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Optimal collusion-proof auctions

Che, Yeon-Koo; Kim, Jinwoo

We study an optimal collusion-proof auction in an environment where subsets of bidders may collude not just on their bids but also on their participation. Despite their ability to collude on participation, informational asymmetry facing the potential colluders can be exploited significantly to weaken their collusive power. The second-best auction - i.e., the optimal auction in a collusion-free environment - can be made collusion-proof, if at least one bidder is not collusive, or there are multiple bidding cartels, or the second-best outcome involves a nontrivial probability of the object not being sold. In case the second-best outcome is not weak collusion-proof implementable, we characterize an optimal collusion-proof auction. This auction involves nontrivial exclusion of collusive bidders - i.e., the object is not sold to any collusive bidder with positive probability.

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Academic Units
Economics
Publisher
Department of Economics, Columbia University
Series
Department of Economics Discussion Papers, 0708-05
Published Here
March 28, 2011

Notes

September 2007