Basic Concepts4 分钟阅读

Regular and After-Hours Trading Times

Have you ever tried to place an order during the day only to see "market closed," or seen U.S. stocks moving in the early morning? It's because each market has set opening and closing times.

Korea's Regular Session: 9:00 a.m. to 3:30 p.m.

The Korea Exchange (KRX) regular session (regular trading hours) is weekdays from 9:00 a.m. to 3:30 p.m. Only within these hours does the ordinary real-time trading we know take place.

Orders themselves (quote reception) start being accepted from 8:30 a.m., 30 minutes before the open. The market does not open on weekends and holidays.

Based on a regular session of 09:00–15:30 (quote reception from 08:30). (Source: Easy-to-Find Everyday Legal Information — trading hours)

Korea's After-Hours Trading

There are separate time slots called "after-hours trading" before and after the regular session. The trading method differs by type.

Pre-market closing-price session (08:30–08:40): you can buy and sell only at the previous day's closing price.

Post-market closing-price session (15:40–16:00): you trade only at that day's closing price.

After-hours single-price session (16:00–18:00): you can order at your desired price within ±10% of the day's closing price, with execution gathered once every 10 minutes.

The Korea Exchange is pursuing extended trading hours (an after-market, etc.), and the start date may be adjusted, so check your securities firm's notices before actually using it. (Source: KB's Thoughts — after-hours trading; bizwatch 2026-06-19)

The U.S. Regular Session: It Opens at Night

The regular session of the U.S. New York Stock Exchange (NYSE) and NASDAQ runs from 9:30 a.m. to 4:00 p.m. local time (U.S. Eastern Time, ET).

The issue is the time difference. Korea is far ahead of the U.S. East Coast, so the U.S. regular session, in our time, roughly runs from about 10:30 p.m. (during daylight saving time) to 5:00 a.m., and in winter from 11:30 p.m. to 6:00 a.m.

Because the U.S. observes daylight saving time from about March to November, the open time in Korean terms shifts by an hour depending on the season. This is why you have to stay up until dawn to watch U.S. stocks in real time.

The U.S. regular session is 09:30–16:00 ET. The Korean-converted time shifts by about an hour depending on daylight saving time. (Source: Charles Schwab; stockmarkethours.org)

U.S. After-Hours (Pre-Market and After-Hours)

The U.S. also has after-hours trading before and after the regular session. Before the regular session it's called the pre-market, and after it, after-hours.

Generally, the pre-market runs from 4:00 a.m. to 9:30 a.m. ET, and after-hours from 4:00 p.m. to 8:00 p.m. ET. However, the exact times and availability differ by securities firm and exchange.

After-hours trading is thin because there are few participants. The gap between the buying and selling prices (the bid-ask spread) widens, and the price can jump greatly even on small orders, so there's a risk of executing at a less favorable price than in the regular session.

The pre-market and after-hours have low liquidity and high volatility. Check the terms of use with each securities firm. (Source: Charles Schwab — Extended Hours Trading)

常见问题

Q. Is after-hours trading okay for beginners?

Because trading volume is low, you may not execute at your desired price or may be caught at a less favorable price than expected. In particular, U.S. after-hours prices swing greatly on news, so if you're not used to it, starting with regular-session trading is safer. For long-term investors, there is often no need to use after-hours at all.

Q. What is U.S. daylight saving time, and why should I care?

Daylight saving time is a system that moves the clock forward by an hour during the long-daylight season; the U.S. observes it roughly from mid-March to early November. During this period, the U.S. market opens an hour earlier in Korean terms. Mistaking the open time can cause you to miss your order timing, so if you watch U.S. stocks, it's worth knowing.