Recent theoretical models (Carlson, Fisher, and Giammarino, 2004) predict an association between the book-to-market equity ratio (BE/ME) and operating leverage in the cross-section. Consistent with these models, we find a positive association between BE/ME and the degree of operating leverage (DOL), between DOL and stock returns, and between DOL and systematic risk. Overall, our findings provide support for a risk-based explanation for the value premium that is consistent with existing theoretical models. The evolution of systematic risk associated with firm-level investment activity, rather than financial distress, seems to be the main determinant of the value premium.