The Trump administration is seeking to join Elon Musk’s appeal against a €120 million EU fine of the billionaire’s social media platform X, the latest escalation in the transatlantic clash over Brussels’ efforts to rein in US tech companies.

The US Department of Justice on Thursday filed an application to intervene in a pair of cases brought by Musk and X seeking annulment of the penalty, which will be heard at the EU’s General Court in Luxembourg.

“The European Commission inappropriately attempted to expand its regulatory authority to reach American companies not present or operating within its jurisdiction,” assistant attorney general Brett Shumate said.

“We will not tolerate the European Commission engaging in regulatory over-reach to try and control American engines of innovation and economic growth,” Shumate added.

The European Commission in December last year fined X €120 million for breaking the Digital Services Act, the first such penalty under the bloc’s online safety regime. It accused the platform of breaching its regulations for transparency, providing insufficient access to data and the deceptive design of its blue-tick system for verified accounts.

The DSA, a more aggressive set of rules to police online players, has become a flashpoint between Brussels and US tech companies. Donald Trump’s administration has supported claims by US companies that the EU is unfairly targeting American groups and infringing freedom of speech principles championed by the Maga movement.

Several senior figures of the administration, including US vice-president JD Vance, have criticised the EU’s fining X. Musk is one of the largest donors to President Trump and his favoured Republican candidates ahead of the midterm elections.

In its statement, the DOJ said the DSA had improperly “extended legal scrutiny to Mr Musk himself as a private individual and implicated entirely separate and unrelated American corporate entities under his ownership

The DOJ also asserted that the Commission inappropriately calculated the fine based on the combined global annual revenue of other companies that Musk controlled, rather than what X earned within its jurisdiction.

In March 2025, X was first merged with Musk’s artificial intelligence company xAI, which was subsequently acquired by his rocket maker SpaceX ahead of its public listing in June this year.

SpaceX declined to comment.

Separately, the EU is investigating X for other potential breaches under the DSA, including whether the company has assessed and mitigated risks associated with the integration of its AI chatbot Grok into X for EU users.

Apple is also appealing a €500 million fine imposed under the EU’s related Digital Markets Act for anti-competitive behaviour in its app store.

Trump has railed against the penalties, calling them “overseas extortion” and called them a “form of taxation.” During his first administration, the president unsuccessfully tried to influence Apple’s challenge against a €13 billion Irish tax bill.

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