Recently, I was chatting with a few investment friends and found that many people are still a bit confused about pre-market trading in U.S. stocks. So I’ll organize my understanding here to see if I can help everyone clarify their thinking.

Pre-market trading in U.S. stocks actually refers to the buying and selling of stocks during the period before the official market open. The New York Stock Exchange and NASDAQ usually start accepting pre-market trades from 4 a.m. Eastern Time until the official opening at 9:30 a.m. This period doesn’t seem long, but for many traders, it’s a golden time. Why? Because the global market activities overnight, unexpected international news, and company announcements are all concentrated and reflected during pre-market hours.

I think the biggest significance of pre-market trading is that it gives investors a chance to get a head start. Imagine a listed company releases important earnings reports or restructuring announcements after the U.S. stock market closes; other investors have to wait until the next day’s open to react, but those participating in pre-market trading can adjust their positions in advance. That’s why pre-market prices sometimes fluctuate so dramatically—everyone is racing to gain an informational advantage.

However, pre-market trading also has obvious limitations. First, you can only place limit orders, not market orders. This is because the number of participants is relatively small during pre-market hours, and liquidity is insufficient; using a market order could lead to getting trapped. Second, not all brokers support pre-market trading. Among the brokers I’ve used before, some only support pre-market from 7 a.m. ET, while others start as early as 4 a.m. It’s quite a significant difference.

I remember a few years ago when Alibaba experienced a big pre-market plunge. At that time, the founder’s share reduction plan was exposed, along with the suspension of a subsidiary’s IPO, and the stock dropped more than 8 percentage points before the open. This clearly shows how much pre-market trading can influence the opening price. Sometimes, the pre-market trend essentially determines the day’s opening momentum.

After discussing pre-market, let’s talk about after-hours trading. Simply put, after-hours trading is trading that continues after the market closes. After the U.S. market closes at 4 p.m. ET, investors can still trade on brokerage platforms, usually until around 8 p.m. The common point between after-hours and pre-market trading is that both have low liquidity and high volatility, and only limit orders can be used. The difference is that after-hours trading generally involves less new information, so prices tend to be more stable and can more accurately reflect the market’s rational valuation.

If you want to trade during the pre-market hours, my advice is to keep a close eye on news. Earnings seasons, major mergers and acquisitions, regulatory developments—these often trigger big swings during pre-market. Also, setting buy prices lower than your ideal price or higher than your target sell price is a good strategy, because pre-market quotes can sometimes be extreme.

From a risk management perspective, I recommend avoiding large trades during pre-market hours, as the risk of not being able to execute is high. Also, stay alert to sudden news events, since pre-market is most vulnerable to black swan events. Most importantly, set stop-loss orders to prevent a single pre-market mistake from damaging your account significantly.

If the liquidity issues in U.S. pre-market trading seem too troublesome, there are other options. For example, trading Contracts for Difference (CFDs)—these products are not limited by exchange hours and can be traded almost 24/7. Many reputable platforms offer U.S. stock CFDs, with relatively low minimum investments, making them friendly for small investors.

In summary, pre-market trading in U.S. stocks indeed offers opportunities, but it also carries higher risks. The key is to understand its mechanism, do your homework, and implement proper risk management measures. Don’t be scared by pre-market volatility, nor let potential gains cloud your judgment—rational trading is the long-term way to make money.