This article demonstrates the inner relationship between gatekeepers and their complementors and the impact of information sharing on the overall market competition intensity and the economic surplus allocation. Several competition law-based cases are grounded on the incompleteness and information asymmetry in which complementors have to make their decisions. In this article, the situation of the complementors is all the more unfavourable when their partnership with the gatekeeper is a durable one. We use a game theory-based model to explain this trajectory. The informational imperfections undermine the bargaining power of the complementors and raise the potential cost of the exit option out of the ecosystem. In this perspective, we envisage regulatory remedies as data portability as proposed by the E.U. Commission Digital Markets Act.