We develop a simple approach to valuing risky corporate debt that incorporates
both default and interest rate risk. We use this approach to derive simple closed-form
valuation expressions for fixed and floating rate debt. The model provides a number
of interesting new insights about pricing and hedging corporate debt securities. For
example, we find that the correlation between default risk and the interest rate has
a significant effect on the properties of the credit spread. Using Moody's corporate
bond yield data, we find that credit spreads are negatively related to interest rates
and that durations of risky bonds depend on the correlation with interest rates. This
empirical evidence is consistent with the implications of the valuation model.