The evidence summarized thus far indicates that empirical models of the demand for cash can explain the increase in cash holdings over time primarily through changes in firm characteristics. We rely on models that incorporate various proxies for a firm's demand for cash derived from transaction and precautionary motives for cash holdings. We have not, however, investigated directly whether variables that proxy for agency costs are related to changes in cash holdings. In this section we conduct three formal tests to evaluate whether agency problems provide a systematic explanation for the increasing cash holdings of firms in our sample