Digital platform research focuses on the mechanisms in digital platform ecosystems and the dynamics between platform owners, complementors, and end-users. Recent studies begin looking beyond the boundaries of narrow platform ecosystems. The development of the European Union’s Digital Markets Act (DMA) is a revelatory case to study this wider perspective of ecosystems and its dynamics. Hundreds of actors participated in discourses on the regulation, which aims to regulate so-called gatekeeper platforms that are alleged to be powerful, unfair to platform users, and incontestable for competitors. By means of a critical discourse analysis, we coded 1720 contributions on the proposed and adopted DMA between June 2020 and July 2022. We identify 72 positions and 16 narratives along 5 discourses. Our study creates a better understanding of a wider perspective of platform ecosystem structure that goes beyond the triangle of platform owner, complementors, and end users.