ABSTRACT We argue that corporate bond yields reflect fears of debt deflation. When debt is nominal, unexpectedly low inflation increases real liabilities and default risk. In a real business cycle model with optimal but infrequent capital structure choice, more uncertain or procyclical inflation leads to quantitatively important increases in corporate log yields in excess of default‐free log yields. A panel of credit spread indexes from six developed countries shows that credit spreads rise by 14 basis points if inflation volatility or the inflation‐stock correlation increases by one standard deviation.

We examine whether fundamental measures of volatility are incremental to market-based measures of volatility in (i) predicting bankruptcies (out of sample), (ii) explaining cross-sectional variation in credit spreads, and (iii) explaining future credit excess returns. Our fundamental measures of volatility include (i) historical volatility in profitability, margins, turnover, operating income growth, and sales growth; (ii) dispersion in analyst forecasts of future earnings; and (iii) quantile regression forecasts of the interquartile range of the distribution of profitability. We find robust evidence that these fundamental measures of volatility improve out-of-sample forecasts of bankruptcy and help explain cross-sectional variation in credit spreads. This suggests that an analysis of credit risk can be enhanced with a detailed analysis of fundamental information. As a test case of the benefit of volatility forecasting, we document an improved ability to forecast future credit excess returns, particularly when using fundamental measures of volatility.