Productivity and costs for firms in presence of technology renewal processes

Wide empirical analyses investigated the size and growth rate distribution of business firms, providing a relevant empirical support to economic theory. We rely on such analyses and on studies on technology renewal costs and productivity, in order to draw sufficient conditions for the optimality of firms' profit with respect to time. The relationships that hold among productivity, costs of renewal and growth rates of the companies at the optimal profit time are shown, and suggestions for firms' policies are proposed.