Lately, when I see people investing in stocks, they tend to focus only on their returns—but honestly, do you know that stock commissions can have an enormous impact on your final profits?

I’ve calculated this recently, and I think that for people who trade frequently, their annual returns can easily be reduced by 2–3% just because of commissions alone. And if your style is making frequent trades with small amounts, it’s even worse.

Do you know that stock commissions really differ from one securities firm to another? For example, Mirae Asset Securities charges about 0.136% for domestic stocks, while Korea Investment & Securities is around 0.147%, but on Kiwoom Securities’ Hero MUNU4 it drops as low as 0.015%. That means that even for the same type of trade, commissions can differ by more than 10 times depending on the securities firm.

Overseas stocks are a bit different. If we look at U.S. stocks, most securities firms charge around 0.25%, and on top of that, you also get charged currency exchange fees. If you exchange when the exchange rate isn’t favorable, the losses can be much larger than you’d expect.

What’s interesting is the fixed fee portion. Shinhan Investment Securities charges 0.1391639% + 2,000 won for trades of up to 30 million won. You might think, “What is 2,000 won even for?” But if you trade 100 times, that adds up to 200,000 won. If you mainly do small scalping trades, this can seriously eat into your profits.

So, I think like this. First, you should choose a securities firm that fits your trading style. If you trade small amounts frequently, choose one that has no fixed fees. If you trade large amounts all at once, choose one with a better commission tier.

Second, make good use of new customer events. Shinhan Investment Securities offers new customers one year of free U.S. stock commissions, while other securities firms may offer something like 3 months free. If you concentrate your trading during that period, you can significantly cut your stock commission costs.

Third, manage your trading frequency. If you don’t plan to buy in splits, it’s better to trade all at once. When the number of trades decreases, your commissions decrease too.

Fourth, when trading overseas stocks, check the currency exchange fees and the exchange rate. Securities firms’ exchange services are often less favorable than banks or currency exchange platforms.

Lastly, I want to add one more thing: you should also consider trading platforms these days. With low fees and tight spreads, you can trade more efficiently.

Stock commissions may seem small, but in the long run they make a massive difference. Thanks to the compounding effect, even a 0.1% difference can turn into a substantial gap in profits after several years. That’s why it’s important to analyze your trading patterns and choose the most efficient securities firm.