In his Opinion of 15 October 2026 in ByteDance v Commission (C‑627/24 P), Advocate General Andrea Biondi addresses the requirements for rebutting the presumptions underlying a DMA gatekeeper designation. He also disagrees with the General Court’s assessment of ByteDance’s right to be heard and proposes substituting the grounds of its judgment in this respect.
In September 2023, the European Commission designated ByteDance as a gatekeeper for its online social networking service TikTok. ByteDance challenged the designation, arguing that it did not meet the qualitative requirements of Article 3(1) DMA despite exceeding the quantitative thresholds.
The General Court dismissed the action in its judgment of 17 July 2024 (T‑1077/23). ByteDance subsequently appealed to the Court of Justice.
Rebutting the presumptions under Article 3 DMA
Article 3(2) DMA establishes quantitative thresholds giving rise to presumptions that an undertaking meets the three qualitative criteria for gatekeeper designation under Article 3(1) DMA.
Under Article 3(5) DMA, undertakings may submit arguments demonstrating that, exceptionally, they do not satisfy those qualitative requirements despite meeting the quantitative thresholds.
The Advocate General considers that rebutting these presumptions requires a high degree of plausibility. Mere doubts about whether the qualitative requirements are met are insufficient. The undertaking must submit sufficiently convincing arguments capable of clearly calling the presumptions into question.
However, it is not required to establish conclusively at this stage that the qualitative criteria are not satisfied. Otherwise, the distinction between rebutting the presumptions and conducting a market investigation would lose much of its significance.
The Advocate General also addresses the Commission’s discretion under Article 3(5) DMA. Where sufficiently substantiated arguments clearly rebut the presumptions, the Commission must, in principle, initiate a market investigation rather than simply reject those arguments.
In the present case, however, the Advocate General considers that ByteDance’s arguments did not meet the required standard.
In particular, the fact that users engage in multihoming, using TikTok alongside competing social networking services, does not necessarily mean that TikTok cannot constitute an important gateway for business users to reach end users within the meaning of Article 3(1)(b) DMA.
Similarly, the absence of an extensive digital ecosystem does not, in itself, preclude a finding that a platform constitutes an important gateway.
The right to be heard: Substitution of the General Court’s grounds
A second important aspect of the Opinion concerns the procedural rights of undertakings during the designation procedure.
The General Court had found that the Commission infringed ByteDance’s right to be heard in certain respects. Nevertheless, it dismissed the action because those procedural irregularities could not have affected the outcome of the procedure.
The Advocate General disagrees with the finding of a procedural infringement.
Although the right to be heard under Article 41(2)(a) of the Charter of Fundamental Rights applies, the Commission is not generally required to give an undertaking a further opportunity to comment on its assessment of arguments and evidence submitted by that undertaking itself.
The Advocate General therefore proposes substituting the grounds of the General Court’s judgment on this issue, while maintaining the dismissal of ByteDance’s action.
This distinction has practical consequences for future designation procedures.
If the Court of Justice follows the Advocate General’s approach, undertakings seeking to rebut the presumptions under Article 3 DMA will need to present their arguments and supporting evidence as comprehensively as possible at an early stage of the administrative procedure.
They cannot generally expect a further opportunity to respond to the Commission’s assessment of their submissions before the designation decision is adopted. This does not, however, exclude additional procedural safeguards where the Commission relies on new evidence obtained through its own investigative measures.
The Opinion thus combines a demanding standard for rebutting the quantitative presumptions with relatively limited opportunities to supplement submissions in response to the Commission’s assessment.
Implications for future DMA gatekeeper designations
The Opinion confirms the importance of the quantitative thresholds in the DMA’s designation mechanism. Although the presumptions remain rebuttable, undertakings face substantial requirements when challenging their application.
At the same time, the Commission’s discretion is not unlimited. Where the arguments submitted clearly rebut the presumptions, the Commission must generally proceed to a market investigation.
The proposed substitution of grounds is particularly relevant to the conduct of designation proceedings. It would clarify that the Commission is not generally obliged to consult an undertaking again merely because it reaches an assessment of evidence that the undertaking itself submitted.
The Court of Justice has yet to deliver its judgment. The Advocate General’s Opinion is not binding.
