by Pavlína Hubková
On 2 September 2026, the General Court (GC) delivered its judgment in case Opera v. Commission (T-357/24). Its reasoning has contributed to the ongoing discussions on judicial review of decisions adopted under the DMA since it clarified the legal standing requirements of competitors seeking to challenge such decisions and provided an example of the review of their merits.
In 2024, the European Commission decided not to designate Microsoft as a gatekeeper in relation to its web browser Edge. This decision was unsurprisingly unwelcome to Opera Norway, a provider of a competing web browser. Had Microsoft been designated as a gatekeeper, Opera could have benefited from Microsoft’s compliance with Article 6(3) DMA, which would have required Microsoft to present Opera’s browser among the alternative browsers from which end users could choose their default option.
When Opera challenged the non-designation decision before the General Court, both the European Commission and Microsoft as an intervener argued that the action was inadmissible because Opera lacked legal standing. In their view, Opera was merely one browser provider among many and, moreover, had participated only marginally in the Commission’s investigation. Consequently, it did not satisfy the so-called Plaumann requirements of direct and individual concern, which would allow it to bring an action for annulment despite not being the addressee of the Commission’s decision.
However, the General Court reached a different conclusion. Building on the Plaumann judgment (25/62), as more recently clarified in Deutsche Lufthansa (C-453/19 P) and enercity (C-485/23 P), the Court held that the particular position capable of establishing individual concern must be assessed in light of two factors: the undertaking’s participation in the administrative procedure and the effects of the contested decision on its market position. Applying these criteria, the Court accepted that the non-designation of Microsoft as a gatekeeper in respect of Edge was liable to have a substantial adverse effect on Opera’s market position, as it could affect the scale of the browser’s usage. As regards Opera’s participation in the administrative procedure, the Court acknowledged that its involvement had been relatively limited. Opera was nevertheless among the competitors formally invited by the Commission to participate in the procedure and responded to the Commission’s request for information, albeit in a relatively succinct manner. Importantly, the Court considered this participation in light of the specific regulatory framework established by the DMA. Within that framework, even Opera’s relatively limited contribution to the administrative procedure was capable of supporting a finding of individual concern.
In addition, the General Court found that Opera was directly concerned by the contested decision. By declining to designate Microsoft as a gatekeeper, the Commission prevented Opera, as a provider of a competing web browser, from benefiting from the obligations that the DMA would otherwise have imposed on Microsoft. The non-designation was therefore capable of directly affecting Opera’s legal position. Moreover, the legal effects would have arisen automatically from the application of the relevant legal rules, without requiring the adoption of any intermediate implementing measures.
Consequently, Opera won the battle over legal standing.
However, this partial victory did not salvage the case: the Court reviewed the merits of the Commission’s decision and upheld its legality. Crucially, the Court acknowledged that although Microsoft met the quantitative thresholds for Edge under Article 3(2) DMA, it affirmed the Commission’s finding that Microsoft exceptionally did not satisfy the qualitative requirements listed in Article 3(1) DMA, namely that it constituted an important gateway for business users to reach end users.
The Commission’s assessment was based on four key considerations regarding the Edge browser:
- Low usage: Edge maintained a relatively minor overall market share.
- Engine dependence: Microsoft had limited control over the browser’s core architecture due to its reliance on the browser engine Blink.
- Ecosystem limits: Microsoft’s broader ecosystem did not contribute to making Edge an important gateway.
- Market feedback: Fewer than one-third of surveyed business users and market participants considered Edge an important or crucial gateway.
Opera challenged the first three considerations, arguing that they were insufficient to rebut the presumption set out in Article 3(2)(b) of the DMA. However, the Court did not agree with these claims.
Firstly, the Court upheld the Commission’s decision to compare the low usage of Edge with that of competitors such as Chrome and Safari, rather than relying strictly on absolute user numbers. The Court ruled that the importance of Edge must be evaluated in terms of the ‘overall scale’ of its activities and across all compatible devices.
Secondly, the Court agreed that Microsoft’s use of the open-source Blink engine limits its control over key browser functionality and compatibility. Consequently, the lack of architectural autonomy validly reduces Edge’s significance as an important gateway.
Thirdly, the Court upheld the argument that integration with Windows via default settings and pre-installation does not automatically make a browser a critical gateway. Despite its advantages within the ecosystem, Edge is incapable of achieving high usage levels or significantly boosting secondary services such as Bing.
Finally, the Court concluded that the Commission had conducted a thorough assessment based on reliable evidence, without omitting any decisive factors. Opera, on the other hand, had not demonstrated that the Commission had omitted any decisive factors. Furthermore, considering the additional elements invoked by Opera would not have led to a different conclusion.
Key takeaways
What seems particularly important to highlight is that the General Court established Opera’s individual and direct concern not on the basis of an actual impact of the contested decision on Opera’s legal position, but rather by reference to a hypothetical counterfactual scenario: The non-designation decision did not, as such, intervene in Opera’s legal sphere. It was merely declaratory and did not alter the existing legal status quo. Even the potential annulment of the non-designation decision would not, in itself, have directly changed Opera’s legal position, as this would have required the adoption of a new decision capable of producing such effects. However, in the specific context of the DMA, the General Court effectively flipped the perspective and grounded Opera’s direct and individual concern in its legitimate interest in Microsoft being designated as a gatekeeper. In other words, the General Court considered that had the opposite outcome occurred – i.e. had Microsoft been designated – Opera’s legal sphere would have been directly and individually affected.
It follows that while Opera was ultimately unsuccessful in getting the Commission’s non-designation decision annulled, its victory on legal standing remains an important procedural takeaway and opens the door for smaller competitors challenging similar decisions in the future. By applying the Plaumann test in the context of digital ecosystems, the General Court confirmed that competitors – even if they are not the addressees of a designation or non-designation decision – can effectively seek judicial review of the merits.
Of course, it is possible that the General Court’s judgment will be challenged in the Court of Justice. However, let us hope that the Court of Justice will not overturn the decision on admissibility, because acknowledging the legal standing of competitors such as Opera is particularly important in cases where decisions are negative: when the Commission finds that an investigated undertaking does not meet the requirements to be designated a gatekeeper, that undertaking has no reason to appeal. While privileged applicants could theoretically step in, smaller competitors are far more likely in practice to launch a challenge. By granting legal standing to competitors who are directly and individually concerned through a hypothetical counterfactual scenario, the judicial system also upholds the rule of law by ensuring that non-designation decisions remain subject to judicial oversight.
