This document discusses various approaches to financing social innovation. It begins by outlining a framework with 5 stages of financing: 1) prompts, 2) proposals, 3) prototypes, 4) sustaining, and 5) scaling. It then examines different types of funding that are appropriate for each stage based on risk and impact. Examples of funding mechanisms discussed include grants, venture philanthropy, impact investing, social impact bonds, and preventative investment at the city level. The document also explores questions around the degree of competition, mobilizing procurement, and examples from the UK like the Peterborough Social Impact Bond and Greater Manchester preventative investment program.