Stock Market Timings & Auctions

It is 7:40 on a Monday morning and Maya's kitchen is quiet: the griddle is cold and prep starts at ten. She opens her broker's app to look at ICICI Bank, the bank she has been reading about, and the Buy button works.

Two clocks decide when a trade can happen. The first is the clock of the day: the exchange's sessions, in India time (IST), five and a half hours ahead of UTC, with no summer change. The second is the calendar: which days are trading days at all. SEBI and the exchanges set both by circular: show the note on Circular, a numbered notice, and both change. In 2026 alone, a closing auction began on 3 August, a new pre-open started on 7 September, a later, shorter closing auction starts on 7 December, and Thursday 15 January was added as a trading holiday a month after the year's list came out.

The main session runs from 9:15 am to 3:30 pm, Monday to Friday, and outside the sessions nothing trades. Your broker can hold an order you save until the exchange opens (chapter 6). India's share market has no evening session: the closing auction is done by about 3:40 pm from 7 December 2026 (3:35 pm until then), and the only trading after it is the ten-minute post-close: show the note on Post-close session, 3:50 to 4:00 pm, at the day's closing price (chapter 5). The US is different, as chapter 8 shows.

A third calendar decides when the shares and the money actually move after a trade: settlement. It keeps its own holidays and has its own lesson, Clearing & T+1 Settlement, next in the course; this one stays with the clock.

Four terms first, because the day's timetable uses all of them. Futures and options (F&O) are contracts whose value comes from a share (What You Can Buy shows them in one picture). This lesson needs only one thing about them: whether a share has them decides how it closes. Continuous trading is the main session, when each order is matched the moment it meets another. The closing auction session (CAS) is a short auction at the end of the day that sets the close of shares with F&O. The post-close session is the last ten minutes, when trades happen only at the closing price.

The day, in order, from Monday 7 December 2026: 8:45 to 9:00 am, the morning block deal window (chapter 7). 9:00 to 9:15 am, the pre-open auction: orders come in until a random moment between 9:08 and 9:10, one match is done by 9:12, and the last three minutes hand over to the main session (chapter 3). 9:15 am, continuous trading begins (chapter 4). 2:05 to 2:20 pm, the afternoon block deal window. 3:30 pm, continuous trading ends for every share, and a share without futures and options closes at the average price of its last half-hour. 3:30 to 3:40 pm, the closing auction for shares with futures and options, whose close is the auction's one price. 3:45 pm, futures and options contracts stop trading (expiring index contracts stop at 3:30 pm on their expiry day). 3:50 to 4:00 pm, the post-close, where trades happen only at the closing price.

Until Friday 4 December 2026 the end of the day is shaped differently, and every real day in this lesson ran on that timetable: shares with futures and options stop continuous trading at 3:15 pm and close in an auction from 3:15 to 3:35 pm, and the contracts trade until 3:40 pm. Only the end of the day changes on 7 December; the morning is the same on both timetables.

Which rule is yours? If a share has futures and options on it, it closes by auction; your app usually shows a futures contract for it. ICICI Bank does: it is on NSE's F&O list, which had 218 shares: show the note on Shares on NSE's F&O list on 30 October 2026. The trucks and buses company of Tata Motors (NSE: TMCV) is not on it, so its close is still the last half-hour's average. NSE adds and drops shares from time to time, so the list is checked on the day, not remembered.

The times come from circulars, and they change. SEBI's circular of 15 October 2026, forwarded by NSE the next day, moves the closing auction to 3:30 to 3:40 pm from Monday 7 December 2026, four months after the auction began. When an exchange's web page and a newer circular differ, the circular wins: show the note on Which notice applies.

The pre-open session runs in four steps, from 7 September 2026. From 9:00 to 9:05 am, limit and market orders can be entered, changed or cancelled. From 9:05 to 9:10, limit orders only; entry stops at a random moment between 9:08 and 9:10, so nobody can wait for the last second. Matching runs to 9:12, and 9:12 to 9:15 hands the day to continuous trading. Only two kinds of order are accepted: a limit order, which names the highest price you will pay or the lowest you will accept, and a market order, which takes whatever price the market finds (Placing Your First Order compares the order types). Stop-loss orders are not accepted in the pre-open.

While orders come in, nothing trades. Your screen shows an indicative price, the total quantities that buyers and sellers have entered, and the imbalance between them, and all of it changes until entry stops. The indicative price is a forecast of the auction, not the open.

How is one price found? Think first: buyers want a low price and sellers a high one, so at a very low price many want to buy and few will sell, and at a very high price the reverse. The open sits where the two meet. The exchange checks it price by price: at each possible price it counts the shares buyers will take at that price or higher and the shares sellers will give at that price or lower. The smaller of the two is what can trade there. The price where that number is largest becomes the opening price. If two prices tie, the one that leaves the fewest shares unmatched wins, then the one nearest yesterday's close. Market orders are matched first. If no price is found, the first trade after 9:15 sets the open.

Say Maya, at 9:03 am on Monday 19 October 2026, enters a limit buy for 3 ICICI Bank shares at up to ₹1410.00 (an illustration). ICICI Bank's opening price that day was ₹1405.00, ₹8.00 or 0.57% above Friday's close of ₹1397.00. Every order matched in the auction trades at its one price, so she pays 3 × ₹1405.00 = ₹4215.00: show the note on Maya's 3 ICICI Bank at the open, not ₹4230.00, and a seller who would have taken less also receives ₹1405.00. A limit is the worst price you accept, not the price you pay.

Orders that did not match move into continuous trading at 9:15, keeping their original time stamp. The auction is not only for the largest companies: since April 2013 it has covered every share in the normal market except a short list of very thinly traded ones, and on 28 October 2026 NSE's pre-open screen listed 2179 securities: show the note on Who is in the pre-open. A share on its listing day has a longer special pre-open, 9:00 to 10:00 am (IPOs Explained). New York's NYSE also opens its listed shares with an auction, at 9:30 am New York time.

Why an auction, and not a race at 9:15? News arrives while the market is shut. On the evening of Monday 10 March 2025, after the close, IndusInd Bank told the exchanges it had found discrepancies in some account balances of its derivatives portfolio, an estimated hit of about 2.35% of its net worth. Orders sent overnight could not trade until the next morning. Tuesday's first price was ₹810.45, 10.0% below Monday's ₹900.50 close, and the share never traded higher that day; it closed at ₹655.95, 27.2% lower. Nobody traded at Monday's price once the news was out. That is the auction's job: the night's orders, and the news behind them, meet in one price instead of a race at 9:15. Why news moves prices is What Moves Share Prices; what such a gap does to a stop-loss is in Risk Management 101.

From 9:15 am each new order is matched at once against the best waiting order: the best price first, then the earliest order at that price (How a Stock Exchange Works shows the matching). An order that finds no match waits in the book. The usual kind is a day order, valid until the end of the trading day; the other validities are in Placing Your First Order.

One order's day, an illustration on real prices. Say Maya places a day limit buy for 3 ICICI Bank shares at ₹1375.00 at 10:30 am on Monday 19 October 2026. ICICI Bank traded between ₹1377.90 and ₹1411.80 that day, so no seller ever came down to her price, and her order waited, unfilled.

Then comes the handover. For a share with futures and options, continuous trading stopped at 3:15 pm that day (3:30 pm from 7 December 2026). The exchange works out a reference price: show the note on Reference price, the average price of the last 15 minutes of trading, weighted by quantity. Unfilled limit orders priced within 3% of it are carried into the closing auction, ahead of orders placed there; stop-loss orders and orders outside that band are not. NSE's daily files do not show the reference itself, but an average of the day's trades must lie inside the day's range, so the band's lower edge lay somewhere between ₹1336.56 and ₹1369.45: show the note on Highest the band's lower edge could be. Maya's ₹1375.00 was carried whatever the exact reference; a buy at ₹1330.00 would not have been. The auction closed at ₹1381.00, above her limit, so it found her no seller either.

A share without futures and options, such as TMCV, has no closing auction to carry an order into: it trades until 3:30 pm, and its unfilled day orders stop there.

Either way, the day's end is the order's end. Nothing rolls into tomorrow by itself: if Maya still wants the shares on the next trading day, she places the order again. Some brokers offer longer-lived instructions of their own, which Placing Your First Order explains.

There are two rules, and the share decides which one applies. Rule one, for a share with futures and options: the closing auction session, run like the morning's auction. From Monday 7 December 2026, at 3:30 pm the reference price is set and waiting orders are carried in; from 3:31 to 3:36 limit and market orders come in; from 3:36 to 3:40 limit orders only, with a random stop between 3:38 and 3:40; then one match at one price, published as soon as it is done. From 3 August to 4 December 2026 the same steps ran from 3:15 to 3:35 pm, the auction of every real day in this lesson. Orders must sit within 3% of the reference, and stop-loss orders are not allowed. The price is found as at the opening; if no price is found, the reference price becomes the close. Rule two, for every other share: the close is its volume-weighted average price (VWAP): show the note on VWAP from 3:00 to 3:30 pm, each trade's price counted by the number of shares it moved.

NSE's own data shows the difference. From 14 to 31 July 2026, while ICICI Bank still closed by the average, its last trade and its official close differed on 13 of 14 sessions: show the note on ICICI Bank, 14 to 31 Jul 2026: on Friday 17 July the last trade was ₹1454.00 and the close ₹1444.30; on Tuesday 28 July, ₹1417.60 and ₹1430.80. From Monday 3 August, when its close moved to the auction, the two were the same number on every one of the 61 sessions to 29 October (3 August: ₹1460.00 and ₹1460.00), because the day's last trades now happen at the auction's one price. On 19 October, ICICI Bank's last trade and close were both ₹1381.00, while TMCV, which has no futures, last traded at ₹418.45 and closed at ₹418.75.

The average, worked on made-up trades: 1000 shares at ₹500.00, 2000 at ₹502.00, 500 at ₹498.00 and 1500 at ₹501.00 add up to ₹2504500 for 5000 shares, so the close is ₹2504500 ÷ 5000 = ₹500.90. Big trades count for more. A last trade of 10 shares at ₹499.00 leaves it at about ₹500.90: one small last trade cannot drag the close.

Why SEBI moved F&O shares to an auction (among the reasons in its circular of 16 January 2026): an auction pools the day's last orders into one price that everyone can join on equal terms; index values and mutual fund prices (NAVs) are worked out from the close; and index funds can buy or sell at that exact price.

In the post-close, 3:50 to 4:00 pm, orders trade only at the closing price, so nothing there can move it. The close is no promise about tomorrow either: the next morning's auction starts again from every order. Tomorrow's quote page calls this number the previous close (How to Read a Stock Quote).

New York works the same way at the end of its day: the NYSE closes its listed shares with an auction at 4:00 pm New York time.

The market is shut for a holiday, but the restaurant is not. After the dinner rush, with the chairs up and the griddle cooling, Maya has a quiet minute, and an order she has been meaning to place.

An after-market order (AMO): show the note on After-market order is a broker's service, not an exchange session. The exchange takes its first orders of the day at 9:00 am, in the pre-open (block deals aside); until then the order is a note with the broker. Each broker sets its own AMO window and the order types it accepts. Maya's broker, Sahi, takes AMOs from 3:30 pm and sends stock AMOs into the pre-open at 9:00 am on the next trading day; its help page describes them as limit orders. Another large broker takes them from 4:00 pm to 8:58 am, with the same 9:00 am hand-over.

One night and morning, an illustration on real prices. On Tuesday 20 October 2026, Dussehra, at 9:40 pm, Maya saves: buy 3 ICICI Bank, limit ₹1400.00, day order, AMO. The exchange has not seen it. On Wednesday 21 October at 9:00 am, Sahi sends it into the pre-open, where it joins the opening auction. The auction's price was ₹1406.00, above her limit, so her order did not fill at the open; it moved into continuous trading with its time stamp and waited.

Later the price came down to her: the day's low was ₹1383.00. A buy waiting at ₹1400.00 is filled before any trade can happen at a lower price, so she bought 3 at ₹1400.00, ₹4200.00 in all. A market order, at a broker that takes market AMOs, would instead have bought at the opening price: 3 × ₹1406.00 = ₹4218.00: show the note on A market AMO, 3 ICICI Bank, which is ₹75.00 more than three shares at Monday's ₹1381.00 close. Either way, she learns whether the morning auction filled her only once it has matched, by about 9:12 am.

Limit or market, side by side: a limit AMO protects the price and may not fill; a market AMO fills at whatever the auction finds, even on a morning like IndusInd Bank's in chapter 3. An AMO never trades at last night's price just because it was saved last night.

An order for crores of shares sent into the normal book would eat through the waiting orders and move the price against its own owner. A block window lets a buyer and a seller who have already agreed trade in one transaction, in SEBI's words "without putting either the buyer or seller in a disadvantageous position".

A block deal, under the rules in force since December 2025, uses one of two windows: 8:45 to 9:00 am, where the reference is the previous close, or 2:05 to 2:20 pm, where it is the average price of trades from 1:45 to 2:00 pm. The price must be within 3% of that reference, and never beyond the day's price band. The order must be worth at least ₹25 crore; market orders are not allowed; and an order matches only another with the same price and the same quantity (NSE's own example: a buy of 100000 shares at ₹1000 does not match two sells of 50000 at ₹1000), so a block is never partly filled. Every block must end in delivery, and the exchange publishes the share, the client, the quantity and the price the same day, after market hours.

On ICICI Bank's numbers, the morning window of 19 October 2026 had a reference of ₹1397.00, so a block could be priced from about ₹1355.09 to ₹1438.91. ₹25 crore at ₹1397.00 is at least 178955 shares, about 59000 times Maya's ₹4215.00 order.

A bulk deal needs no special window. When one client's buying or selling in one share passes 0.5% of the company's listed shares in a day, the deal is disclosed and published, so that rumours do not fill the gap.

Reading a real report. NSE's block deals for Thursday 8 October 2026 list Reliance: a buy by PI Opportunities AIF V LLP of 2040212 shares at ₹1176.00, and the same trade as a sale by Pioneer Investment Fund Scheme II. One trade, worth about ₹239.93 crore: show the note on One Reliance block, 8 Oct 2026, 2.6% below the previous close of ₹1207.70, inside the 3% limit. The same two funds traded blocks in four other companies that day, ICICI Bank among them. The report says who, how much and at what price; it never says why.

One exit worth remembering: Uber leaves Zomato on Wednesday 3 August 2022. Uber had been paid in Zomato shares for Uber Eats India in 2020 (Why Does the Stock Market Exist? follows Zomato's road). Soon after its lock-in: show the note on Lock-in ended, the year after Zomato's listing in which early owners could not sell, it sold all of them on BSE: about 61.2 crore shares, 7.78% of the company, at ₹50.44 each, about ₹3088 crore (about $390 million), to more than a dozen funds and insurers. The price was about 9% below the previous close; Zomato's shares closed at ₹55.45 on NSE that day, almost where they started. Zomato itself received nothing: existing shares changed owners. Headlines called it a block deal, but it did not use a block window: its price was far outside the window's limit at the time, 1% from the reference, so it went through BSE's normal market that morning. At 7.78% of the company, far above the 0.5% line, it had to be disclosed, and the buyers' names and prices were published the same day.

NSE's 2026 list has 16 trading holidays on weekdays, Tuesday 20 October, Dussehra, among them. One, Thursday 15 January, a civic election day in Maharashtra, was added in January, after the list came out in December. Settlement keeps a separate list of its own, with a few extra days when the market trades but nothing settles (Clearing & T+1 Settlement).

Sessions can also be added by notice. For the Union Budget, NSE held live trading sessions on Saturday 1 February 2025 and Sunday 1 February 2026. Muhurat trading: show the note on Muhurat trading is a short special session on Diwali's Laxmi Pujan day, with its times set each year by circular. For Sunday 8 November 2026: the block window at 1:50 pm, the pre-open at 2:05, the normal market from 2:20, the closing auction from 3:15 to 3:35 pm for shares with futures and options, other shares to 3:30, and the post-close from 3:50 to 4:00 pm. NSE's circular says every trade in it is settled like any other.

Other markets, in India time. New York's NYSE trades from 9:30 am to 4:00 pm local time, opening and closing with auctions. India keeps one clock all year and the US does not, so in India time that is 8:00 pm to 2:30 am in the US winter (from Monday 2 November 2026) and 7:00 pm to 1:30 am in the US summer (from Monday 15 March 2027). Seen from New York, India's whole session runs overnight: 9:15 am in India is 10:45 pm the evening before in a New York winter. Many US brokers also offer extended-hours trading, typically 7:00 to 9:30 am and 4:00 to 8:00 pm New York time, with thinner trading and bigger price swings. Tokyo trades from 9:00 to 11:30 am and 12:30 to 3:30 pm, with a lunch break: 5:30 to 8:00 am and 9:00 am to noon in India, so its afternoon overlaps India's first three hours.

India's share market has no extended hours at new prices: outside its sessions you can only queue an order (chapter 6). India's commodity and currency segments keep hours of their own. A trade matched inside these hours is still not settled: when the shares are really yours is the next lesson.