Book Values and Market Values of Equity and Debt

This paper propses a contingent claims model to value a firm's debt and equity as functions of observable book values appearing in published financial statements. Equity fair value critically depends on expected earnings, equity book value and earnings volatility, because of the options to default or to voluntarily liquidate the firms. Debt value increases in earnings volability in the proximity of default. Default is triggered by the erosion of equity due to negative earnings. Debt and equity values are materially affected by the strength of the mean reversion of profitability. Voluntary liquidation before default may be optimal and it entails that a sudden sharp decline in profitability can be less detrimental to creditors than a slower but persistent one.