WAMCA: When an “event” determines the regime – but not the case

In its judgment of 23 December 2025 (ECLI:NL:GHDHA:2025:2738), the Hague Court of Appeal addressed in detail the transitional regime governing the shift from the former Dutch collective action framework (old Article 3:305a of the Dutch Civil Code) to the WAMCA (the Act on the Resolution of Mass Damage in Collective Action).

The case concerned a collective investor action, initiated by a claim foundation, against Airbus SE, certain (former) directors and the auditor, raising the threshold question as to which collective action regime applied: the pre‑WAMCA regime or the WAMCA. Which regime applies temporally matters because it affects, among other things, the admissibility requirements and (in broad terms) whether collective monetary relief may be pursued. As a general matter, collective monetary relief as part of the collective action is only admissible under the WAMCA regime.

Although this is a transitional‑law question, answering it presupposes an “event” demarcation exercise: does the relevant factual matrix qualify as one “event” (or a series) or as multiple, distinct events?

The alleged conduct: not bribery per se, but “information failure”

Over a period of several years, Airbus was investigated in relation to bribery and corruption concerns, culminating in coordinated enforcement resolutions in early 2020. The claim foundation did not base its case primarily on the underlying bribery allegations within the Airbus group as such. Instead, it framed the claim around an alleged prolonged failure to inform investors accurately, fully and without misleading omissions. The foundation alleged that Airbus systematically omitted adequate disclosure in its financial and ad hoc publications regarding (i) the scale and nature of bribery practices, (ii) their institutionalisation within the business, (iii) internal and external investigations, and (iv) the related financial risks.

This alleged “information failure” was said to have inflated the share price, causing losses for investors who acquired or held shares at an artificially high level. The pleaded wrong was therefore constructed around breaches of disclosure and market disclosure obligations, rather than the bribery acts themselves.

The legislative rationale: a measured temporal gateway (15 November 2016)

When introducing the WAMCA, the legislature adopted a carefully calibrated transitional regime, driven by legal certainty: the new framework should not become indefinitely available for older fact patterns. The relevant cut‑off date is 15 November 2016, the date the WAMCA proposal was made public, so that parties could in principle anticipate the forthcoming procedural regime.

The legislative materials emphasise that the court should anchor the transitional test to the damage‑causing “event(s)” on which the claimant organisation bases its collective claim. Where the claim concerns a series of events spanning both before and after 15 November 2016, the explanatory materials indicate that the applicable regime follows the law in force at the time of the last event in the series. This approach is intended to limit strategic “slicing” and manipulation, while still requiring material coherence.

The Court of Appeal underscores in this context that the starting point is the damage‑causing event(s) as pleaded by the claimant organisation, rather than an “objectively” selected background fact.

The Court’s characterisation: one continuing damage‑causing event

The Court of Appeal explicitly aligns its analysis with the legislative intent. It rejects the argument that the court should anchor the transitional regime either to the underlying bribery conduct or to the beginning of the alleged information failure before 15 November 2016. Instead, the decisive question is which event – as framed in the claim – allegedly caused the impairment of investors’ financial interests and thus the asserted loss.

On that basis, the Court identifies the relevant event as Airbus’s continuing omission to inform investors properly, spanning from 2014 until at least March 2020. Individual disclosures and publications are not treated as separate damage‑causing events; rather, they are treated as manifestations of a single continuing state of affairs. The Court therefore characterises the pleaded conduct as one continuing event ending after 15 November 2016.

Stepping back, the reasoning has a familiar structure for readers used to insurance aggregation disputes: (i) first identify the correct anchor for the analysis (here, the pleaded damage‑causing omission), (ii) then decide whether individual manifestations should be treated as stand‑alone events or as expressions of one continuing underlying phenomenon, and (iii) finally ensure that the demarcation is not an artificial construct. In insurance terms, this mirrors the logic that often sits behind an aggregation (series/related claims) clause – albeit with a crucial difference: in insurance the decisive anchor is the policy wording and its interpretation, not legislative history. That is why the same demarcation logic can, depending on definition and fact pattern, produce either aggregation or multiple distinct claims (compare, for example, ECLI:NL:GHDHA:2025:467 with ECLI:NL:GHAMS:2024:563 and ECLI:NL:RBDHA:2020:14195).

Result on transitional law: WAMCA applies, but the claim still fails procedurally

Against that background – with the relevant “event” characterised as one continuing damage‑causing omission – the follow‑on question is which temporal regime applies. Consistently with the rationale of the transitional provisions, the Court held that the applicable regime is the law in force at the time the continuing damage‑causing event ends. Because the alleged omission continued beyond 15 November 2016, the WAMCA applies to the claim. The Court adds that this approach does not offend legal certainty: once the legislative proposal was public, Airbus could in theory have altered its information conduct to avoid the WAMCA being triggered by a continuing omission.

This means the claim foundation wins the transitional‑law argument: the Court treats the pleaded conduct as a single continuing damage‑causing event and thus reaches WAMCA applicability.

However, that victory proves largely pyrrhic. Under the WAMCA, claim foundations are subject to a more stringent set of admissibility safeguards, including requirements aimed at governance and funding transparency, intended to ensure that control of the litigation remains with the claim foundation. The Court held the claim of the claim foundation inadmissible because the represented interests were insufficiently safeguarded, in particular because the foundation lacked sufficient control over the litigation in light of its funding and operational structure. As a result, the Court does not reach any substantive determination of liability or quantum.

More generally, the judgment illustrates how the notion of an “event” can operate as a legal hinge: its demarcation determines the procedural regime, and it can also be outcome‑determinative before the court ever reaches the merits.

WAMCA - admissibility requirements

As noted: the Court of Appeal held the claim of the claim foundation inadmissible. The Court based that decision on the relatively stringent WAMCA admissibility requirements. We note that these requirements are subject to criticism. A case on this subject is currently pending before the Dutch Supreme Court. In that case, Advocate General R.H. de Bock of the Supreme Court of the Netherlands has issued an advisory opinion (a “Conclusion”; ECLI:NL:PHR:2026:129) advising the Supreme Court that the WAMCA legislature did not intend for excessively high thresholds for litigation by interest groups (such as the claim organisation in the Airbus case). This Conclusion post-dates the Airbus judgment discussed above and briefly refers to Airbus as part of the broader discussion on third-party funding, control and the WAMCA admissibility framework.

The advisory opinion goes on to state that the admissibility requirements must be seen against the background of the purpose of the WAMCA, namely, to promote the efficient and effective resolution of mass damages. Admissibility requirements should therefore not be interpreted in such a way that they effectively obstruct the bringing of a collective action by an organisation established for that very purpose (such as the claim organisation in the Airbus case). According to this Advocate General, WAMCA admissibility requirements do not consist of rigid rules, but rather of open norms that allow for interpretation in light of the specific circumstances. According to the Advocate General, the Court should have a large degree of discretion. This discretion could lead to more lenient admissibility rulings. The judgment of the Supreme Court is now awaited and is expected in early summer 2026.