Fixed establishment (FE) is one of the institutions of the EU value added tax system; its structure is essential to correctly determine the right tax jurisdiction of an EU Member State for the purpose of VAT settlement in situations of cross-border provision of services. However, the legal structure of a FE adopted by the EU legislator (and, consequently, adapted to national legislation of the Member States) causes uncertainty when it comes to its interpretation. In the absence of unambiguously defined conditions in EU law to consider a specific presence and activity of an enterprise to be a FE, interpretation rules contained in judicial decisions issued by the Court of Justice of the EU play an important role. Among attempts made by the CJEU to clarify the ‘blur areas’ resulting from the dynamics of modern business processes, one of the most interesting ones is the possibility of considering a subsidiary to be a fixed establishment for a parent company. The purpose of this paper is to analyse legal and economic factors, the fulfilment of which may constitute a condition for considering a subsidiary to be a fixed establishment for a parent company, with particular emphasis on the ruling of the Court of Justice of 7 May 2020 in the Dong Yang case (C-547/18).