The Efficiency of Investment in the Presence of Aggregate Demand Spillovers.

In the presence of aggregate demand spillovers, an imperfectly competitive firm's profit is positively related to aggregate income, which in turn rises with profits of all firms in the economy. This pecuniary externality makes a dollar of a firm's profit raise aggrega te income by more than a dollar, since other firms' profits also rise, and in this way gives rise to a "multiplier." Since such multipliers are ignored by firms making investment decisions, privately optimal investment decisions under uncertainty will not, in general, be socially optimal. Under reasonable conditions, investmen t is too low. Copyright 1988 by University of Chicago Press.