Kirk Ludwig presents a philosophical account of institutional action, such as action by corporations and nation states, arguing that it can be understood exhaustively in terms of the agency of individuals and concepts constructed out of materials that are already at play in our understanding of individual action. He thus argues for a strong form of methodological individualism. The book provides a new account of the logical form of grammatically singular group actionsentences (e.g. 'Company laid off 10,000 workers'), and features new analyses of the concepts of a constitutive rule, status function, status role, collective acceptance, and proxy agency. He also provides an analysis of the structure of corporate action, including the status of corporations aslegal persons, and of the nature of state action in relation to its citizens. This is the companion volume to From Individual to Plural Agency (OUP 2016), extending the multiple-agents account of collective action set out in the earlier volume.