The main partner of an EWC is always the central management of the company. In case the central management/headquarters are situated outside the EU or EEA (for example, in the USA) the central management shall be represented by a designated agent who is responsible for all issues concerning the EWC (or its establishment).
In the absence of such a representative of the central management the management of the establishment (or group undertaking) employing the largest number of employees in any Member State is considered the agent of the central management located outside the EU/EEA and hence has all the consequent responsibilities.