Collusion in procurement auctions: An experimental examination

Experimental methods are used to examine the existence and detectability of collusion in environments that exhibit critical parallels to procurement auctions. We find that given the opportunity sellers often raise prices considerably. Moreover, noncollusive Nash equilibrium predictions are insufficient to dismiss "suspicious" behavior as innocuous: in an environment where identical prices are predicted in a noncollusive Nash equilibrium, common prices are observed only when sellers communicate. In a second environment designed to parallel construction procurement contracting, market rotations are observed both with and without collusion, but collusion can often be detected from the pattern of losing bids.