The informational content of bond ratings

This paper explores the risk structure of interest rates. The focus is on whether yields on industrial bonds indicate that market participants base their evaluations of a bond issue's default risk on agency ratings or on publicly available financial statistics. Using a non‐linear least squares procedure, the yield‐to‐maturity is related to Moody's rating, Standard and Poor's (S&P) rating, and accounting measures of creditworthiness such as coverage and leverage. Market yields are found to be significantly correlated with both the ratings and a set of readily available financial accounting statistics. These results indicate (1) that market participants base their evaluations of an issue's creditworthiness on more than the agencies' ratings and (2) that the ratings bring some information to the market above and beyond that contained in the set of accounting variables. The paper also asks whether the market views Moody's and Standard and Poor's ratings as equally reliable measures of risk or whether the market attaches more weight to one agency's ratings than the other. Finally, the hypothesis that the market pays more attention to the accounting measures and less to the ratings if the rating has not been reviewed recently is tested.