A Rule-of-Thumb Theory of Cash Holdings by Firms

Models developed to explain variations in cash balances of firms have generally postulated forms of rational choice for the decision maker. Two examples of these kinds of models are (1) Baumol's inventory-type model where the choice of the initial balance is made in terms of a planning period in which outflows of cash, but no inflows, are considered; (2) Miller and Orr's model wherein inflows and outflows occur randomly and a decision is triggered to increase or reduce cash balances when an upper or lower threshold is passed. Statistical tests of the inventory-type model have had limited success, particularly in attempts to identify the increasing efficiency in the use of cash balances as a function of the size of the firm. The apparent linear double logarithmic relationship between cash balances of firms and their sales volumes has cast doubt upon the increased efficiency proposition that derives from the Baumol model. Meltzer has modified this model to demonstrate that it implies linearity. The Meltzer tests will be challenged in this paper, and we shall establish that his results, as well as Baumol's conclusions, are particular outcomes that can be better explained in another type of model.