal trading starts, the price band is 5% of the equilibrium price for issues up to ₹250 crore and 20% for larger ones.
- If no price is discovered, an IPO moves to the normal market with the issue price as its base.
- SME IPOs on NSE cannot open more than 90% above the issue price, a cap introduced in July 2024.
What Is the Special Pre-Open Session?
It is a one-hour call auction that SEBI extended to IPO and re-listed shares in January 2012, alongside a circular on trade controls for the normal session that follows. A call auction pools every order first and prints one price for all of them, instead of letting the first trade that happens to go through set the tone.
NSE runs it for three kinds of securities: IPOs, including SME IPOs, on their first trading day; re-listed shares on the day trading resumes; and stocks with derivatives contracts on the ex-date of a corporate restructuring such as a merger or demerger. BSE’s version covers IPOs and re-listed securities on the same timetable.
The Listing-Day Timetable
| Stage | Normal pre-open (all other stocks) | Special pre-open (IPO listing day) |
|---|---|---|
| Order entry, modification, cancellation | 9:00 to 9:10, closing randomly in the last 2 minutes | 9:00 to 9:45, closing randomly between the 35th and 45th minute |
| Order matching and trade confirmation | From close of entry to 9:12 | 9:45 to 9:55 |
| Buffer | 9:12 to 9:15 | 9:55 to 10:00 |
| Continuous trading begins | 9:15 | 10:00 |
| Order types | Limit and market | Limit only |
| Reference (base) price | Previous close | Issue price |
Timings from NSE’s pre-open and special pre-open pages (data as of October 2026). In the normal pre-open, market orders are allowed only until 9:05. BSE adds that orders in the special session must be fully disclosed, so iceberg-style orders using the revealed-quantity feature are rejected, and that there is no block-deal window on the listing day.
How the Equilibrium Price Is Chosen
For each possible price, the exchange adds up how many shares buyers would take at that price or lower and how many sellers would give up at that price or higher. The tradable quantity at that price is the smaller of the two. Then three tests run in order, per NSE:
- Maximum volume: the price that executes the largest number of shares wins.
- Minimum imbalance: if several prices tie on volume, the one leaving the smallest gap between unmatched demand and supply wins.
- Closest to base price: if that also ties, the exchange picks the price nearest the issue price. If the issue price sits exactly midway between the two candidates, the issue price itself is used.
No price band applies during the session. NSE instead uses an operating range agreed with other exchanges, which can be widened in steps of 10%, and orders outside it are frozen and later cancelled. Throughout order entry, BSE publishes an indicative opening price and matchable quantity at regular intervals, so bidders can watch where the price is heading before 9:45.
Worked Example: A ₹100 IPO on Listing Day
Take a hypothetical mainboard IPO priced at ₹100. When order entry closes, the book holds these limit orders. Buyers are willing to pay up to their price; sellers, mostly allottees, will accept their price or more. We ran the matching in Python.
| Price (₹) | Buy orders at this price | Sell orders at this price | Cumulative demand (≥ price) | Cumulative supply (≤ price) | Tradable shares | Imbalance |
|---|---|---|---|---|---|---|
| 105 | 0 | 3,000 | 28,000 | 3,000 | 3,000 | 25,000 |
| 110 | 8,000 | 4,000 | 28,000 | 7,000 | 7,000 | 21,000 |
| 115 | 6,000 | 6,000 | 20,000 | 13,000 | 13,000 | 7,000 |
| 118 | 4,000 | 5,000 | 14,000 | 18,000 | 14,000 | 4,000 |
| 120 | 5,000 | 6,000 | 10,000 | 24,000 | 10,000 | 14,000 |
| 125 | 3,000 | 5,000 | 5,000 | 29,000 | 5,000 | 24,000 |
| 130 | 2,000 | 0 | 2,000 | 29,000 | 2,000 | 27,000 |
₹118 executes 14,000 shares, more than any other price, so the first test settles it and the stock opens at ₹118. Everyone matched trades at ₹118, including the buyer who bid ₹130 and the seller who asked ₹105. That is the 18% listing gain the headlines would report. Note that ₹115 and ₹120 both had heavier order flow on one side; the auction rewards the price where the two sides overlap most, not the one with the loudest demand.
Orders That Don’t Match
At ₹118, sellers offered 18,000 shares and only 14,000 found buyers. The 4,000 left over, along with every buy order below ₹118 and every sell order above it, are not cancelled. For IPOs, NSE moves unmatched limit orders inside the operating range into the normal market at their own limit prices, keeping price-time priority. Someone who bid ₹110 is still in the queue at 10:00.
The Price Band That Applies From 10:00
SEBI’s January 2012 circular, as circulated to exchanges, ties the listing-day band to issue size and to the equilibrium price, not the issue price.
| Issue size | Listing-day band | Range in our example (₹118 open) | Other controls |
|---|---|---|---|
| Up to ₹250 crore | 5% of equilibrium price | ₹112.10 to ₹123.90 | Trade-for-trade segment for the first 10 days |
| Above ₹250 crore | 20% of equilibrium price | ₹94.40 to ₹141.60 | No trade-for-trade requirement in the circular |
Trade-for-trade means every buy must end in delivery, so intraday squaring-off is not possible during those ten days. BSE confirms that IPOs below ₹250 crore trade in that segment for their first ten days.
When No Price Is Discovered
If buy and sell orders never cross, there is no equilibrium price. For an IPO, the stock still moves to the normal market at 10:00 with the issue price as its base, and unmatched orders carry over at their limit prices. The band is then calculated on the issue price: 5% or 20% depending on issue size. Re-listed shares are treated more strictly. All their orders are cancelled and the call auction repeats on the next trading day, according to NSE.
SME IPOs: The 90% Ceiling
On 4 July 2024 NSE capped the opening price of SME IPOs in the special pre-open session at 90% above the issue price, effective immediately, to standardise price discovery across exchanges. The cap does not apply to mainboard IPOs. Had our ₹100 example been an SME issue on NSE’s Emerge platform, the opening price could not have exceeded ₹190, however aggressive the bids.
SEBI’s 2024 Changes to Stop Listing-Day Games
The 45-minute window had a weakness: orders could be placed to move the indicative price and then withdrawn just before the session closed, which SEBI treated as a manipulation risk. In June 2024 SEBI responded with a package that took effect about three months later, Business Standard reported:
- Random closure: order entry now ends at an unpredictable moment in the last ten minutes, so nobody knows which cancellation will be the last one allowed.
- Cancellation alerts: exchanges flag a client whose cancellations exceed 5% of the session’s total, or who cancels more than half of their own orders.
- Explanations on demand: exchanges can ask why orders were cancelled or prices modified.
- Public bid data: real-time order information is shown on exchange websites during the session.
What It Means If You Place an Order on Listing Day
- Use a limit price: market orders are not accepted in the session, so decide the highest price you would pay or the lowest you would sell at.
- Your limit is a ceiling, not the fill: if you bid ₹130 and the auction clears at ₹118, you pay ₹118.
- Don’t count on the last minute: because closure is random after 9:35, an order or cancellation placed at 9:40 may not get in.
- Check the issue size: it decides whether the stock can move 5% or 20% on day one and whether intraday trading is possible.
Dates matter elsewhere in a stock’s life too; our explainer on record date vs ex-date covers how corporate actions are timed, and more explainers sit in the Stocks section.
This article is for information and education only and is not investment, tax or financial advice. Figures were checked on 28 October 2026; confirm current details with the official source or a registered adviser before acting.
FAQ
What Time Does an IPO Start Trading on Listing Day?
Continuous trading starts at 10:00. From 9:00 to 9:45 orders are collected in the special pre-open session, and the opening price is set between 9:45 and 9:55.
How Is the Listing Price of an IPO Decided?
By call auction. The exchange picks the price that executes the most shares, breaking ties by the smallest imbalance and then by closeness to the issue price.
Can I Place a Market Order in the Pre-Open Session for an IPO?
No. Only limit orders are accepted in the special pre-open session. Market orders can be placed once normal trading starts at 10:00.
What Is the Upper Circuit on IPO Listing Day?
It depends on issue size: 5% above the equilibrium price for issues up to ₹250 crore and 20% for larger issues, with the same limit on the downside.
Why Can’t I Sell My SME IPO Shares Above 90% Gain at Open?
Since July 2024, NSE caps an SME IPO’s opening price at 90% above the issue price in the pre-open session. The stock can move further later, within its normal-market band.
Sources
- NSE: Special pre-open session
- NSE: Pre-open session
- BSE: Salient features of the special pre-open session
- SEBI: Trade controls in normal trading session for IPO and other scrips (20 January 2012)
- Calcutta Stock Exchange notice forwarding SEBI circular CIR/MRD/DP/02/2012
- Business Standard: SEBI tightens norms for IPO price discovery (20 June 2024)
- Business Standard: SME IPO opening price capped at 90% (4 July 2024)
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