Recently, I saw quite a few discussions in investment communities. Some people borrow money to buy stocks and double their profits, while others blow up their accounts and go into debt. It's the same borrowing to invest, so why are the results so different? I took some time to organize a few thoughts.

Honestly, the essence of borrowing money to buy stocks is leverage. It’s neither good nor bad in itself; the key is how you use it. Many people lose money not because borrowing itself is bad, but because they don’t fully understand the true costs and risks behind it.

There are usually three layers of costs when borrowing to buy stocks. The first and most direct is interest. In Taiwan, brokerage financing rates are about 3%-6%. It doesn’t seem high, but over the long term, it will continuously eat into profits. I calculated an example: borrowing 1 million to trade stocks, with an annual interest rate of 4%, amounts to 40k in interest per year. If you only earn 50k in a year, after deducting interest, your actual profit is just 10k, cutting your profit rate by 80%. Even more absurd is that whether your stocks gain or lose, the interest must be paid on time. In a long-term sideways market, this becomes a situation where you only pay interest without making any money.

The second layer of cost is volatility and slippage. Both Taiwan stocks and US stocks are highly volatile, and borrowing to trade amplifies this volatility through leverage. The most dangerous is margin calls. For example, if you use 100k of your own funds plus 100k borrowed to buy stocks, totaling 200k with a 50% margin requirement. If the stock suddenly drops 20%, losing 40k, your own funds are left with 60k, and the margin ratio drops to 30%. Falling below the 50% requirement, the broker will force you to add funds. If you can’t, they will forcibly liquidate your position. This situation is especially common during sharp rises and falls in the US stock market or during volatile moves in TSMC ADRs.

The third layer, and also the easiest to overlook, is psychological cost. Borrowing to invest puts you in a constant state of tension and anxiety, making it hard to think calmly. Emotions then influence your decisions, leading to mistakes. I’ve heard of people who initially only lost 20k, but because they were afraid of a margin call, they panicked and closed their positions, ending up losing 50k. Others made 30k profit but, driven by greed and leverage, chased high and ended up losing everything, even turning a profit into a 40k loss. These are all psychological costs at play.

There are several ways to borrow money to buy stocks. The most traditional is brokerage margin financing, borrowing money or stocks from brokers to buy or short sell. The threshold is relatively high, usually requiring over 500k in funds and at least one year of trading experience, with interest rates of 3%-6%, plus transaction and custody fees. Then there’s bank personal loans, with interest rates typically between 8%-15%, requiring good credit records. Stock pledging involves using your holdings as collateral to banks or brokers to get cash, with interest rates of 6%-10%, suitable for those holding high-quality stocks long-term. Lastly, margin trading, which involves using a portion of your funds as collateral to open positions—such as futures or CFDs—offers the highest risk but also the greatest flexibility.

Compared to traditional brokerage margin financing, which has high thresholds, high costs, and many restrictions, margin trading platforms usually have lower entry barriers, more transparent costs, and only charge spreads or overnight interest, without additional account opening or custody fees. But regardless of which you choose, risk control is essential.

Key points for risk management include: first, calculating the true interest costs; your investment return must exceed the borrowing rate to be profitable. Second, control leverage ratios; it’s recommended that debt not exceed 50%. Third, keep emergency funds to handle unexpected situations; repaying principal and interest on time is crucial, or you risk penalties and credit damage. Fourth, set stop-loss points; sell immediately if the stock price hits a certain level to prevent larger losses. Fifth, most importantly, avoid emotional trading—every investment should have a clear plan, and strict discipline in execution.

In short, borrowing to buy stocks is never about how much money you borrow, but whether you can control the risks. Many people lose money because they only see leverage as a way to amplify gains, ignoring that it can equally magnify losses at the same speed. If you plan to borrow to invest, first understand these costs and risks thoroughly, then decide whether and how much leverage to use based on your risk tolerance and market judgment.