Three-party business models in which a platform operator intermediates between a supplier providing a service and a customer buying a service have become an important part of our daily lives. For purposes of European Value Added Tax (VAT), each transaction occurring as part of a three-party business model must be attributed to a ‘taxable’ person responsible for the VAT. Generally, suppliers may provide their services for VAT purposes as proprietary traders, undisclosed agents or disclosed agents, with varying VAT consequences. While there is little explicit case law specifying how to identify the two forms of agency, this article provides a framework for a distinction by building upon the case law of the European Court of Justice (ECJ), taking into consideration the economic and commercial reality of each case and placing particular emphasis on the view of the average consumer. To contribute to a more uniform approach in attributing supplies in three-party, platform-based business models, specifically, this article develops indicators for assessing the relevant facts and ascertaining the economic reality of a case. Lastly, this article provides a method for differentiating agents from providers of electronically supplied services under current EU VAT law.