Supplement to "Efficient Competition through Cheap Talk: The Case of Competing Auctions"

Appendix A provides a formal analysis of the finite market model introduced in Section 4.  Appendix B considers a finite competing (procurement) auctions model with reserve price posting and show that the market outcome is not constrained efficient whenever there are at least three procurers and at least two of them are heterogeneous. Appendix C constructs the set of all interval partitional equilibria, which includes the fully revealing equilibrium as a special case.  Then it shows that the fully revealing equilibrium uniquely satisfies neologism proofness by Farrell (1993).  Appendix D shows that the fully revealing equilibrium exists even if agents are risk averse. Appendix E demonstrates that our main result continues to hold even when contractors are heterogeneous. 

Supplemental Authors: 
Kim, Kyungmin - Emory University
Kircher, Philipp - European University Institute