These days, many people focus only on their returns when trading stocks, but they often overlook how much fees actually impact their final profit. Recently, I took a deeper look into comparing brokerage fees, and I realized the differences are much larger than I expected.

First of all, the fee structures are completely different when trading domestic stocks versus overseas stocks. Domestic stock trading combines brokerage commission fees and exchange-related agency fees, whereas overseas stock trading adds currency exchange fees, making it much more complicated. Especially when trading U.S. stocks, SEC fees and FINRA fees are also added, making it significantly more expensive than domestic trading.

When comparing the brokerage fees of the top five securities firms, the differences are really stark. Mirae Asset Securities charges about 0.136% for domestic stocks, Korea Investment & Securities and Samsung Securities around 0.147%, but Kiwoom Securities’ Hero Moon 4 platform lowers it to as low as 0.015%. Shinhan Investment Corp. charges a fixed 2,000 won plus 0.139% for trades under 30 million won. For overseas stocks, most fees are around 0.25%, but for domestic stocks, the trading amount and platform can cause huge variations.

Fixed fees can also be a headache. Fixed commissions like 1,500 won at Samsung Securities or 2,000 won at Shinhan Investment are really problematic for small, quick trades. For example, making 100 trades would cost 150k to 200k won just in fixed fees, which can seriously eat into your profits.

The power of compound interest shouldn’t be ignored either. Suppose you start with 1 million won and make 10 trades, each with a 10% return. The difference between a 0.1% and 0.2% fee can amount to 20,000 to 30k won in the end. As trading volume and frequency increase, this difference grows exponentially.

Therefore, when comparing brokerage fees, it’s crucial to check a few things. First, accurately identify your typical trading amount and platform, then choose the broker that offers the lowest fees under those conditions. If you mainly do small, quick trades, look for brokers without fixed fees; if you trade large amounts, pick one where the fee rate decreases as your trading volume increases.

Another important factor is fee promotion events. Most brokerages offer fee waivers for 3 months to a year for new or dormant accounts. Shinhan Investment, for example, waives U.S. stock trading fees for new non-face-to-face accounts for a year. Taking full advantage of these benefits can save you a lot of initial costs. Many brokers also let you choose when to start these promotions, so applying just before you begin active trading is a smart move.

When trading overseas stocks, you also need to pay attention to currency exchange fees. Often, the exchange rates offered by brokerages are worse than those at banks or specialized currency platforms. It’s wise to exchange dollars when rates are favorable or check if your broker offers preferential exchange rates.

Ultimately, comparing brokerage fees isn’t just about crunching numbers; it’s about choosing a strategy that fits your trading pattern. Even within the same broker, the actual fees you pay can vary greatly depending on your trading volume and frequency. Doing a proper calculation before starting can lead to significant long-term profit differences.