Detecting Large-Scale Collusion in Procurement Auctions

We document evidence of widespread collusion among construction firms in Japan using a novel data set covering most of the construction projects procured by the Japanese national government. Our data set contains information on about 42,000 auctions whose award amount sums to about $40 billion. We identify collusion by focusing on rebids that occur for auctions in which all (initial) bids fail to meet the secret reserve price. We identify more than 1,000 firms whose conduct is inconsistent with competitive behavior. These bidders were awarded about 15,000 projects, or about 37% of the total number of projects in our sample.