Marktmachtmissbrauch durch Verstoß gegen außerkartellrechtliche Rechtsvorschriften

The initiation of proceedings against Facebook by the German Federal Cartel Office on suspicion of the abuse of a dominant position rekindled the debate on the question of which role breaches of non-antitrust legal provi-sions play in the assessment of an abuse of a dominant position. The author carries out a comprehensive analysis of the differentiated positions and the previous decisional practice with regard to this question and references to the protective purpose of antitrust law as well as to the differentiation from unfair competition law. She concludes that a breach of data protection law by a dominant business does not constitute an exploitative abuse but falls within the scope of an exclusionary abuse if the breach leads to an increase of network and lock-in effects, which entail a competitive advantage for the dominant business and the increase of market entry barriers for (potential) competitors.