The right to claim contribution in competition law is ensured by EU law but its exercise takes place under national laws. This Chapter investigates English, German, French and Polish rules on contribution and their application in the competition law context. On the one hand, the assessment is pragmatic. It analyses questions that are likely to appear when pursuing contribution claims. Does a right to claim contribution exist in a given legal order? On what basis and in which form can contribution be claimed? Against whom can contribution be claimed? What legal test must be met to receive contribution? What is the criterion for allocating liability between antitrust infringers? The analysis shows that the allocation of liability can be debated, as there are several possible methods of dividing liability: relative fault, causation, illicit gains, values of sales, market shares and pro capita. At the same time, the Chapter reflects on whether the requirements and modifications stemming from EU competition law require the adoption of a competition law-specific approach to contribution and makes proposals on how rules on contribution can be improved.

Claiming contribution in courts is currently a complex and uncertain task, which may lead to the unenforceability of the right to claim contribution in antitrust. The Chapter makes several recommendations that could simplify and make contribution more effective in the competition law context. Firstly, it must be clearly stated that antitrust infringers have the right to claim contribution in the context of EU competition law and that such a right does not interfere with the principle of effectiveness thereof. Secondly, rules on contribution should be the same for private and public antitrust enforcement, they should be based on one type of claim in the form of a personal right to claim contribution, available when the damages and Commission’s fine are paid. The criterion for determining internal liability should be based on a limited number of factors. A two-pillar rule based on division according to market shares and relative fault is suggested. Finally the regimes of special joint and several liability should be simplified and liability sharing agreements should be endorsed. Liability sharing agreements are the simplest and the most effective tool for securing the right to contribution.