Recently, someone asked me why I always get confused about the differences between trading stocks in the Taiwan stock market and the U.S. stock market—especially the concepts of “one share” and “one lot.” To be honest, beginners who are just getting started in the stock market can easily be thrown off by these basic ideas at first, but in reality, they’re not that complicated to understand.

First, the most straightforward explanation: a stock price is the trading price of a stock, which tells you how much money you need to pay to buy one share. This price changes every day, depending entirely on real-time matching between buyers and sellers in the market. For example, the same stock might be 100 NT dollars today, and then become 105 NT dollars tomorrow—this is how it works.

As for how much one share costs, it essentially comes down to the current market price. Take TSMC as an example: suppose at a certain point TSMC’s stock price is over 560 New Taiwan Dollars—that means buying one share of TSMC would cost over 560. If you look at Tesla in the U.S. market, it might be around 250 USD per share. Par value doesn’t really matter; it’s only a record from the company’s history. What truly determines how much a stock is worth is whether the company itself can make profits, and what investors think about the company’s future prospects.

Now, let’s get to the most important difference. The Taiwan stock market has a unique trading unit called “one lot.” One lot equals 1,000 shares. That means when you buy one lot in the Taiwan market, you’re buying 1,000 shares at once. This is why many people think trading in Taiwan is so expensive—the minimum trading unit is simply too large. For example, if one share costs 560 NT dollars, buying one lot would require 560,000 NT dollars, which is indeed a big sum for retail investors.

In contrast, the U.S. stock market is much simpler: the trading unit is just one share, with no concept of “one lot.” Taking TSMC again, the U.S. version (ticker TSM) might be only 95 USD per share, which comes out to a little over 3,000 NT dollars after converting currency. This is why U.S. stocks seem so much cheaper—not because the stock itself is cheaper, but because the trading unit is smaller.

To lower the entry barrier for Taiwan stocks, the Taiwan market later introduced fractional share trading, which allows buying and selling less than one lot (from 1 to 999 shares). This way, ordinary retail investors can participate without needing to gather 560,000 to buy TSMC. Of course, the liquidity of fractional trading isn’t as good as trading whole lots, with matching occurring only once per minute, but at least it gives people with smaller budgets a chance.

The factors that affect the price of one share of stock can actually be grouped into three categories. First is the company’s fundamentals, including its financial condition and profitability. Companies with strong performance naturally attract buy orders, so their stock prices rise. Second is the macroeconomic environment—factors like GDP, interest rates, and exchange rates can all influence prices. Third is market sentiment. Sometimes, a bad piece of news or a political event can trigger panic selling.

In summary: to know how much one share costs, just look at the market price. To calculate how much one lot costs, multiply the per-share price by 1,000. The biggest difference between Taiwan stocks and U.S. stocks lies in this trading unit, and that’s also why the same stock can look so different in the two markets. Once you get these basic concepts straight, it becomes much easier to choose the market that fits you for trading.