TikTok owner ByteDance lost its court challenge on Wednesday against its designation as a gatekeeper under the EU's landmark Digital Markets Act (DMA), marking a victory for EU antitrust regulators aiming to curb Big Tech's power.

The DMA mandates gatekeepers to ensure their messaging apps can interoperate with rivals, allow users to choose which apps to pre-install on their devices, and prohibits them from favoring their own services over competitors'.

ByteDance contended that its gatekeeper status could undermine the DMA's objective by protecting established companies from newer entrants like TikTok, which lacks a dominant position. However, the Luxembourg-based General Court dismissed ByteDance's challenge, siding with the European Commission.

"The Commission was fully entitled to consider that ByteDance was a gatekeeper," the judges stated, noting that ByteDance had not sufficiently substantiated its arguments.

The Court highlighted that ByteDance met the DMA's quantitative thresholds concerning its global market value, the number of TikTok users within the EU, and the duration for which these user thresholds had been met.

The judges also noted TikTok's rapid rise in popularity, which has positioned it alongside rivals Meta Platforms and Alphabet. "It had rapidly consolidated its position, and even strengthened that position over the following years, despite the launch of competing services such as Reels and Shorts, to the point of reaching, in a short time, half the size, in terms of number of users within the European Union, of Facebook and of Instagram," the judges explained.