This study presents an experimental test of bidder collusion in open ascending auctions with multiple objects. We conduct experiments that are designed to test the above three claims. The institution is simultaneous ascending price auction. We focus on the case of two objects.
Experimental results are largely consistent with the theory.
Collusion is often observed in two-person markets with or without complementarities. Previous experience under the same treatment greatly facilitates bidder collusion. There is no evidence of collusion in five-person markets. We further study collusive strategies adopted by bidders in two-person markets.