The lack of widely available and comprehensive data of default activity on the corporate level has encouraged the advance of theories of corporate credit risk far beyond related empirical work. This article addresses this deficit by examining a unique data set—corporate bond defaults and credit ratings compiled by Moody's Investors Service since 1920. The article investigates the time inhomogeneity of company default risk—that is, the pattern in which the risk of default for a company changes over time. The empirical analysis addresses company default risk within a regression framework of competing risks, or hazards. The analysis identifies (and quantifies) variations in default risk with macroeconomic conditions, with industries, and through time—an important characterization for many approaches to measuring and managing credit risk.