approach allows us to relax the assumption of strict absolute priority which
underlies the traditional approach to valuing risky debt.
A number of important insights about the valuation of risky debt emerge
from this analysis. We show that the correlation of a firm's assets with
changes in the level of the interest rate can have significant effects on the
value of risky fixed-income securities. We also show that the term structure
of credit spreads can have a variety of different shapes. In addition, our
model implies that credit spreads are negatively related to the level of
interest rates. Finally, our model has many implications for hedging the
interest rate and default risk of corporate debt.
The empirical results suggest that the implications of this valuation model
are consistent with the properties of credit spreads implicit in Moody's
corporate bond yield averages. In particular, credit spreads are negatively
related to the level of interest rates. Furthermore, differences in credit
spreads across industries and sectors appear to be related to difference in
correlations between equity returns and changes in the interest rate. We also
find that changes in interest rates account for more of the variation in credit
spreads for investment-grade bonds than changes in the value of the assets of
the firm. The results provide strong evidence that both default risk and
interest rate risk are necessary components for a valuation model for corporate
debt.
Finally, we observe that while traditional approaches to modelling risky
debt provide important conceptual insights, they have not provided practical
tools for valuing realistic types of corporate securities. The primary advantage
of this model is that it is easily applied to all types of corporate debt
securities and, therefore, can be used to provide specific pricing and hedging
results rather than just general implications. In particular, the model provides
a simple theoretical benchmark against which the observed properties
of risky corporate debt prices can be compared. Future research should focus
on testing whether this two-factor model is able to explain the actual level of
corporate bond yields using detailed cross-sectional and time-series data for
individual bonds and firms.