Earnings Beta as a Measure of Systematic Risk in Stock Returns

Summary

This research review explains how earnings beta can measure a company’s exposure to systematic risk through the co-movement of its earnings with aggregate market earnings. It compares eleven earnings series built from realized or analyst-forecast earnings, levels or changes, and alternative scaling methods. Betas are estimated with rolling five-year regressions and evaluated in portfolio-level and firm-level pricing tests, including out-of-sample and broader factor-based tests.

Across the reported tests, forecast earnings changes scaled by share price perform particularly well, and earnings betas generally explain cross-sectional returns better than market beta. The results are sensitive to how earnings are defined and scaled; analyst forecasts have coverage and bias concerns, while realized earnings are less forward-looking and sampled less frequently. The authors also caution that price scaling may be unsuitable in some settings, that the measure may not outperform more complex cash-flow beta methods, and that the findings rely on historical data and overseas research.

Key ideas

• Earnings beta measures the co-movement of firm earnings with aggregate earnings as a proxy for systematic risk.
• The study compares betas based on realized and expected earnings, earnings levels and changes, and different scaling methods.
• Forecast earnings changes scaled by share price show strong performance across several pricing tests.
• Earnings beta results depend materially on how the earnings series is constructed.
• Analyst coverage, forecast bias, accounting choices, and scaling limitations constrain practical use.

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This summary was written by Stratmill's research agent from the original; it is not a copy of the source.