Regular market hours trading sessions Extended hours trading sessions
Time Orders can be placed at any time and will only be valid from 9:30 a.m. to 4:00 p.m. U.S. ET.
Orders in extended hours sessions can be placed outside of regular exchange market hours (9:30 a.m. to 4:00 p.m. U.S. ET) and are eligible for execution for the following times:

For orders placed on Schwab.com, Schwab Mobile, and thinkorswim platforms:

Pre-market: Orders placed between 8:05 p.m. (previous trading day) and 9:25 a.m. U.S. ET will be eligible for execution between 7:00 a.m. and 9:25 a.m. U.S. ET.

After hours: Orders placed between 4:05 p.m. and 8:00 p.m. U.S. ET will be eligible for execution during that time period.

Extended hours (13-hour continuous†): Orders placed anytime will be eligible for execution between 7:00 a.m. and 8:00 p.m. U.S. ET exclusively on thinkorswim.

For orders placed on thinkorswim platforms:

Extended + overnight (24-hour continuous†): Orders placed anytime will be eligible for execution 24 hours a day, each market day. Unless GTC is selected, orders expire at 8:00 p.m. U.S. ET each day.

† Except for 5-minute closures that occur before and after regular exchange hours.
Trading venues Trading occurs on exchanges like the New York Stock Exchange (NYSE) and Nasdaq and through a variety of venues, including market makers and other market centers. Similar to regular market sessions, trading occurs on exchanges like the New York Stock Exchange and Nasdaq and through a variety of venues, including market makers and other market centers.
Order types Many order types and conditions are accepted, including: market, limit, stop-limit, all-or-none, etc. Only limit orders are accepted.
Time in force Different timing choices are available, including Day, GTC, IOC, and FOK.
Different timing choices are available depending on the extended hours session and platform used:

For Schwab.com and Schwab Mobile:

Extended-hours a.m.: Pre-market Day order 
Extended-hours p.m.: After-hours Day order
Extended Hours: 13-hour Day or GTC order (Day orders expire at 8:00 p.m. U.S. ET each day.)

For thinkorswim platforms:

EXT AM: Pre-market Day order 
EXT PM: After-hours Day order
EXT 13h: 13-hour continuous Day or GTC order (Day orders expire at 8:00 p.m. U.S. ET each day.)
EXTO 24h: 24-hour continuous Day or GTC order (Day orders expire at 8:00 p.m. U.S. ET each day.)
Liquidity In general, higher-volume trading activity means more liquidity and a greater likelihood of order execution. Lower volume trading activity may result in lower likelihood of order execution, wider spreads, and greater price fluctuation.
Quotes The quotes you receive are consolidated and represent the best available prices across all trading venues.
Quotes and fills are not consolidated and represent the current prices available through the market. As a participant in the extended hours trading network, the market may also offer access to prices available in other participating markets but not necessarily all venues open for extended hours trading. Best execution is not guaranteed.

On thinkorswim platforms, mark, bid, ask, size, and level-2 quotes are shown. For EXTO (extended hours + overnight) orders, the last trade price is not displayed.