Trust, trustworthiness and ethical norms of reciprocity and cooperation have been receiving more and more attention in economic analysis. In particular, two concepts have been widely used in order to study the socio-economic effects of these factors: the concept of social capital (hereafter also SC) and of corporate social responsibility (hereafter also CSR). Even though SC and CSR seem to be linked by many common elements related to the quality and quantity of social relations between agents, their relationship has not been deeply investigated yet. This paper is aimed at shedding light on some aspects of this relationship, in particular, by investigating the idea of a virtuous circle, between the level of SC and the implementation of CSR practices, that fosters socio-economic development by generating social inclusion and social networks based on trust and trustworthiness. Following the literature on SC that stresses its multidimensional character (e.g. Paldam 2000), we consider two dimensions of this notion. Starting from the distinction introduced by Uphoff (1999), we take into account a cognitive and a structural idea of SC. The first one essentially refers to the dispositional characters of agents that affect their propensity to behave in different ways. The latter refers to social networks connecting agents. With regard to the concept of CSR, we adopt a contractarian approach and consider CSR as an extended model of corporate governance, based on the fiduciary duties owed to all the firm's stakeholders. Among stakeholders, we distinguish between strong and weak stakeholders. Both these two categories have made specific investments in the firm. However, strong stakeholders are precious for the firm because they bring in strategic assets. They are, for example, skilled workers or institutional investors. On the contrary, weak stakeholders do not bring strategic assets into the firm and firms have material incentives at defecting in the relationship with them. They are, for example, unskilled workers. Considering the notions of cognitive and structural SC and a contractarian approach to CSR, we show that: a) the level of cognitive SC plays a key role in inducing the firm to adopt and observe CSR practices that respect all the stakeholders; b) the decision of adopting formal instruments of CSR contributes to create cognitive SC that is endogenously determined in the model; c) the level of cognitive SC and the decision of adopting CSR practices creates structural SC in terms of a long term relationship between the firm and the weak and strong stakeholders.
