Irish data regulator DPC may resume its investigation into Facebook.
The privacy watchdog demanded that the social media platform stop transferring user data from the European Union to the United States, but Facebook appealed that decision to the Irish Supreme Court.
According to the regulator, personal data may be less well protected in the United States than in the European Union, so that it cannot be exchanged just like that.
However, Facebook believes that "a lack of secure international data transfer is harmful to the European economy".
The company also wants regulators to look for a long-term solution.
The Supreme Court did not agree.
According to the Irish court, no valid reasons have been put forward by Facebook to contest the decision of the regulator.
According to the judge, nothing was wrong with the privacy watchdog's working method.
According to the court, the investigation by the supervisory authority may therefore continue.
Facebook may face a large fine if it appears that the rules have been broken.
The Irish regulator is the primary privacy authority for Facebook and many other US tech giants with their European base in Ireland, such as Apple and Google. That means that the final decision can also set the course for data transfers for many other companies under Irish supervision.