(36) The main organizational unit of a controller in the Union should be the location of its central administration in the Union, unless decisions on the purposes and means of processing personal data are made in another organizational unit of the controller in the Union, in which case the latter organizational unit should be considered the main organizational unit. The main organizational unit of the controller in the Union should be determined on the basis of objective criteria; it should mean effective and actual management through stable structures involving the most important decisions on the purposes and means of processing. This criterion should not depend on whether the processing of personal data takes place at this location. The presence and use of technical means and technology for processing personal data or for processing activities do not in themselves constitute the main organizational unit, so they are not criteria for determining it. The main organizational unit of a processor should be the place where its central administration in the Union is located, or if it does not have a central administration in the Union, the place where the main processing activities in the Union take place. If the case involves both a controller and a processor, the relevant lead supervisory authority should remain the supervisory authority of the Member State where the controller has its main organizational unit, but the supervisory authority of the processor should be recognized as the supervisory authority concerned and should participate in the cooperation procedure provided for in this Regulation. The supervisory authorities of the Member State(s) where the processor has one or more organizational units should not be considered as the supervisory authorities concerned in any case if the draft decision only concerns the controller. If the processing is carried out by a group of companies, the main organizational unit of the controlling company should be considered its main organizational unit, unless the purpose and means of processing are determined by another company.