Since 1996, the European Commission has been operating a leniency programme, under which companies cooperating with its cartel investigations can obtain immunity from fines or a reduction of fines. Leniency plays a prominent role in EU cartel enforcement today. This paper assesses the positive effects and the possible negative effects of leniency, in the light of twenty years of experience.
1. Overview of the applicable provisions
1. According to the definition provided by the EU legislator, a “leniency programme” is “a programme (…) on the basis of which a participant in a secret cartel, independently of the other undertakings involved in the cartel, cooperates with an investigation of the competition authority, by voluntarily providing presentations regarding that participant’s knowledge of, and role in, the cartel in return for which that participant receives (…) immunity from, or a reduction in, fines for its involvement in the cartel.” 
2. The European Commission adopted its first Leniency Notice in 1996.  This initial Leniency Notice was replaced by a new one in 2002.  The main changes were that immunity became automatic, and that fine