Main establishment
The main establishment is, for a controller with establishments in more than one Member State, the place of its central administration in the Union, unless the decisions on the purposes and means of processing are taken in another establishment in the Union which has the power to have them implemented, in which case that other establishment is the main establishment; for a processor with establishments in more than one Member State, it is the place of central administration in the Union or, absent one, the establishment where the main processing activities take place (Art. 4(16) GDPR).
The concept exists to identify the lead supervisory authority under the one-stop-shop mechanism for cross-border processing. Recital 36 and the EDPB Opinion 04/2024 explain that the central administration is presumed to be the main establishment only if it actually takes decisions on purposes and means and has the power to implement them; a letterbox headquarters does not qualify, and the burden of proof lies on the organisation. Where decisions for different processing operations are taken in different Member States, an organisation may have different main establishments for different processing. The EDPB and the lead authority may challenge a designation, as several authorities did in cases involving technology groups that had declared Irish or Luxembourg headquarters.
For international life sciences groups the question is practical: a US sponsor with a Dutch European headquarters and clinical operations in Germany and France will typically have its main establishment in the Netherlands if that is where European decisions on trial data processing are taken, making the Autoriteit Persoonsgegevens its lead authority. Documenting this analysis in the record of processing activities and in group governance charts avoids disputes at the moment of a breach notification or investigation, when the identity of the competent authority must be clear within hours. Groups with no EU establishment have no main establishment and rely instead on their Art. 27 representative.
