The actual content of the right to be compensated for damage suffered as a result of the infringement of the competition rules is affected by the expansive nature of these particular losses, which can be passed by the directly injured party to other market participants. The substantive and procedural legal consequences of the pass-on of the harm, which may be alleged by both the plaintiff indirect purchaser (as "sword") and the defendant infringer (as "shield"), are only partially harmonized by the Damages Directive. They are therefore largely governed by national rules, which cannot undermine the effectiveness of the Treaty’s competition rules. In this regard, increasing harmonization in this area is also taking place incrementally through the case law of the Court of Justice, particularly on the configuration of the causal relationship.
Therefore, while some of the legal issues raised by the passing-on of damage relating to standing, to the legal link between the infringement and the passing-on and to the quantification of the compensable damage have been resolved, others have yet to be decided by the national courts or, where appropriate, by the Court of Justice.