2. The costs a headline expense ratio leaves out

Official sources checked September 6, 2026. Unnamed candidates and numerical illustrations are hypothetical.

Fund A charges 0.05 percentage points less per year than Fund B. On KRW 10 million, the simple annual difference is KRW 5,000. But what if trading A costs several times that amount through the spread? A lower published fee does not finish the calculation.

Separate expenses deducted within the fund from costs incurred when you trade. The SEC’s fee bulletin explains that an expense ratio does not capture every cost, including brokerage charges.¹

Keep the expense schedule separate from the performance record

Read the definitions attached to each fee figure. For a Korean fund, look beyond total remuneration to other expenses and securities trading commissions. A historical operating-cost figure and a newly announced fee rate describe different things. Record the reporting period and effective date.²

Next examine implementation results. Here, tracking difference means the fund’s NAV total return minus its benchmark’s total return over the same period. Tracking error concerns the variability of return differences. Check the provider’s observation frequency and annualization method before comparing published statistics.³

Suppose the benchmark returned 10.0% and the ETF returned 9.7% after fund expenses. The tracking difference is -0.3 percentage points. Fees, cash balances, execution timing and taxes may all contribute. Subtracting a 0.1% management fee again to report a 9.6% return would count an embedded expense twice.

Use the expense schedule to investigate causes and the performance record to observe outcomes. Adding them together indiscriminately is misleading. One year’s result also does not establish a permanent ranking.

One order can create a measurable gap

Assume the ask is KRW 10,020 and the bid KRW 9,980 at the same instant. Buying 100 shares and immediately selling them at those unchanged quotes loses KRW 4,000. The full spread is 0.4% of the KRW 10,000 midpoint. Because this describes a round trip, do not assign the entire 0.4% to both the purchase and the sale.⁴

Relative to the KRW 1,002,000 purchase outlay, the loss is about 0.399%. Actual commissions and currency-conversion charges would be additional. An order larger than the displayed quantity may also execute at multiple prices.

Your holding period belongs in the calculation

A 0.05 percentage-point saving on KRW 10 million equals KRW 5,000 per year in a simple constant-balance model. If switching costs KRW 20,000, recovering that expense takes four years. This deliberately excludes taxes, price changes and compounding, but it is a useful first question before switching because of a fee announcement.

Add an expected holding period and a switching-cost estimate to the worksheet. Then consider whether the likely saving also justifies the work of repeatedly moving to the newest low-fee product.

Continue the series

1. Are ETFs tracking the same index really the same?
2. The costs a headline expense ratio leaves out
3. Does a larger distribution mean a better investment?
4. Does currency matter when you buy an overseas ETF in won?
5. What changes across a regular account, ISA and pension account?
6. Finish an ETF comparison sheet for your own purpose

Footnotes

1. SEC · Investor.gov, Mutual Fund and ETF Fees and Expenses. Accessed September 6, 2026. ↩

2. 삼성자산운용 · Samsung Asset Management, 중개형 ISA 투자 가이드. Accessed September 6, 2026. ↩

3. 한국거래소 · Korea Exchange, ETP 종목정보 및 지표 설명. Accessed September 6, 2026. ↩

4. SEC · Investor.gov, Updated Investor Bulletin: Exchange-Traded Funds (ETFs). Accessed September 6, 2026. ↩