The Dutch competition authority, the Authority for Consumers and Markets (ACM), can impose significant fines for infringements of the cartel prohibition. Once the authority has reviewed its own decision in the ‘objection procedure’, legal recourse is available against the fines imposed at the two specialised courts, the District Court Rotterdam and the Trade and Industry Appeal Tribunal (TIAT). The reason for this study was the observation that the Dutch enforcement of the European and Dutch cartel prohibition is characterised by high rates of litigation and successful litigation. As a result, the legal proceedings for resolving disputes (objection, appeal and further appeal) concerning imposed cartel fines seem to function differently than in other areas of administrative law. This observation attracted the researcher’s attention and formed the motive to dedicate a PhD thesis to analysing and explaining the high rates of (successful) litigation in Dutch anti-cartel enforcement and thereby the factors influencing those deviations. The proposed research therefore focuses on the following question: Which factors influence the high rates of litigation and successful litigation against fines for anti-competitive agreements in the Netherlands? A total of four methods were used to answer the research question: an analysis of Dutch enforcement practice, a comparison with various other national competition authorities, a comparison with four other Dutch market supervisors and interviews with practitioners, judges and officials of the competition authority. The results are divided into five articles in which (1) the TIAT’s assessment of the ACM cartel fines has been analysed and its relationship with the decisions of the Rotterdam District Court, (2) an analysis has been made of the frequency of appeals and their success in ten European Member States, (3) an analysis has been made of the factors that influence the decision to challenge the fining decision in court (4) the functioning of the objection procedure has been ...