Firms should be considered as actors that potentially mediate between social movement pressures and policy outcomes. This article shows that at the mining project level, social mobilization can generate important changes in corporate practices toward nearby communities, and that these practices can undermine the cohesion of social movement coalitions advocating for regulatory intervention or reform, thus limiting their ability to make compelling claims on the state. In this way, company interpretations of and responses to protest are an important mediating process that conditions civil society efforts to activate state institutions in their favor. This argument extends recent work on the social foundations of regulation in Latin America by including corporate actors. The article is based on a comparative case study of the Pascua Lama/Veladero mining projects in both Argentina and Chile, using both secondary sources and primary field research. © The Author(s), 2023. Published by Cambridge University Press on behalf of the University of Miami.Social Sciences and Humanities Research Council of Canada, SSHRC; Fondo Nacional de Desarrollo Científico y Tecnológico, FONDECYT, (3200013); Consejo Nacional de Investigaciones Científicas y Técnicas, CONICET; Agencia Nacional de Investigación y Desarrollo, ANID