After-hours trading explained: why the price after the bell isn't the close

Intel's third-quarter results reached the SEC's EDGAR system at 16:08:53 New York time on 29 October 2026, about nine minutes after the regular session closed, according to the filing index. Anyone who wanted to trade on the news that evening, or before 9:30 a.m. the next day, had to use extended-hours trading: the pre-market and after-hours sessions that run either side of the main trading day. Prices quoted from those sessions are real trades, but they are set under different conditions, and they are not the official close.

For US exchange-listed stocks, the regular session is 9:30 a.m.-4:00 p.m. Eastern Time (ET), and anything outside that window is extended-hours trading, says an SEC investor bulletin of 6 June 2022. How long those sessions last depends on the venue. On the Nasdaq Stock Market, pre-market trading starts at 4:00 a.m. and after-hours trading ends at 8:00 p.m. ET, Nasdaq's trading-hours page says, adding that some brokers set different windows. FINRA, the US brokerage industry's self-regulator, describes 7:00-9:30 a.m. as the typical pre-market window in its investor guide of 31 July 2024, and notes that overnight trading between 8 p.m. and 4 a.m. ET has more recently been opened to retail investors in certain stocks.

Extended-hours trades can happen on exchanges, on alternative trading systems (ATSs), which are private venues operated by broker-dealers, or at other trading centres, and not every market that is open during the day is open outside it, according to Investor.gov. Which orders are accepted and which securities can be traded may also differ from the regular session.

FINRA's model risk statement under Rule 2265 says issuers normally make announcements that may affect their share price after regular hours. Nasdaq runs a notice-and-halt process for such news, described on its MarketWatch page. According to that page, Nasdaq-listed companies must tell MarketWatch, the Nasdaq team that reviews material news, at least ten minutes before releasing certain material news between 7:00 a.m. and 8:00 p.m. ET, and before 6:50 a.m. ET for releases outside that window. MarketWatch can impose a temporary trading halt so the news reaches everyone at once; it considers halts in the pre-market and after-hours sessions as well as in regular hours, and trading normally restarts about 30 minutes after the news is out.

Fewer buyers and sellers are active outside regular hours, so prices can swing more, quotes can be wide or missing, and some stocks may not trade at all, Investor.gov warns. Extended-hours systems are not linked, so the same stock can show different prices on different venues at the same moment, the bulletin adds. During regular hours, SEC rules generally require brokers to fill customer orders in listed stocks at the National Best Bid and Offer (NBBO), the best price available across markets. Because the NBBO is published only in regular hours, that requirement does not apply in extended trading, FINRA explains.

The official closing price is the one recorded at 4:00 p.m., whatever happens later, and investment funds use it to value their holdings, according to FINRA. The next morning's opening price is set by supply and demand around the open, and because pricing then may differ from the extended-hours session, a price paid after hours can turn out worse than one in the following regular session, FINRA notes. FINRA's own example is a company whose earnings disappoint once the market has shut: its shares may drop fast after hours, yet trading may calm once investors have digested the results and the regular session resumes.

FINRA Rule 2265 bars a broker from letting a customer trade in extended hours until it has given that customer a risk statement, on paper or electronically, and brokers that offer such trading online must also post the statement prominently on their website. Many brokers accept only limit orders in these sessions, which fill only at the chosen price or better, and investors should check whether unfilled orders are cancelled or carried into the next session, Investor.gov says. It adds that many extended-hours traders are professionals who generally have access to more information than individuals do.

FINRA's 2026 oversight report lists findings at firms that include weak supervision of potentially manipulative after-hours activity and failures to report extended-hours trades to its Trade Reporting Facilities or the Consolidated Audit Trail (CAT). It suggests firms' supervision take account of overnight price bands.

Nasdaq says it plans to trade US equities 23 hours a day across the five-day trading week, starting on Sunday 6 December 2026 at 9:00 p.m. ET. Each week would run from Sunday evening to 8:00 p.m. on Friday, with a one-hour pause from 8:00 to 9:00 p.m. each weekday for maintenance and some corporate-action processing, and with US market holidays still observed, according to its 23 October explainer. The plan keeps the Opening and Closing Crosses, the auctions at the start and end of the regular session, and the Closing Cross still sets the official close for Nasdaq-listed stocks. Nasdaq expects most liquidity to stay in traditional US hours, and says the regulatory proposals are still going through approval.

The SEC's order of 10 April 2026 (Release 34-105199) granted accelerated approval to Nasdaq's rule framework: a Day Session, 4:00 a.m.-8:00 p.m. ET, covering today's pre-market, regular and post-market hours, and a Night Session, 9:00 p.m.-4:00 a.m. ET. It did not switch the Night Session on. Nasdaq must first file a further rule change confirming that the Equity Data Plans, which oversee the securities information processors (SIPs) that consolidate quotes and trades, are ready for night hours. If that filing is not made within 18 months of approval, Nasdaq is to file promptly to remove the Night Session rules, the order says.

NYSE Arca plans a new Overnight Session from 9:00 p.m. to 4:00 a.m. ET, starting Sunday to Thursday evenings, while its Early, Core and Late sessions keep their times; the plan is for the other NYSE Group equity exchanges to keep their current hours, NYSE's extended-hours FAQ of August 2026 says. It puts the launch on 6 December 2026, subject to SEC approvals, the SIPs being available and DTCC's modernisation work. Only US broker-dealers that are NYSE Arca members can trade directly in the new hours.

On NYSE Arca, the Overnight Session would open with continuous trading rather than an auction, trades between 9:00 p.m. and midnight would take the next calendar day's trade date, and the Limit Up/Limit Down plan, which stops trades outside set price bands, now has static 20% overnight price bands, according to the FAQ.

NYSE Arca will still publish its official closing price after the 4:00 p.m. Core Closing Auction, and trades in the Overnight, Early and Late sessions count toward consolidated volume, the FAQ says. NYSE Arca's rule filing SR-NYSEARCA-2026-97, made on 14 September and published by the SEC on 18 September 2026, states that the SEC approved Arca's 23/5 proposal in May 2026 and that 23/5 trading is scheduled to begin across the industry on 6 December 2026.

In its filing, as summarised in the SEC order, Nasdaq said extended-hours volume "tends to be considerably lower" than in regular hours, but that interest in overnight trading is growing, especially among investors in Asia and other places whose business hours do not match US hours. One comment letter warned of potential risks from round-the-clock trading, including thin markets, sharp swings, gamification and harm to small investors, and another commenter said hours without trading give markets a "vital cooling-off period" to absorb news. Nasdaq replied that the SEC had already weighed such concerns when approving similar proposals from other exchanges.

The Tokyo Stock Exchange trades domestic stocks from 9:00 to 11:30 a.m. and from 12:30 to 3:30 p.m. Japan time, accepting orders from 8:00 a.m. and 12:05 p.m., according to the exchange's trading-hours page. On 5 November 2024 it lengthened the trading day by 30 minutes and added a closing auction at the end of the afternoon session, TSE announced on the site of its parent, Japan Exchange Group (JPX). US daylight saving time ended at 2 a.m. local time on 1 November 2026, according to NIST. US session times in ET stay the same, but by Polstob's arithmetic the 9:30 a.m. ET open is 14:30 UTC from 2 November, an hour later than in summer.