Above the thresholds, below the bar: takeaways from the EU’s General Court on rebutting a DMA gatekeeper presumption

General Court (Eighth Chamber, sitting with five Judges), judgment of 2 September 2026, Case T-357/24 – Opera Norway AS v European Commission

Under the DMA, crossing certain user and financial thresholds creates a presumption that the criteria for gatekeeper status are met; the Commission then designates the undertaking as a gatekeeper unless the presumption is rebutted.

The General Court’s dismissal on 2 September 2026 of Opera Norway’s challenge to the decision not to designate Microsoft as a gatekeeper for the Edge web browser addresses three aspects of that question: how relevant low usage is to whether a service is an important gateway, what evidence is admissible, and how ecosystem advantages are weighed.

How designation and rebuttal work under the DMA

An undertaking is designated as a gatekeeper in respect of a core platform service where it has a significant impact on the internal market, the service is an important gateway for business users to reach end users, and it enjoys an entrenched and durable position. Those criteria are presumed met once the quantitative thresholds are crossed, and the undertaking must notify the Commission within two months — but it may present, with its notification, sufficiently substantiated arguments that, exceptionally, and due to the circumstances in which the service operates, the criteria are not met.

That is the route Microsoft took for Edge (alongside Bing and Microsoft Advertising), all of which met the notification thresholds. The Commission designated Microsoft as a gatekeeper in respect of the Windows PC operating system and LinkedIn, and decided to open a market investigation to assess in more detail whether or not to designate also Edge, Bing and Microsoft Advertising, closing that investigation in February 2024 without designating any of them.

Thresholds are not decisive where engagement is thin

Last week’s judgment confirmed that crossing the user number thresholds does not establish that a service is an important gateway, nor is a strong position on one platform sufficient.

The DMA’s recitals expressly name the “overall scale of activities of the respective [core platform service]” (Recital 23 DMA) among the elements directly related to the quantitative criteria. The Court found the Commission may therefore take a low scale of usage into account, and may compare it with that of other services, the list of relevant elements not being exhaustive. According to the Commission’s findings, Edge accounted for only 5.8% of web page views across all device types in Europe in December 2022, which was significantly below the share of other web browsers. The Court further rejected that the assessment could be confined to the platform where Edge was strongest: the importance of web browsers “cannot be assessed exclusively by reference to a single group of devices or operating systems by which they are proposed”.

Wide rein for evidence a rebuttal can rest on

The judgment also addresses which evidence may be relied on in a rebuttal, for the undertaking and the Commission alike, and treats the categories excluded as narrow ones.

Designation is meant to be a fast exercise — the Commission has 45 working days from a complete notification — resting on the criteria the DMA itself sets rather than on an inquiry into market power, which is why certain economic justifications are excluded altogether.

On the Court’s reading, the room for rebuttal evidence is nonetheless wide: only arguments “deriving from a justification on economic grounds seeking to enter into market definition or to demonstrate efficiencies” are excluded from the outset, and in principle any element directed at rebutting a presumption “concretely and specifically” may be taken into account. Opera argued that the Commission had strayed into that exclusion by expressing Edge’s usage as a share of total web page views. The Court disagreed, since a market share presupposes a market first defined by product and by geography, and none had been defined.

Ecosystems count for what they deliver

On the Court’s approach, distribution advantages count only in so far as they show up in how much the service is used.

It is the benefits or disadvantages associated with the existence of an ecosystem, “and not the mere existence or absence of an ecosystem as such”, that permit, in the Court’s view, an assessment of gateway importance, and each ecosystem must be examined case by case. Edge is part of Microsoft’s ecosystem: pre-installed on Windows, incentivised as the default with equipment manufacturers, and pinned to the task bar. But those advantages had not converted into use. Across all devices, competing browsers that are not pre-installed on Windows matched or exceeded Edge’s scale of usage on the data the Commission relied on, showing that rivals could offset the pre-installation advantage.

Key takeaways

An undertaking facing potential designation should bear in mind: 

• meeting the thresholds shifts the burden but does not seal the deal; 
• any evidence directed concretely and specifically at rebutting a presumption is permitted in principle (only market-definition and efficiency arguments are excluded); and 
• not all ecosystems comprise important gateways, warranting a case-by-case assessment.