Three economic environments are reviewed and, in each, organizations play an essential role. For an adve rse selection insurance economy, the authors find that when mutual in surance arrangements are permitted, an equilibrium necessarily exists and is optimal. This example, and two others,...

Three economic environments are reviewed, and in each organizations play an essential role. For an adverse selection insurance economy, we find that when mutual insurance arrangements are permitted an equilibrium necessarily exists and is optimal. This example, and the two others, illustrate the...