After-Hours Trading: What It Is, How It Works

After-hours trading is the buying and selling of stocks outside regular market hours (9:30 a.m. to 4 p.m. ET) and is part of the practice of extended-hours trading. The extended-hours market technically runs from Sunday at 8 p.m. ET through Friday at 8 p.m. ET.

Trading activity doesn't stop with the closing bell. Nearly every day, stocks make notable pre- or post-market moves in response to an earnings announcement or other market-moving news.

Extended-hours trading is bookended by two sessions: pre-market activity before the open and post-market activity after the close. On thinkorswim^® platforms, select securities can also be traded overnight 24 hours per day, five days per week (24/5).
 

Trading outside regular hours is no longer a niche activity. In 2019, it accounted for about 5% of all U.S. equity share volume. By early 2025, per the New York Stock Exchange (NYSE), that share volume had more than doubled to over 11%, with more than 1.7 billion shares trading outside regular market hours each day.

Retail investors can participate in after-hours trading, but it's important to understand the guidelines, guardrails, and risks involved.

The pre-market session occurs before the market opens at 9:30 a.m. ET. At Schwab, clients can place orders as early as 8:05 p.m. the previous evening; those orders become eligible for execution between 7 a.m. and 9:25 a.m. ET on Schwab.com or Schwab Mobile. On thinkorswim, eligible securities can be traded around the clock (24/5) by choosing an EXTO order type.

Demand for pre-market trading has grown exponentially in recent years. Market-wide, volume has increased roughly 15-fold since 2019, compared to about 2.3-fold for after-hours activity. Early morning trading now accounts for more than 55% of all extended-hours volume, per the NYSE.

After-hours trading occurs after the markets close at 4 p.m. ET. Schwab clients can trade after hours from 4:05 p.m. to 8 p.m. ET on Schwab.com or Schwab Mobile, or around the clock (24/5) on thinkorswim by selecting a GTC (EXTO 24h) order type (see table for details).

Although after-hours action made up about 83% of all extended-hours trading in 2019, its share volume has since fallen to roughly 45% as pre-market activity has surged. The total number of shares traded after hours has continued to grow, however, as extended-hours trading overall gains in popularity.

Extended-hours trading is made possible by electronic markets, which are computerized services that match buy and sell orders. For example, if a trader places an order to buy 200 ZYX shares at $45, the system looks for an order to sell at least 200 ZYX shares at $45. If there is, the trade is executed; if not, the order won't be filled.

While commissions and settlement times during extended-hours trading are the same as those in the regular session, there are several differences to consider. Most notably, only limit orders are accepted. Other order types, such as market, stop, and stop-limit orders—and orders with special conditions like fill-or-kill, immediate-or-cancel, or all-or-none—can't be placed.

After-hours orders are good only for the session in which they're placed and don't carry over into future sessions. The exception to this is a good 'til canceled (GTC) order that includes extended hours. On Schwab.com and Schwab Mobile platforms, the order type appears as GTC + extended hours, and on thinkorswim, it is styled as GTC (EXT 13h). These orders remain active across the pre-market, regular, and after-hours sessions for up to 180 calendar days, or until they're filled or canceled.

Using a GTC + extended hours order may potentially give traders the opportunity to enter or exit a trade at their desired price, but it can also result in multiple executions to fill a single order, especially if the security is thinly traded.

There are two primary benefits of extended-hours trading:

• Convenience: Some traders' schedules don't allow them to place trades during the regular session. Extended-hours sessions allow them to review the latest news and quotes and potentially place trades at a more convenient time.
• Ability to react to news: Many companies release earnings after the close of the regular session. After-hours traders can respond right away by adjusting positions and potentially participating in price swings, rather than waiting for the next day's open.

While trading outside regular trading hours can have advantages, there are also unique risks:

• Uncertain prices: In the regular session, stock quotes are consolidated and represent the best available prices across all trading venues. In extended hours, prices may come from only one venue and may not reflect prices shown in other electronic trading systems.
• Lower liquidity: Because fewer shares generally trade after hours, there can be wide spreads between the bid (the highest price a buyer will pay) and the ask (the lowest price a seller will accept).
• Greater volatility: With fewer participants trading, a single order can move a security's price more than it might during regular hours, leading to sharper swings.
• Partial fills: A limit order may fill only in part (or not at all) before the session ends.
• No index value calculation: Index levels generally aren't calculated or disseminated after hours, which can pose a challenge for traders of index-tracking products. Professional traders may gain an edge here by using proprietary systems that quickly estimate index values based on individual stock prices.

Trading before and after the regular session—through pre-market and after-hours functions on any Schwab platform and 24/5 overnight trading on thinkorswim—gives investors more ways to manage positions and react to news. But the trade-offs are notable: Only limit orders are accepted, liquidity will generally be thinner while spreads may be wider, and volatility may be more pronounced. Understanding the guardrails can help traders determine whether trading outside regularly scheduled market hours is a smart addition to their regular strategy.