Deterrence of Antitrust Violations: Do Actions for Damages Matter in Japan?

There is considerable debate about the role private litigation should play in the enforcement of antitrust law. This article focuses on one of the most controversial private enforcement mechanisms - damages actions - and assesses whether and how much such actions have contributed to deterring antitrust violations in Japan. It does so by answering two questions: (1) how much have damages actions contributed to the detection of antitrust violations?, and (2) how much have damages actions contributed to an increase in the sanctions for antitrust violations? Based on original data concerning damages actions between 1990 and 2010, the article argues that damages actions have somewhat contributed to deterring certain antitrust violations, bid-rigging in particular, but that an almost equivalent measure of deterrence could have been generated more efficiently by imposing higher penalties through public enforcement.