This paper analyses the development of private actions for damages as a significant pillar of private enforcement of EU competition law and discusses the quantification and estimation of harm. Since the adoption of the EU Directive 2014/104/EU on Antitrust Damages Actions, private enforcement in Europe has undergone crucial clarifications in the case law of EU courts, yet the critical issue of quantifying damages in private actions has only recently been addressed by the Court of Justice of the European Union (CJEU). This paper takes a closer look at the recent ruling in the Tráficos Manuel Ferrer case (C-312/21) and assesses the implications of that case law for private enforcement proceedings. Concerning the allocation of procedural costs, this judgment has established that injured parties may be required to bear a cost risk, even if they are partially successful. This finding needs further reflection in the context of consumer claims for damages, as it is susceptible to add an additional cost burden on plaintiffs. The second intricate finding concerns the relation between the ability of national courts to estimate damages and the exhaustion of evidence disclosure. Taking the example of Spain, the paper advocates for the specific inclusion of the principle of proportionality when determining harm in private actions for damages and especially in cases involving consumers or smaller harmed parties.