Proposals for slowing climate change by reflecting sunlight back to space, known as solar geoengineering (SG), are gaining traction in climate policy. Given SG’s capacity to slow warming without reducing carbon emissions, prominent criticism suggests that it will enable fossil fueled business-as-usual. This assessment is not without merit, yet the primary funders of SG research do not emanate from fossil capital. We analyze sources of funding for SG research globally, finding close ties to mostly US financial and technological capital as well as a number of billionaire philanthropists. These corporate sectors and associated philanthropies comprise part of ‘climate capital’ – the fraction of the capitalist class nominally aligned with climate action. We argue that SG is being positioned as a tactic for enabling incremental, market-driven decarbonization, explore key institutions advocating this approach in US climate policy, and conclude that SG is poised to serve as a tool for class compromise between fossil and climate capital.