Role of the State’s Prosecution Office as a promoter of the payment for ecosystem services mechanism: case of the Oásis Brumadinho project in Brazil

“Payment for ecosystem services” (PES) schemes have been introduced worldwide as an instrument to support the participation of multiple actors through an organizational arrangement. In Brazil, Minas Gerais State’s Prosecution Office (MPMG—Ministério Público de Minas Gerais, in Portuguese) acted as a pioneer in channeling resources from Deferred Prosecution Agreements (TACs—Termo de Ajustamento de Conduta, in Portuguese) to financially enable a PES project’s implementation. This is the first study to have analyzed the performance of the MPMG as a prominent actor in the institutional arrangement related to this project. The research mobilizes the notion of institutional design as proposed by Corbera, et al. (Ecol Econ 68:743–761, 2009), which establishes that, for the long-term viability of PES schemes, different institutional actors have fundamental roles to play, specially dedicated to the financial sustainability of the schemes. This research involved related documents’ analysis and a state-of-the-art review of the origin and implementation of the Oásis Brumadinho project in the Brazilian State of Minas Gerais. An analysis of the institutional arrangement of the Oásis Brumadinho project showed that the role of the State’s Prosecution Office was crucial in making the PES feasible in terms of transaction costs. Our reflections on alternatives to finance PES projects will be useful for future cases, especially the new legal provision of the National Policy on Payment for Environmental Services at the federal level. Overall, this study furthers our understanding of the role played by the State’s Prosecution Office and sheds light on the possibility of using TAC resources as an economic alternative to enable the implementation of PES frameworks in other locations in Brazil.