This paper analyses how the factors breadth of content offerings, boundary resources, and exclusive content explain complementor participation in platform-based ecosystems, in the context of video game consoles. Fixed effects regressions on a panel comprising two generations of consoles across six platforms show that the breadth of content offerings positively affects complementor participation. We find that breadth of content offerings, but not boundary resources and exclusive content, are positively related to complementor participation. When studied in one model, breadth of content offerings dominates the relationship. Our results show how complementor ecosystems can be orchestrated to proliferate a variety of complementary product offerings.@en