Firms and their networks

•Firms are not only means of production, finance, labor, contracts. Firms' networks are part of the firm.•Workers or CEOs and their social relations, suppliers are examples of such networks.•These networks may enhance firm's productivity but they may also have a detrimental effect on governance.

I present a summary of virtually ten years of research using a simple point of view in which firms among other assets, use networks to perform a wealth of tasks: hiring, firing, buying from suppliers, governing the firm … Access to such networks is rarely included when financiers assess the value of a firm. This line of research suggests that they should.