This chapter analyses the roles and activities of multinational companies (MNCs) in an entrepreneurial ecosystem (EE) and local start-up incubation. Drawing from literature regarding EEs and incubation policy, we present an example of a type of intervention under-theorized to date: incubation efforts stemming from MNCs rather than government or universities. Presenting the case of Microsoft Innovation Centers (MIC) in Brazil, we explore how collaboration is organized between interdependent actors to provide start-up incubation and foster ecosystem development. We consider both the benefits for the MNC and for the regional actors, and some potential compromises or downsides when MNCs step into the sphere usually occupied by public institutions. Through collaboration with local actors, MNCs may tap into business ecosystems and link regional resources to their own R & D activities at an international scale, while increasing competences in the local community.