Recently, many beginners have been asking about the concepts of limit-up and limit-down boards, so I decided to organize some knowledge points on this topic. To be honest, understanding these two concepts is not difficult, but many people still tend to make mistakes when trading.

First, let's define them. A limit-up board is when the stock price rises to the maximum allowed increase, and the price is frozen there, unable to go higher. Conversely, a limit-down board is when the stock price drops to the maximum allowed decrease and is frozen. Taking the Taiwan stock market as an example, the daily price change limit is 10%. If a stock closed at 600 yuan yesterday, then the highest price today would be 660 yuan (limit-up price), and the lowest would be 540 yuan (limit-down price).

How to determine if a stock is at limit-up or limit-down? The most straightforward way is to look at the candlestick chart. A limit-up stock will show a straight line upward, usually marked with a red background in Taiwan stock software. A limit-down is also a straight line, typically marked with a green background. Another signal is to look at the order book: at limit-up, buy orders pile up heavily, while sell orders are almost nonexistent, indicating far more buyers than sellers. For limit-down, the opposite applies.

Now, returning to a question many people care about: Can you buy or sell during a limit-up or limit-down? The answer is yes, trading is still possible; a limit-up does not prevent transactions—you can still place orders. But there's a trap—when placing a buy order, it may not be executed because a large number of buy orders are already queued at the limit-up price. Sell orders, on the other hand, will be executed immediately because many want to buy. For limit-down, the logic is reversed: buy orders are executed instantly, but sell orders may not be.

Speaking of this, I need to mention the differences between markets. Hong Kong and U.S. stocks do not have limit-up or limit-down restrictions; instead, they use circuit breakers. The U.S. market is more complex, with circuit breakers for the overall market and individual stocks. A market circuit breaker pauses trading for 15 minutes when the S&P 500 drops 7% or 13%, and halts trading entirely if it drops 20%. For individual stocks, circuit breakers are triggered if a stock's price moves more than a certain percentage (e.g., over 5% within 15 seconds), temporarily suspending trading for a few minutes.

When encountering a limit-up or limit-down situation, beginners often make the mistake of blindly chasing the market or panic selling. My advice is to analyze the underlying reasons first. For example, if a stock hits the limit-down but the company's fundamentals are solid and only market sentiment caused the drop, this could be an opportunity—consider small-scale buying or holding. Conversely, if a limit-up is driven by real positive news, assess whether that news can sustain the upward momentum; if not, it might be safer to wait and see.

If you really want to buy during a limit-up, there are other methods. One idea is to buy related stocks; for example, if TSMC hits the limit-up, other semiconductor leaders often follow suit. Another option is to use derivatives or Contracts for Difference (CFDs), which are not subject to limit-up restrictions, have relatively low entry barriers, and are especially suitable for small investors. CFDs can be traded 24/7, with flexible leverage, and allow both long and short positions, providing opportunities to profit from both rising and falling markets.

In summary: limit-up boards are a market stability mechanism, with Taiwan stocks limited to 10%, and Hong Kong and U.S. markets replacing this with circuit breakers. Orders can be placed during limit-up or limit-down, but they may not always be executed. If you are particularly eager to trade, consider related stocks or derivatives like CFDs, but be aware that these tools carry risks. Beginners should first understand the rules thoroughly before getting started.