Financialization is promoted by alliances of multilateral 'development' organizations, national governments and owners and institutions of private capital. In the healthcare sector, the leveraging of private sources of finance is widely argued as necessary to achieve the Sustainable Development Goal 3 target of universal health coverage. Employing social science perspectives on financialization, the authors of this article contend that this is a new phase of capital formation. The article traces the antecedents, institutions, instruments and ideas that facilitated the penetration of private capital in this sector, and the emergence of new asset classes that distinguish it. The authors argue that this deepening of financialization represents a fundamental shift in the organizing principles for healthcare systems, with negative implications for health and equality.