An important body of literature in Financial Economics accepts bond ratings as a sufficient metric for determining homogeneous groups of bonds for estimating either risk-neutral probabilities or spot rate curves for valuing corporate bonds. In this paper we examine Moody’s and Standard & Poors ratings of corporate bonds and show they are not sufficient metrics for determining spot rate curves and pricing relationships. We investigate several bond characteristics that have been hypothesized as affecting bond prices and show that from among this set of measures default risk, liquidity, tax liability, recovery rate and bond age leads to better estimates of spot curves and for pricing bonds. This has implications for what factors affect corporate bond prices as well as valuing individual bonds.

ABSTRACT The purpose of this article is to explain the spread between rates on corporate and government bonds. We show that expected default accounts for a surprisingly small fraction of the premium in corporate rates over treasuries. While state taxes explain a substantial portion of the difference, the remaining portion of the spread is closely related to the factors that we commonly accept as explaining risk premiums for common stocks. Both our time series and cross‐sectional tests support the existence of a risk premium on corporate bonds.