Intertemporal Insurance

This paper develops a discrete-time general equilibrium model of insurance using standard techniques of intertemporal finance. The underlying source of uncertainty is modeled as a marked point process. The paper begins by characterizing Walrasian equilibrium on the event tree generated by the accident process. The corresponding Arrow-Debreu-Radner contingent-commodity prices allow the pricing of insurance contracts. A transformation of the underlying probability measure gives an alternative characterization of insurance contract prices plus accumulated payouts as martingales. A direct application of the usual dynamic spanning argument demonstrates that one insurance contract for each type of accident suffices, at least generically, to achieve market completeness. The theory is illustrated by a simple example in which consumers have Cobb-Douglas preferences and experience accidents at a rate which varies across individuals but remains constant over time, the traditional setting for much of insurance theory. This paper was presented at the Financial Institutions Center's May 1996 conference on "

Clubs and the Market

This paper defines a general eqilibrium model with exchange and club formation. Agents trade multiple private goods widely in the market, can belong to several clubs, and care about the characteristics of the other members of their clubs. The space of agents is a continuum, but clubs are finite. It is shown that (i) competitive equilibria exist, and (ii) the core coincides with the set of equilibrium states. The central subtlety is in modeling club memberships and expressing the notion that membership choices are consistent across the population.clubs; continuum models; public goods; core; club equilibrium

A Theory of Firm Formation and Skills Acquisition

We present a theory of production that begins with an exogenously specified set of technologies, accessible to each potential firm. The technologies used in equilibrium are endogenous. Labor skills are differentiated, and the labor skills are acquired endogenously by workers, possibly by bearing private costs, and possibly by attending school. A technology can be used by a group of agents having the appropriate skills. We allow that workers care about the production plans in their firms, and will accept lower compensation to satisfy their preferences on production plans. In a continuum model, we show what price systems are required so that competitive equilibrium exists and core outcomes are equivalent to competitive outcomes.