07. Does high ROE mean a good business?

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High return on equity deserves investigation, but a small denominator or substantial leverage can raise it. Hanbit's first-year ROE is 52.9%. Decompose that number before assuming new investment can earn the same return. Amounts are KRW million.

Match a period's income with a capital base

Net income is 28.8, opening equity is 40, and closing equity is 68.8. Using the simple average of opening and closing equity gives 54.4, so ROE = 28.8 ÷ 54.4 = 52.9%. Using closing equity instead produces 41.9%. Comparing those two conventions as if they were identical can distort a ranking.

For a real company with a large midyear share issue or buyback, quarterly or more detailed average balances may be needed. Align earnings attribution with the equity measured. Our simplified company has only ordinary shareholders and no noncontrolling interests.

Decompose the result

Component	Calculation	Result
Net margin	28.8 ÷ 200	14.4%
Asset turnover	200 ÷ average assets 124.4	1.608 times
Equity multiplier	124.4 ÷ average equity 54.4	2.287 times

Multiplying the unrounded components returns 52.9%. This is an arithmetic identity: sales and average assets cancel between the fractions. It helps distinguish margins, sales generated per unit of assets, and the relationship between assets and equity. Measurement choices and leverage are central issues in interpreting accounting returns.¹

Hanbit began with debt of 60 on top of equity of 40. Its small initial equity base and startup financing affect the first-year result. One-off profit or shrinking equity can also raise ROE. If average equity is near zero or negative, inspect the underlying income and equity changes before using the ratio to rank companies.

ROIC asks a different question

ROIC generally compares after-tax operating profit with invested capital, considering business funding from creditors as well as shareholders. Treatment of excess cash, goodwill, leases, and taxes can change the result.¹ Establish those definitions before interpreting a high ROE as evidence of strong operating efficiency.

Rather than inventing a precise invested-capital allocation, consider an independent project: invest another 20 in equipment and working capital to obtain annual incremental after-tax operating profit of 2. Its simple incremental return is 10%, not the historical ROE of 52.9%. A complete decision would also consider the timing of investment, cash recovery, and project risk.

Keep a short record

When ROE rises, inspect margins, turnover, borrowing, and equity movements separately. Then ask what supports the return on the next unit of investment. Strong past returns, a growing market, and attractive reinvestment opportunities are three different claims. Separating them prepares you to ask whether the share price already assumes all three.