Public–private partnerships (PPPs) have reshaped the institutional structure of global governance. They have advanced collaboration on core issues such as health, clean energy, the rights of women and children, and access to infrastructure, among others. But which actors create and finance public–private partnerships in global governance to advance such objectives? What are the implications of the agency behind such collaboration for influencing the global agenda on sustainable development? While some scholars and advocacy groups see the growing role of private actors as a powershift away from public institutions, others argue that such arrangements tend to be complementary to public mandates and indeed may provide a new means for international institutions to pursue such mandates. The article probes this debate by analyzing the type of actors that finance global health partnerships, an area in which the influence of hybrid initiatives is particularly prominent. It reveals that public financing remains a core and necessary condition for the emergence and functioning of PPPs. The growing share of private financing, nonetheless, has important implications for shaping partnerships agendas and steering global health and sustainability governance. Rather than a powershift or abdication of responsibilities by the state, there is rather a tendency of deliberate diffusion of power by donors toward hybrid structures.