The US Justice Department wants to join Elon Musk and X’s legal challenge against the European Commission’s €120 million fine, arguing that Brussels exceeded its authority over an American-owned company. The intervention could influence how the EU regulates large US-based digital platforms and whether it can hold company owners and related businesses jointly liable.

The fine, issued under the Digital Services Act, concerns X’s paid blue checkmarks, advertising database and restrictions on researchers accessing public data. The Commission said the verification system could mislead users, while the US argues that the penalty improperly relied on Musk’s wider corporate group and worldwide turnover; the issues are separate from UK investigations into illegal hate speech and terrorist content.