Europe’s top court on Tuesday affirmed the power of national data regulators to pursue cases against major tech companies even if they have their headquarters elsewhere on the continent.

The EU Court of Justice’s ruling means that Facebook, Google, Twitter and Apple — all of which have their European bases in Ireland — may face investigations from more bloc members under certain circumstances.

The decision came in a case over a probe by Belgian authorities against Facebook claiming that the social media giant did not adequately notify users about data collection and use.