This paper examines the evolution of the institutional logic of public finance in Brazil, adopting both an historical time frame and a short time frame of recent reforms. We find that a bureaucratic logic of budgeting at the level of the organizational field has blended historically with a political logic of patrimonial power at the societal level to form a succession of hybrid institutions. Adopting a shorter-term perspective, we observe the processes by which hybridization occurs in response to reforms for fiscal responsibility and accruals reporting. Our analysis reveals two pathways to hybridization: by the assimilation of compatible institutional logics and by the accommodation of contradictory logics. We explain reform outcomes as the product of the agency of actors performing social roles across the organizational field. These generate a ‘package’ in which the accommodation of change in some respects is facilitated by the persistence of operational routines in other respects. In reviewing our contribution, we propose that more attention should be given to studies at the level of the organizational field which reveal agency as the product of the structural position of role-holders to complement studies of specific organizations which tend to suggest strategic agency.