For several years the European Commission has tried to facilitate private damage compensation claims against cartelists. The Commission aims for a better deterrence as well as for an appropriate compensation for persons harmed by a cartel. The economic literature on private enforcement of cartel law is still incomplete. Therefore the project aims to investigate the impact of compensation rules on the profitability of cartels, allocative efficiency as well as the expected effective compensation. The project focuses on the rule that cartel – harmed persons will be compensated by the amount of the actual loss of profit (lost profit compensation). This research is conducted by means of an oligopoly model and is expected to provide insights that are relevant to both the theoretical literature and applied discussions on the development of private enforcement of competition law.