On June 5, 2025, the Spanish Supreme Court issued a ruling that marks a milestone in private competition law enforcement in Spain. The judgment — STS 2621/2025 — resolves the appeal brought by the Partido Socialista Obrero Español (PSOE) against several companies in the paper envelope sector — namely Printeos, Tompla, and Maespa — which had been fined in 2013 by the Comisión Nacional de la Competencia (CNC) for participating in a cartel (case S/0316/10).
The ruling consolidates and refines the case law and criteria on five crucial aspects for damages actions stemming from infringements of competition law: (i) the starting point for the limitation period, (ii) the evidentiary value of the administrative decision, (iii) the judicial estimation of the damage, in this case a 20% linear overcharge, (iv) the interpretation of the pass-on defence in cases involving partial public subsidies, and (v) the method for calculating compensatory interest. These elements are essential to ensure that victims of anticompetitive practices and those harmed by any abuse of a dominant position within the internal market, as prohibited under EU competition law, have access to full compensation.
Limitation Period: Finality of the Decision as the Starting Point
One of the main pronouncements in the Supreme Court’s decision is the confirmation that the five-year limitation period for claiming damages — introduced through the transposition of Directive 2014/104/EU (Damages Directive) and transposed into Spanish law through Article 74 of the Competition Act (LDC) in 2017 — only begins when the infringement decision becomes final.
Importantly, the Court clarified the temporal application of this limitation period. Since the Damages Directive itself does not contain specific transitional provisions, the relevant date to determine the applicable prescription regime is the “dies ad quem” (cut-off date) for the Directive’s transposition, which was 27 December 2016. The Court followed the CJEU’s interpretation that if the limitation period applicable under previous rules had not expired by that date, then the new five-year limitation period introduced by the Directive and Spanish law applies.
The Court recalls that, in accordance with CJEU case law (e.g., Judgment of 22 June 2022, Case C-267/20, Volvo AB and DAF Trucks), the limitation period cannot begin until the injured party has actual or potential knowledge of all the elements necessary to bring a claim — including the unlawful conduct, the identity of the infringer, the harm suffered, and the causal link. According to the Supreme Court, these elements require a complex legal and factual assessment, which cannot begin while the decision is still subject to judicial review.
Even in the case of a leniency beneficiary, such as Tompla, if appeals by other cartel participants are still pending on substantive matters, the Court considers the decision not to be final, and therefore the limitation period does not start running.
Furthermore, the Court refuses to directly apply the Heureka doctrine (CJEU, C-605/21), which considers that publication in an official journal may be sufficient to trigger the limitation period. In the envelopes case, the infringement decision was not published in any official journal, and the Court holds that its dissemination on the CNMC website cannot be equated to a formal publication.
This approach enhances legal certainty for victims, protecting them from the risk of their claims being time-barred while judicial review of the administrative decision is still pending.
In addition, regarding the potential impact of the pending CJEU ruling in case C-21/24 Nissan Iberia, the Supreme Court rejected requests to stay Spanish proceedings until the CJEU decision is issued. Specifically, although the claimant submitted the Advocate General’s opinion issued on 3 April 2025[1], and the defendant requested suspension of the case pending the CJEU ruling, the Court held that suspension was not required, and the case should proceed.
Harm and the Evidentiary Value of the CNMC Decision
Another crucial aspect is the strengthening of the evidentiary value of the infringement decision. The Supreme Court reinforces the presumption of harm derived from an infringement by object, even when the CNMC does not explicitly quantify the effects or damages suffered by the affected parties.
The judgment reiterates that an object-based infringement distorts competition by its very nature. Therefore, it is not necessary for the authority to detail its specific effects in each case. The mere existence of the cartel — particularly the exchange of information and price collusion — allows the civil court to reasonably presume that economic harm occurred.
According to the Supreme Court, even the mere exchange of sensitive information between competitors is considered a distortion of competition that most likely results in price increases. This logic is even more compelling when, as in the present case, there is evidence of coordinated price-setting agreements.
This doctrine, already initiated in the trucks cartel case, is now further consolidated as a stable line of jurisprudence, facilitating access to compensation even in contexts where victims have incomplete or asymmetric information.
Overcharge Calculation: Judicial Estimation of a 20% linear overcharge
The Supreme Court Judgment provides relevant insights into how Spanish courts may address the quantification of damages arising from anticompetitive practices when expert evidence is insufficient or deficient. In this case, both the first instance Commercial Court and the second instance Provincial Court upheld the application of a flat 20% percentage over the amount of purchases made during the cartel period (1985–2010) as a judicial estimation method for the overcharge.
The Supreme Court confirmed that this approach is justified for several reasons. First, the insufficiency of the expert reports submitted, particularly by the plaintiff, whose report was rejected for relying on scarce and unrepresentative reference prices. Second, the existence of objective data and information contained in the CNMC’s sanctioning decision, which evidenced significant overpricing practices during the duration of the cartel. Among this data were discounts granted after the cartel period of 21%, 35%, and up to 40%, in contrast to discounts below 10% during the cartel period.
Furthermore, specific comparisons have been considered by the courts, such as the offer from Cayfosa (a non-cartel member) for the 1994 European Parliament elections, which was 23.2% lower than the price offered by Unipapel (a cartel member), as well as other internal documentary evidence from cartel participants (such as the 2001 Tompla document estimating a 20% price drop following the entry of a new competitor).
One of the most relevant contributions of this judgment is the annualized structure of the calculation: each year’s purchases during the cartel period must be treated autonomously for the purposes of quantifying and capitalizing the damage (applying compound legal interest from the date of each purchase until the filing of the claim, see below). In this regard, the Supreme Court stresses that the principle of procedural congruence prevents an offsetting between years: if the overcharge claimed in one year is below the 20% judicial estimate, the amount claimed is awarded; if it exceeds 20%, only the 20% is awarded, no more.
The judgment also clarifies how the impact of public subsidies (in this case, earmarked subsidies for sending electoral envelopes) should be treated. Only those elections in which the subsidy fully (i.e. to 100%) covered the cost of envelopes acquisition are excluded from the calculation. In all other cases, the overcharge is applied proportionally to the part of the price not covered by the subsidy, consistent with the principle of full compensation.
In short, this ruling consolidates the use of the power of judges to reasonable judicial estimations of the overcharge in cases of lack of reliable economic expert evidence, taking into account especially factual circumstances established in the context of the investigation by the Spanish competition authority.
Rejection of the Pass-On Defence
One of the defences raised by the defendants was that the alleged harm was absorbed through public subsidies received by the PSOE for financing electoral campaigns. The Supreme Court rejects this argument and sets a clear criterion: harm can only be excluded if the subsidy covered 100% of the cost related to the purchase of envelopes.
Where funding is partial — even if it covers 99% — harm still exists in the uncovered portion and must be fully compensated. Moreover, if the subsidy is not earmarked (i.e., not specifically intended to cover the cost of envelopes), it cannot be deemed to have neutralized the harm.
The Court emphasizes that accepting partial compensation as evidence of pass-on would violate the principle of full compensation, which requires complete and effective redress of the harm suffered.
Thus, the overcharge must be calculated on the portion of the expenditure not covered by the specific subsidy, applying the estimated overcharge percentage (in this case, 20%), as mentioned above, to the remaining amount.
This criterion establishes a solid guideline for future cases where pass-on is claimed based on public funding or other forms of indirect compensation to the harmed party.
Compound Legal Interest: A Requirement for Full Compensation
Finally, the Supreme Court adopts a favorable stance towards the use of compound legal interest as the appropriate mechanism to update the value of the harm from the moment it occurred, until its effective redress.
The compound interest method — expressly recommended by the CNMC in its 2023 Guidance on the quantification of damages [2]— properly reflects both the loss of purchasing power and the inability to reinvest the funds. Unlike simple interest, which only applies interest on the initial principal, compound interest accounts for the accumulated interest over each period, yielding a more economically accurate and fair outcome.
The Supreme Court notes that, unless proven otherwise, this is the appropriate approach to comply with the principle of full compensation, particularly in cases where harm persists over long periods, as is often the case in competition litigation.
Conclusion: A Judgment providing Guidance for Private Enforcement in Spain
STS 2621/2025 represents a decisive step forward in consolidating the rights of victims of anticompetitive practices. It provides legal certainty on key issues such as limitation periods, the evidentiary value of infringement decisions, limits to the pass-on defence, and the proper method for calculating compensatory interest.
In line with CJEU case law and through a coherent interpretation of the Spanish legal framework, the Supreme Court takes a firm step toward building an effective private enforcement system for competition law. This ruling is not only pivotal for the envelopes cartel case, but also sets a strong precedent for future litigation in this field — and as such, deserves to be regarded as one of the most important decisions in the recent history of Spanish competition law.
[1] See our blog post on Advocate General Medina’s opinion in Case C‑21/24, CP v Nissan Iberia, where she confirms that the limitation period for bringing an action for damages cannot begin until judicial review of the infringement decision has been completed. AG Medina’s reasoning is fully in line with the approach taken by the Spanish Supreme Court, which developed the concept of ‘full aptitude to litigate’. Available ici.
[2] See CNMC, Guía para la cuantificación de los daños por infracciones del Derecho de la competencia, 2023, available ici, where the authority expressly recommends the use of the compound interest method (see section 2.4.1. “Métodos de cálculo de la capitalización”).
By Amelia Mora González and Till Schreiber
