I only just recently realized that the U.S. stock trading hours are more complicated than I thought. It’s not just one fixed time—it changes with daylight saving time and standard time. Now that it’s already the end of May and daylight saving time has started, if you’re in Taiwan watching U.S. stocks, the trading hours are from 9:30 PM to 4:00 AM the next day, which is one hour earlier than in winter.

Even more importantly, the U.S. stock market has a huge number of days when it’s closed. Just this year alone, there are more than a dozen holidays to pay attention to. For example, since Memorial Day has already passed on May 25, the upcoming holidays in June and July include Independence Day, which you should watch out for. Especially the week of July 4—because it falls on a Saturday, the market will close early on the preceding Friday. Also, around Thanksgiving and Christmas toward the end of the year, it’s not just that the markets are closed—on some days, trading also ends three hours early. This makes it very easy to get caught out if you’re trying to time your trades precisely.

In addition, unlike Taiwan’s stock market, which has only one exchange, the U.S. has three—New York, NASDAQ, and the American Stock Exchange—each operating independently. Although their opening hours are usually synchronized, the prices and trading volumes may differ. If you want to invest in U.S. stocks seriously, you really need to understand these details, especially the schedule for market holidays—otherwise, you could end up in an awkward situation where you want to trade but find that the market is closed.