Abstract

The adoption of leniency programs in several countries has extended the role of whistle-blowers in enforcing antitrust law. However, antitrust scholars have focused on the regulation of whistleblowing in case of cartels. This paper studies the empirical relevance of whistle-blowers in a broader area and considers all proceedings regarding cartels and dominant positions concluded in Italy between 1994 and 2019. The results show that external whistle-blowers account for more than 90 percent of complaints and are therefore crucial in detecting breaches of competition law. A probit analysis explores the association between identity of complainants, characteristics of antitrust cases and outcome of proceedings. Broadly speaking, this paper identifies the areas where additional incentives to report alleged violations could increase external collaboration and enhance the efficiency of antitrust enforcement.