Economic Theory

, Volume 31, Issue 2, pp 371–386 | Cite as

On Rothschild–Stiglitz as Competitive Pooling

Exposita Note


Dubey and Geanakoplos (Q J Econ 117:1529–1570, 2002) have developed a theory of competitive pooling, which incorporates adverse selection and signaling into general equilibrium. By recasting the Rothschild–Stiglitz model of insurance in this framework, they find that a separating equilibrium always exists and is unique.

We prove that their uniqueness result is not a consequence of the framework, but rather of their definition of refined equilibria. When other types of perturbations are used, the model allows for many pooling allocations to be supported as such: in particular, this is the case for pooling allocations that Pareto dominate the separating equilibrium.


Competitive pooling Insurance Adverse selection Signalling Refined equilibrium Separating equilibrium 

JEL Classification Numbers

D4 D5 D41 D52 D81 D82 


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  1. Dubey P., Geanakoplos J. (2002) Competitive pooling: Rothschild Stiglitz reconsidered. Q J Econ 117, 1529–1570CrossRefGoogle Scholar
  2. Gale D. (1992) A Walrasian theory of markets with adverse selection. Rev Econ Stud 59, 229–255CrossRefGoogle Scholar
  3. Gale D. (1996) Equilibria and Pareto optima of markets with adverse selection. Econ Theory 7, 207–235Google Scholar
  4. Gale D. (2001) Signaling in markets with two-sided adverse selection. Econ Theory 18, 391–414CrossRefGoogle Scholar
  5. Hellwig M. (1987) Some recent developments in the theory of competition in markets with adverse selection. Eur Econ Rev 31, 319–325CrossRefGoogle Scholar
  6. Kohlberg E., Mertens J.F. (1986) On the strategic stability of equilibria. Econometrica 54, 1003–1038CrossRefGoogle Scholar
  7. Rothschild M., Stiglitz J. (1976) Equilibrium in competitive insurance markets: an essay on the economics of imperfect information. Q J Econ 90, 629–649CrossRefGoogle Scholar
  8. Selten R. (1975) Reexamination of the perfectness concept for equilibrium points in extensive Games. Int J Game Theory 4, 25–55CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  1. 1.CREI and Universitat Pompeu FabraBarcelonaSpain

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