What Return on Equity Actually Measures

Return on equity, or ROE, cuts straight to a company's ability to turn shareholder money into profit. It is calculated as net income divided by shareholders' equity, expressed as a percentage. A 30% ROE means that every €10,000 invested by owners generates €3,000 in net earnings each year.

Because ROE isolates the efficiency of equity capital, it is a favourite measure among long-term investors. A high ROE signals strong capital allocation and a business with durable competitive advantages. However, the metric ignores debt entirely, so a company that borrows heavily can artificially inflate its ROE through financial leverage. That makes comparisons – against a firm's own history, the sector average, and the broader market – essential.

The Research Behind ROE's Market-Beating Record

A Consistent Outperformance Pattern Across Decades

Credit Suisse research covering 1965–2015 found that the top quintile of companies by ROE beat the bottom quintile by an average of 17% per year. Greenwald, Kahn, Sonkin and van Biema analyzed U.S. stocks from 1975 to 2009 and concluded that companies with high and stable ROE tended to outperform the market over the long run, while those with low and volatile ROE underperformed.

The same relationship appears globally. Studies on the Taiwanese, European, Indian and U.S. markets – from Hsu, Wu and Yeh (2014) to Chan and Zhang (2021) – all point in the same direction: stocks with the strongest return on equity have historically delivered excess returns. The logic is that high, sustainable ROE reflects a genuine economic moat that competitors struggle to erode.

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Why the Metric Alone Isn't Enough

ROE's biggest blind spot is debt. A company can juice its ROE simply by taking on more loans, because borrowed money boosts earnings without increasing equity. That is why any ROE screen must be paired with an analysis of the balance sheet. A 40% ROE that comes from a debt-to-equity ratio of 3.0 is far less impressive than a 25% ROE supported by minimal leverage.

Using ROE Screens Without Falling for the Leverage Trap

  • Pair ROE with a debt check. Before acting on a high ROE screen, look at the company's debt-to-equity ratio. If both measures are high, the apparent profitability may be a leverage illusion rather than operational strength.
  • Compare against historical ROE, not just the industry. A steady ROE of 18% over a full cycle is more meaningful than a one-year spike to 30%. Screen for consistency across at least five years.
  • Use ROE as a filter, not a standalone call. High ROE can shorten your watchlist, but final decisions still require looking at cash flows, management quality and the competitive landscape – none of which ROE captures.