In his opinion of 28 October 2021, Advocate General Rantos confirmed that the nature of the rules implementing the EU Damages Directive is determined by EU law and not by national law. The Advocate General states that the provisions on limitations and presumption of cartel-related harm are substantive. In contrast, the possibility for national judges to estimate the amount of harm is a procedural provision. Moreover, AG Rantos considers that pre-Directive knowledge-based limitation periods applied to cartel damage claims could reasonably begin with the publication of a fining decision’s multilingual summary.