Financialization and sustainable urban planning are now two major components of urban production and landscape change in Western cities. The purpose of this article is to demonstrate how the intervention of financial actors influences urban sustainability in the building of megaprojects, by developing a conceptual framework for analysis and interpretation. This framework aims first to examine the way in which sustainability has been produced by the different actors involved in a real‐life situation, and then to place these interactions in their institutional, spatial and temporal context. Consequently, sustainability is understood as a social construct which is the object of negotiations that have led to the making of institutional arrangements in order to allow the project to be carried through. This framework has been constructed from the financial geography and urban geography literature on ‘finance, the city and sustainability’ and from a case study. The latter looks at the regeneration of a brownfield site to create a shopping and leisure complex that was the biggest in Switzerland and was purchased by financial actors.