Collusion and Antitrust Filings over the Business Cycle

Hashmat Khan and Matthew Strathearn

We develop and test a novel prediction of the theory of collusion over the business cycle. Building on Haltiwanger and Harrington (1991), we present a model of collusive behaviour in the presence of persistent demand and an Antitrust Authority (AA) in a Cournot framework. The level of collusion is higher during a boom relative to a recession as collusion occurs more frequently when demand is increasing (entering into a collusive arrangement is more profitable and deviating from an existing cartel is less profitable). The model predicts that the number of discovered cartels and hence antitrust filings should be procyclical because the level of collusion is procyclical. Using a unique data set of United States Antitrust filings, we present robust evidence consistent with the model’s prediction. We find that antitrust filings are procyclical even after controlling for AA’s monitoring intensity. The evidence suggests that procyclical competition policies may be a cost minimizing solution to asymmetries in collusive behaviour over the business cycle.

Keywords: Collusion; Cournot Competition; Antitrust Filings; Business Cycle

JEL classification: C73, L13, E32