A consensus is emerging around the world about the need for policymakers to address certain characteristics and competitive tendencies that are generated by digital platforms or digital ecosystems, with a view to reforming the public policy instruments currently in place so that they are fit for the digital age. The paper starts by reviewing the relevant precedents under EU competition law and economic regulation upon which this reform could be based. The paper then puts forward recommendations to adapt competition rules, in particular as regards the determination of market power (e.g., by better taking into account the effects of ecosystems, the impact of potential competition and the role of innovation) and the application of theories of harm (i.e. by focusing on leveraging and envelopment behaviour, access to key innovation capabilities, discrimination and self-preferencing and the violation of normative regulatory principles). The paper then proceeds to propose a cumulative 'three criteria test' to determine the types of digital platforms upon which competition rules, and possibly complementary regulation, should focus. These three criteria require an assessment of: (i) the existence of market structures which are highly concentrated and non-contestable; (ii) the presence of digital gatekeepers which act as unavoidable trading partners; (iii) and, for the purposes of ex ante regulation, the lack of effectiveness of competition rules to address the identified problems in the market. The paper also considers the types of remedies that could be imposed on those identified digital platforms, including: interoperability and access to key innovation capabilities such as data; the prohibition of anti-competitive discrimination; and the facilitation of consumer switching. Given the rapid evolution of technology and market uncertainty, consideration should be given as to whether these remedies should be imposed in a participatory manner with the industry stakeholders directly affected by the measures. Finally, the paper deals with a number of procedural and institutional issues raised by the adoption of such a legal standard, proposingto adapt existing antitrust guidelines, to extend the power of DG Competition to conduct fully fledged market investigations (as is the case in the UK and Australia) and possibly to work closely with National Regulatory Agencies, coordination with whom at EU level arguably needs to be strengthened.