The Abnormal Earnings Formula

Last updated: May 2026 | Reading time: 8 minutes

Introduction to the Abnormal Earnings Model

The Abnormal Earnings model, also widely known as the Residual Income Valuation model or the Edwards-Bell-Ohlson (EBO) model, is a cornerstone of modern equity valuation theory. Unlike traditional discounted cash flow approaches that focus exclusively on future cash flows, the Abnormal Earnings model explicitly incorporates the book value of equity as a foundation and then adds the present value of expected future abnormal earnings.

This approach has gained significant traction among financial analysts, academics, and valuation professionals because it directly links a company's accounting performance to its market value. The model was formalized by James Ohlson in his seminal 1995 paper "Earnings, Book Values, and Dividends in Equity Valuation," building upon earlier work by Edwards and Bell (1961) and Peasnell (1982).

The Theoretical Foundation

The Abnormal Earnings model rests on a fundamental insight: a firm creates value for its shareholders only when it earns a return on equity that exceeds the cost of that equity capital. If a company earns exactly its cost of equity, it is merely maintaining the status quo — no value is created or destroyed. The model captures this intuition by decomposing the firm's value into two distinct components: the capital already invested (book value) and the present value of future economic profits (residual income).

The model is derived from the dividend discount model (DDM) under the assumption of clean surplus accounting, which states that all changes in book value pass through the income statement. This relationship, known as the Clean Surplus Relation, is expressed as Bₜ = Bₜ₋₁ + NIₜ − Dₜ, where Bₜ is book value at time t, NIₜ is net income, and Dₜ is dividends.

Key Components of the Formula

Derivation of the Abnormal Earnings Formula

The derivation begins with the Dividend Discount Model, which states that the value of equity equals the present value of expected future dividends:

V₀ = Σ Dₜ / (1+r)ᵗ

Using the Clean Surplus Relation (Bₜ = Bₜ₋₁ + NIₜ − Dₜ), we can solve for dividends as Dₜ = NIₜ + Bₜ₋₁ − Bₜ. Substituting this into the DDM and rearranging yields:

V₀ = B₀ + Σ (NIₜ − r × Bₜ₋₁) / (1+r)ᵗ

This elegant derivation shows that the Abnormal Earnings model is mathematically equivalent to the Dividend Discount Model under clean surplus accounting, yet it offers several practical advantages for valuation.

Practical Application

In practice, applying the Abnormal Earnings model involves the following steps:

• Step 1: Obtain the current book value of equity (B₀) from the most recent balance sheet.
• Step 2: Estimate the cost of equity (r) using CAPM or other asset pricing models.
• Step 3: Forecast future net income and book values for an explicit forecast period (typically 5-10 years).
• Step 4: Calculate residual income for each forecast period as RIₜ = NIₜ − r × Bₜ₋₁.
• Step 5: Discount each residual income amount back to the present using the cost of equity.
• Step 6: Estimate a terminal value for residual income beyond the explicit forecast period, often assuming residual income decays to zero or remains constant.
• Step 7: Sum the current book value, the present value of forecasted residual income, and the present value of the terminal value.

Advantages and Limitations

Advantages

• Accounting-based anchor: The model starts with book value, which is a known quantity, reducing reliance on speculative long-term forecasts.
• Earlier recognition of value: Value creation is captured earlier compared to DCF because the model recognizes the contribution of existing assets through book value.
• Useful for financial firms: The model works particularly well for banks, insurance companies, and other financial institutions where book value is a meaningful measure of value.
• Less terminal value sensitivity: The terminal value typically represents a smaller portion of total value compared to DCF, reducing valuation uncertainty.

Limitations

• Accounting quality dependence: The model relies on accounting numbers, which can be distorted by accounting policies, estimation errors, or earnings management.
• Clean surplus assumption: The model requires clean surplus accounting, which may not hold perfectly in practice due to items like other comprehensive income.
• Forecast horizon: The model requires explicit forecasts of net income and book value, which can be challenging for firms with volatile earnings.

Empirical Evidence

Academic research has consistently shown that the Abnormal Earnings model performs well empirically. Studies have found that the model explains a high proportion of the cross-sectional variation in stock prices, often outperforming traditional DCF and price-multiple approaches. Research by Frankel and Lee (1998) demonstrated that the model has significant predictive power for future stock returns, and subsequent studies have confirmed these findings across different markets and time periods.

Conclusion

The Abnormal Earnings formula is a powerful and theoretically rigorous approach to equity valuation. By combining the familiar concepts of book value and accounting earnings with the time value of money, it provides a practical framework that bridges the gap between accounting and finance. Whether you are a professional analyst, a portfolio manager, or a student of finance, mastering this model will deepen your understanding of what drives firm value.

For a more detailed exploration of the Abnormal Earnings Growth model and its applications, visit the Financial Wiki guide.