Elon Musk, owner of social media giant X, and companies of his are calling on the High Court to halt an investigation by the Irish media regulator into whether X’s complaints procedures for EU users comply with the Digital Services Act. An adverse outcome to the investigation by Coimisiún na Meán could mean potential fines of up to 6 per cent of the turnover of any culpable entity, Judge Barry O’Donnell was told.A key issue in the proceedings concerns the identity of the “provider” of the X service in the EU.The regulator had erred in law in believing Musk’s “decisive influence” on companies in the X group should mean that he, with three X companies – X Holdings Corp (XHC), X Internet Unlimited Company (XIUC) and X AI Holdings Corp – are providers of the X service in the EU, senior counsel Declan McGrath, for Musk and XHC, said. The judge on Tuesday began hearing two separate judicial review challenges to Coimisiún na Meán’s investigation, one by Musk and XHC, and a second by XIUC.The investigation, initiated last November but on hold pending the outcome of the cases, concerns whether X contravened provisions of the Digital Services Act dealing with the internal complaint-handling systems operated by larger online platforms. Because X, formerly Twitter, has an average 45 million active users monthly across the EU, it is among various online platforms designated by the European Commission to have additional responsibilities.The regulator’s investigation includes inquiring whether users of the site can appeal X’s decisions not to remove content after they report content they believe breaches X’s terms of service. It also concerns whether complainants are properly informed of the outcome of their reports, of their right to appeal and whether X has an accessible and user-friendly internal complaints mechanism.Lawyers for Musk and XHC got leave last December to challenge the investigation. Among their claims is that the regulator had no jurisdiction to begin the investigation without first determining who provides the X service within the EU. In its separate challenge, XIUC, represented by senior counsel Neil Steen, argues that the “ambiguous” direction grounding the investigation lacks legal certainty and should be declared void. It also alleges breach of fair procedures and transparency requirements and that the notice of investigation failed to provide details of suspected contraventions. The commission rejects the claims and argues the challenges are premature.Opening the first challenge, McGrath argued that Musk, who is based in the US, and XHC are not the provider of X’s “service” in the EU and have no contractual relationship relating to recipients of the service in the EU. They argue XIUC, with an address in Dublin and which is a wholly-owned subsidiary of XHC, provides the X Service to users in the EU. The regulator acted beyond its powers in opening the investigation without determining whether Musk or XHC are relevant intermediary service providers within the terms of the Act, it is argued. The applicants should know whether or not they are providers and, if so, what their legal obligations are, said McGrath. XIUC accepts it is the provider, he said. This was an important issue because the investigation is “criminal in character”, not because of any culpability but because of the potential penalties involved, he said. Fines potentially available in an investigation under the Digital Services Act can amount to 6 per cent of turnover, higher than the 2 per cent of turnover fines potentially available in investigations under the General Data Protection Regulation, he said. At the time the regulator began its investigation, there was a decision by the European Commission that XIUC is provider of the X service in the EU and the regulator cannot go beyond that, he argued. The European Commission later reserved its position regarding whether XIUC is the only provider of the X service in the EU, the court heard. The High Court could make a reference to the European Court of Justice concerning this issue, McGrath said.The hearing, listed for three days, continues on Wednesday.