The European Commission (EC) has published its draft Digital Markets Act (DMA), which will introduce broad reforms to the application of EU competition law to ‘gatekeepers’ in the digital sector. The proposals set out in-principle criteria for companies that offer ‘core platform services’, which, if met, raise the rebuttable presumption that the company is a gatekeeper. Companies that meet the criteria will either need to prove to the EC that they are not gatekeepers or will need to abide by specific ‘dos and don’ts’, with significant fines for non-compliance, and the possibility of repeat offenders being required to divest parts of their business. The DMA would also allow the EC to conduct market investigations to enable it to keep the gatekeeper criteria and ‘dos and don’ts’ updated dynamically and to design remedies to tackle systematic infringements of the DMA rules. The DMA was published alongside a draft Digital Services Act (DSA), which has a wider scope (applying to all digital services that connect consumers to goods, services, or content) and will, if adopted, introduce new obligations relating to such issues as illegal content, transparency and traceability of business users. Our initial overview sets out the key elements of both proposals. This article looks in more detail at how the DMA will work, and its likely impact.