Elon Musk's X has been accused of breaching content rules set out in the EU's Digital Services Act (DSA).
On Friday (12.07.24) it was ruled that the billionaire businessman's micro-blogging site had failed to provide a searchable and reliable advertisement repository.
The company also finds itself in hot water for not giving researchers access to its public data.
X could be forced to shelve out 6 per cent of its global turnover and make changes to its operation - unless they can prove otherwise.
EU industry chief Thierry Breton commented: "X has now the right of defence — but if our view is confirmed we will impose fines and require significant changes."
Other tech giants under investigation include ByteDance's TikTok, AliExpress and Meta Platforms.
In March, it was revealed that the EU was investigating Apple, Meta and Google's compliance with the Digital Markets Act.
Speaking at a press conference in Brussels, Belgium, EU antitrust boss Margrethe Vestager said: "We suspect that the suggested solutions put forward by the three companies do not fully comply with the DMA.
"We will now investigate the companies' compliance with the DMA, to ensure open and contestable digital markets in Europe."
It came after the EU fined Apple €1.8 billion (£1.5 billion) for breaking competition laws over music streaming.
Spotify prompted the response after slamming its rival for its control of payments and 30 per cent fee on the App Store.
Vestager accused Apple of preventing "developers from informing consumers about alternative, cheaper music services available outside of the Apple ecosystem."
She declared: "This is illegal under EU antitrust rules."
Apple subsequently filed an appeal.
Vestager recently said: "We have a number of Apple issues; I find them very serious.
"I was very surprised that we would have such suspicions of Apple being non-compliant."
