On October 15, 2026, the Advocate General’s opinion was delivered in ByteDance’s appeal to the Court of Justice against the General Court’s 2024 judgment upholding the Commission’s decision to designate it as a gatekeeper under the DMA for its TikTok core platform service. This is the first DMA case to reach the Court of Justice. The Advocate General’s opinion is meant to guide the Court’s decision-making but is not binding. The judgment is expected at a later date.

In summary, the Advocate General held that the standard of proof is high for undertakings meeting the quantitative thresholds to call into question the presumptions. The undertaking must show with a “high degree of plausibility” that it does not meet the qualitative criteria set out in Art 3(2) DMA. The arguments set out for this purpose must be “genuinely compelling, with no easily identifiable weaknesses in their capacity to rebut the presumption”. The Opinion holds that ByteDance was unable to demonstrate any manifest errors in the General Court’s finding that ByteDance did not discharge this burden. According to the Advocate General, the evidence ByteDance adduced in its rebuttal case was insufficiently substantiated to warrant outright non-designation or the opening of a market investigation.  

Link to Background – EC Decision and General Court Ruling Background – EC Decision and General Court Ruling

The Commission designated ByteDance as a gatekeeper for TikTok in September 2023, finding that ByteDance met the DMA’s quantitative thresholds and that its rebuttal arguments (including reliance on limited EU turnover) were not sufficiently substantiated to manifestly call those presumptions into question.

The General Court dismissed ByteDance’s annulment action in July 2024. While it helpfully confirmed that the types of evidence a presumed gatekeeper can adduce to contest designation include qualitative evidence and are not limited to quantitative data, it imposed a very high burden of proof. It indicated that this burden cannot be discharge by presenting “doubts” or “prima facie” evidence, but that the arguments put forward must be sufficiently substantiated to manifestly call into question the presumption. On this basis it ruled that the evidence ByteDance put forward during the administrative proceedings was insufficient:

  • On the “significant impact on the internal market criterion”, the General Court held that the market-value threshold looks at global fair market value with no distinction as to geographic origin, because the origin of that value has no bearing on ByteDance’s ability to use it to strengthen its EU position. It was for ByteDance, not the Commission, to prove that cultural or regulatory barriers prevented it from leveraging that value in the EU — a case that TikTok was unable to make out given its rapid growth in the EU. The General Court found that the Commission had erroneously dismissed ByteDance’s low EU turnover as simply “irrelevant” once the (alternative) global market value threshold was met. The General Court found that turnover can still carry real evidential weight in the qualitative rebuttal analysis (even if the market cap threshold is met), but held that it was ultimately immaterial to the outcome on ByteDance’s facts, since other evidence of EU monetisation potential still supported designation.
  • On the evidence presented by ByteDance relating to the “important gateway” criterion (including lack of lock-in due to significant multi-homing and lack of an ecosystem, limited scale compared to other players, network effects, limited business dependency and significant interoperability), the General Court found the evidence presented was insufficient to call into question the presumptions and that being a “challenger” and a “gatekeeper” are not mutually exclusive: a business which started as a challenger in 2018 could become a gatekeeper within a few years.

ByteDance appealed to the Court of Justice.

Link to Advocate General Opinion Advocate General Opinion

The opinion is notable on three fronts:

  • High evidentiary bar. The Advocate General confirmed that arguments and evidence must be “genuinely compelling, with no easily identifiable weaknesses” to manifestly call a presumption into question, since mere doubt-casting would otherwise force a market investigation in every case. That said, a company does not have to prove conclusively, at this stage, that it is not a gatekeeper, and the Commission must investigate once a company’s arguments do manifestly call the presumption into question.
  • Important gateway arguments rejected. The Advocate General found that ByteDance failed to demonstrate an error in the General Court’s assessment of the evidence presented by ByteDance on the “important gateway” criterion (including lack of an ecosystem, network effects, user lock-in, multi-homing, business dependency, intensity of use, and relative scale). On relative size specifically, the Advocate General also agreed with the General Court’s finding that new scale-comparison evidence ByteDance introduced for the first time before the General Court — including fair market value comparisons against other platforms, a competitor launch-date timeline, and “copycat” claims — was correctly excluded as inadmissible because it had not been raised with the Commission during the notification stage, and that it was ByteDance’s own choice to compare TikTok only to Facebook and Instagram rather than to the wider pool of competitors it later relied on, having provided no data on that wider comparison at the time. One interesting side-comment the Advocate General made is that the elements considered in a rebuttal case can vary depending on the type of CPS, as distinct services may “operate differently and arguments of different sorts might be used to challenge the applicable presumptions”, emphasising the need for a case-by-case assessment and the need for the Commission to be open to different types of evidence.
  • Right to be heard. The Advocate General indicated that the Commission did not infringe ByteDance’s rights to be heard, as the Commission was not required in the first place to communicate its provisional assessments to the undertaking before adopting a presumption-based designation decision, even where the undertaking had presented a rebuttal case under Art. 3(5) DMA.

Link to Key Takeaways Key Takeaways

While the Opinion is not binding, it may foreshadow that a high standard for the purpose of rebutting the gatekeeper presumption will be endorsed by the Court. Regardless of the exact standard eventually found by the Court of Justice, it will remain crucial for presumed gatekeepers to present rebuttal arguments during the administrative phase that are sufficiently compelling, well substantiated and concrete.

While it is encouraging that the Advocate General confirmed the Commission must engage in a case-by-case assessment and take account of different types of evidence, the burden is on the presumed gatekeeper to determine which evidence is most relevant. The ByteDance experience shows that presumed gatekeepers cannot necessarily count on a genuine steer or dialogue with the Commission in this regard. This would be exacerbated if the Commission were to scrap its practice of communicating its preliminary findings in advance of designation (if the Court confirms, in line with the Opinion, that it is not required to do so).

All this reinforces the importance for presumed gatekeepers of building a thorough and well-evidenced record for their engagement with the Commission, particularly where they wish to raise arguments around comparative size compared to other players, multi-homing, lack of an ecosystem, lack of network effects or user lock-in, business dependency, and geographic origin of scale and turnover.