How share prices are set
Orders, the queue, the opening and closing auctions, and how a new share gets its first price
Rules as on 12 October 2026
Verified 12 October 2026
For training and education only. Not investment advice.
Trainer notes
Ask the room: who decides the price of a share at 11:00 am on a trading day? Typical answers are 'the company', 'the exchange' or 'the market'. Keep them for slide 2. This deck uses no market prices; every price in it is invented.
A share price is the price of the latest trade. Nobody announces it. A buyer and a seller agree on it.
The exchange only runs the queue. It lines up buy orders and sell orders and matches them by fixed rules. Each match is a trade, and the latest trade is the price on the screen.
Trainer notes
This is what 'price discovery' means: the price is found by orders meeting, not fixed by anyone. Profits, news and mood matter because they change the prices at which people are willing to buy or sell.
Four terms behind every price
Bid
The price a buyer is willing to pay. The highest bid in the market is the best buy order.
Offer
The price a seller is willing to accept, also called the ask. The lowest offer is the best sell order.
Limit order
An order with a price attached. It trades only at that price or a better one.
Market order
An order with no price attached. It trades at the best price obtainable when it is entered.
Take-away: Best price first. At the same price, the earlier order first. This is called price-time priority.
Source: NSE, 'Trading System' page for the equities segment (order types, order matching rules), opened 12 Oct 2026.
Trainer notes
The list of waiting buy and sell orders is called the order book. Investors place orders through a stock broker; the exchange's system does the matching and does not show who is on the other side.
One order moves the price
THE ORDER BOOK
Last trade: ₹200.
Waiting sell orders: 100 shares at ₹201 and 200 shares at ₹202.
A new order arrives: buy 250 shares, limit ₹202.
- The best sell order goes first: 100 shares trade at ₹201. Cost: 100 × ₹201 = ₹20,100.
- The buyer still needs 150 shares. They trade at ₹202. Cost: 150 × ₹202 = ₹30,300.
- Total paid: ₹20,100 + ₹30,300 = ₹50,400 for 250 shares. Average: ₹50,400 ÷ 250 = ₹201.60 a share.
- The latest trade was at ₹202, so the screen now shows ₹202. Fifty shares are still on offer at ₹202.
Result: The price moved from ₹200 to ₹202 because of one order. No one announced it; trades made it.
Illustration with an invented share and assumed orders. Brokerage and other charges are left out.
Trainer notes
Two lessons. First, the price changes only when a trade happens at a different price. Second, one order can trade at more than one price, so the buyer's average (₹201.60) is not the price on the screen (₹202).
9:00 to 9:15 am: the pre-open session
A 15-minute auction that finds one opening price for each share it covers. In force from 7 Sep 2026.
9:00 to 9:05 am
Orders are collected, not matched. Limit and market orders can be placed, changed or cancelled.
9:05 to 9:10 am
Only limit orders can be placed. Entry stops at a random moment between 9:08 and 9:10 am.
9:10 to 9:12 am
The exchange finds one price, the equilibrium price, and matches all the orders it can at that price.
9:12 to 9:15 am
Orders still unmatched move to continuous trading, keeping their place in the queue.
Source: SEBI circular of 16 January 2026 (closing auction session and changes to the pre-open session), para 5 and 6.2; NSE 'Pre-Open Session' page, updated 4 Sep 2026.
Trainer notes
The stop time is random and system-driven. Stop-loss orders and orders that show only part of their quantity are not allowed in the pre-open. If no price is found in the pre-open, the first trade in the normal market gives the opening price.
Finding the opening price
ORDERS AT THREE PRICES
At ₹99: buyers want 900 shares, sellers offer 400.
At ₹100: buyers want 700, sellers offer 600.
At ₹101: buyers want 300, sellers offer 800.
- At ₹99, only 400 shares can trade, because sellers offer no more than that.
- At ₹100, 600 shares can trade. At ₹101, only 300 can, because buyers want no more.
- The most shares can trade at ₹100. That is the equilibrium price, and it becomes the opening price.
- All 600 shares trade at ₹100. Buy orders for the other 100 shares stay in the queue.
Result: The opening price is the single price at which the largest number of shares can change hands.
Illustration with assumed orders. If two prices tie, the exchange applies further tie-break rules.
Trainer notes
Tie-breaks, in order: the price with the smallest unmatched quantity, then the price closest to the previous day's closing price. The same method is used in the closing auction, with a reference price in place of the previous close.
3:15 pm onwards: the closing price
Closing auction
Since 3 August 2026, shares that have derivatives get their closing price from an auction held from 3:15 to 3:35 pm. It also finds one equilibrium price.
Other shares
For the remaining shares, the closing price is the volume-weighted average price of trades in the last 30 minutes of continuous trading.
Why the close matters
The closing price is the reference for index values, for settling derivatives and for the net asset value (NAV) of mutual fund schemes.
Source: SEBI circular HO/47/11/11(3)2025-MRD-POD2/I/2765/2026 dated 16 January 2026, paras 1, 2.2, 4.1, 4.2 and 6.1.
Trainer notes
Derivatives here means futures and options contracts on the share. In the closing auction, orders must be within 3% either way of a reference price, the volume-weighted average price of trades from 3:00 to 3:15 pm. If no equilibrium price is found, the reference price is the close. SEBI's consultation paper of 12 Sep 2026 proposes changes to timings and derivative settlement; none was final on 12 Oct 2026.
Limits on how far a price can move
Daily price bands
Many shares have a daily price band of 2%, 5%, 10% or 20% either way. The exchange assigns the band share by share.
Shares with derivatives
No daily price band applies to them. The exchange instead sets an operating range of 10% to keep out orders at non-genuine prices.
Market-wide breakers
If the Nifty 50 or the Sensex moves 10%, 15% or 20% either way, trading in equity and equity derivative markets nationwide is usually halted.
Source: NSE, 'Price Bands' page (updated 12 Jan 2023) and 'Circuit Breakers' page (updated 4 Feb 2020), both opened 12 Oct 2026.
Trainer notes
The length of a market-wide halt depends on the level and the time of day. A 10% move at or after 2:30 pm brings no halt; a 20% move at any time stops trading for the rest of the day. After a halt the market reopens with a pre-open auction. The trigger is whichever of the two indices is breached first.
Before listing: book building
An initial public offer (IPO) is a company's first sale of shares to the public. Bids find its price.
A price band is set
The company and its lead managers announce a floor and a cap. The cap can be at most 20% above the floor.
Investors bid
While the issue is open, investors bid for shares at prices within the band.
The price is fixed
The final price, the cut-off price, is decided from the demand in the bids. Retail investors may bid 'at cut-off'.
Trading begins
On listing day a special pre-open session from 9:00 to 10:00 am finds the first market price.
Source: SEBI investor education website, 'Book-building Process'; NSE FAQ on the Special Pre-Open Session, version 6.1, April 2026.
Trainer notes
A retail investor who bids 'at cut-off' agrees to pay whatever final price is discovered. The first market price can be above or below the issue price; the issue price gives no assurance about it. In the special session only limit orders are accepted, and order entry closes at a random moment between 9:35 and 9:45 am.
If you learnt this from older material
The matching rule has not changed. The opening, the close and settlement have.
What a 2013-15 deck says
- Every share's close is the volume-weighted average of its last half hour's trades.
- A trade is settled two working days later (T+2).
- Price discovery is explained through profits and mood, not orders.
What holds in October 2026
- Shares with derivatives close by auction, 3:15 to 3:35 pm, since 3 Aug 2026.
- Trades settle the next working day (T+1). A same-day (T+0) cycle also exists.
- Pre-open changed on 7 Sep 2026: market orders accepted only until 9:05 am.
Source: SEBI circular of 16 Jan 2026; NSE 'Settlement Cycle' page, opened 12 Oct 2026. T+2 as the earlier cycle: SEBI circular of 7 Sep 2021, read in a secondary summary.
Trainer notes
T is the trade day. In T+1, shares and money change hands on the next working day. The T+0 cycle is optional and offered for a limited set of shares. Profits and mood still matter; they work through the orders people place.
Four things people get wrong
Misconception'The company sets its share price.'
What is trueAfter listing, the company has no say. The price is whatever the latest buyer and seller agreed on the exchange.
Misconception'More buyers than sellers.'
What is trueEvery trade has a buyer and a seller for the same shares. A price rises when buyers agree to pay more.
Misconception'The price on screen is my price.'
What is trueThe screen shows the latest trade. A market order trades at the best prices then on offer, which may differ.
Misconception'The IPO price is the market price.'
What is trueThe issue price comes from bids before listing. The market price starts with the listing-day auction.
Trainer notes
On the second point: the number of shares bought always equals the number sold. What changes is how keen each side is, which shows up in the prices of the orders. Do not describe any price as cheap or expensive.
Check yourself
Question 1: Waiting sell orders: 50 shares at ₹301 and 100 at ₹303. You place a market order to buy 120 shares. What do you pay in all, and what price does the screen then show?
Answer: 50 × ₹301 = ₹15,050 and 70 × ₹303 = ₹21,210. Total ₹36,260, an average of about ₹302.17 a share. The latest trade was at ₹303, so the screen shows ₹303.Question 2: In a pre-open auction, 500 shares can trade at ₹150, 800 at ₹151 and 650 at ₹152. What is the opening price, and why?
Answer: ₹151. It is the price at which the largest number of shares (800) can trade, so it is the equilibrium price.Question 3: A client asks: 'Who decided today's closing price of this share?' What would you say?
Answer: No person decided it. If the share has derivatives, the close came from the closing auction held from 3:15 to 3:35 pm. For other shares it is the volume-weighted average price of trades in the last 30 minutes of continuous trading.
Sources and disclaimer
Sources for the figures in this explainer
- Closing auction (3 Aug 2026), pre-open timings (7 Sep 2026), uses of the closing price: SEBI circular dated 16 January 2026, HO/47/11/11(3)2025-MRD-POD2/I/2765/2026.
- Order types, price-time priority, equilibrium price and unmatched orders: NSE 'Trading System' and 'Pre-Open Session' pages (pre-open page updated 4 September 2026).
- Price bands and market-wide circuit breakers: NSE 'Price Bands' page (updated 12 January 2023) and 'Circuit Breakers' page (updated 4 February 2020).
- Book building: SEBI investor education website, 'Book-building Process'. Listing-day session: NSE FAQ on the Special Pre-Open Session, April 2026.
- T+1 and T+0 settlement: NSE 'Settlement Cycle' page, opened 12 October 2026.
- All shares, orders and prices in the worked examples and quiz are invented for illustration.
This material is for training and investor education only. It is not investment, tax or legal advice and is not a recommendation to buy, sell or hold any security or scheme. Examples use assumed figures unless a source and date are shown. Mutual fund investments are subject to market risks; read all scheme related documents carefully. Trustner Asset Services Pvt. Ltd. is an AMFI-registered Mutual Fund Distributor (ARN-286886).