second, we examine the value of cash holdings over time. A number of recent papers correlate agency costs of cash with the value of corporate cash holdings. We follow the approach in Pinkowitz and Williamson (2004), which uses a valuation regression developed by Fama and French (1998) and modifies it by introducing cash holdings as an independent variable. While this approach is ad hoc in that it does not specify a functional form that results directly from a theoretical model, it explains a substantial amount of the cross-sectional variation in firm values. Their basic regression specification is as follows: