We study an economy with traders whose payoffs are quasilinear and their private signals are informative about an unobserved state parameter. The limit economy has infinitely many traders partitioned into a finite set of symmetry classes called types. It has a unique rational expectations...

It is well-known that the ability of the Vickrey-Clarke-Groves (VCG) mechanism to implement efficient outcomes for private value choice problems does not extend to interdependent value problems. When an agent's type affects other agents' utilities, it may not be incentive compatible for him to...

We study when equilibrium prices can aggregate information in an auction market with a large population of traders. Our main result identifies a property of information---the betweenness property---that is both necessary and sufficient for information aggregation. The characterization provides...