ABSTRACT
This chapter outlines the importance of studying complex institutional forms which go beyond the state-market dichotomy to solve the problems related to the management both of common resources and of quasi-collective goods and services. Recognizing the institutional dimension of the social and solidarity economy (SSE) means analyzing its participation in the deployment of norms and regulations both at the level of the organization and beyond and so asserting its public dimension, which remains a blind spot in Ostrom's works. Regarding analysis of the forms of ownership of the SSE and commons, institutional diversity is impossible to ignore, and it calls into question both the classic state-market dichotomy and the classic definition of property. In the case of common resources, the collective interest is essentially the interest of a group, the appropriators, making it more of a mutual interest, even if the sustainable management of a resource includes a general interest dimension.
