Upon the deep and open sea: The DMA and ne bis in idem

As the DMA begins to take effect, some procedural issues arising from the complementary nature of the relationship between this act and competition law must be addressed. As is well known, the DMA applies ex ante, while competition law applies ex post. However, the same market conduct may lead to the duplication of proceedings and penalties. Therefore, the question arises as to what kind of protection the ne bis in idem principle can provide, and, most importantly, how it would be possible to utilise the ECJ’s case law on parallel proceedings. These topics are addressed in this Chapter.