The power of online platforms was established on personal data, which the European Union first sought to curb from the perspective of protecting natural persons with the provisions of the General Data Protection Regulation (GDPR), but also aimed to include the free flow of this data among its objectives. Exploiting the uncertainties related to the application of the GDPR and its not always effective enforcement, platforms have gained such market dominance through big data management and unfair market practices that they are capable of abusing it. Therefore, the experiences of traditional competition law investigations and merger control investigations have prompted the European Union to regulate these ex ante with targeted regulations. In fact, the regulatory need to address market competition concerning the handling of personal (and non-personal) data on platforms gave rise to platform regulations, many of whose provisions have grown out of the GDPR. This study examines the role of personal data and data protection in platform regulations.