A Field Experiment on Antitrust Compliance

We study the effectiveness of firms' compliance programs by conducting a field experiment in which we disclose to a subset of Japanese firms that the firm is potentially engaging in illegal bid-rigging. We find that the information that we disclose affects the bidding behavior of the treated firms: our test of bid-rigging is less able to reject the null of competition when applied to the bidding data of the treated firms after the intervention. We find evidence that this change is not the result of firms ceasing to collude, however. We find evidence suggesting that firms continue to collude even after our intervention and that the change in the bidding behavior we document is the result of active concealment of evidence by cartelizing firms.