Working paper (Federal Reserve Bank of Minneapolis. Research Dept.)
General competitive analysis is extended to cover a dynamic, pure-exchange economy with privately observed shocks to preferences. In the linear, infinite-dimensional space containing lotteries we establish the existence of optima, the existence of competitive equilibria, and that every competitive equilibrium is an optimum. An example illustrates that rationing and securities with contrived risk have an equilibrium interpretation.
A necessary feature for equilibrium is that beliefs about the behavior of other agents are rational. We argue that in stationary OLG environments this implies that any future generation in the same situation as the initial generation must do as well as the initial generation did in that situation. We conclude that the existing equilibrium concepts in the literature do not satisfy this condition. We then propose an alternative equilibrium concept, organizational equilibrium, that satisfies this condition. We show that equilibrium exists, it is unique, and it improves over autarky without achieving optimality. Moreover, the equilibrium can be readily found by solving a maximization program.