The leveraging of inter-firm networks is increasingly considered to be a strategic resource that can potentially be shaped by managerial action. In recent years, scholars have turned to the concept of social capital to understand how the transfer of knowledge occurs within and across firms. However, this has resulted in an overstretching of the social capital concept. The aim of this paper is to refine and add specificity to the current broad application of the social capital concept. It is argued that although the social capital concept explains investments in networks based on a network logic relating to sociability and socialization, it does not explain investments in networks based on a logic relating to economic expectations. These expectations result in network participation that is more calculative than networks containing social capital. The paper introduces the notion of ‘network capital’ to explain the resources contained within inter-firm networks that do not necessarily equate with the type of trust and obligations associated with social capital. Network capital is defined as an investment in calculative relations through which firms gain access to knowledge to enhance expected economic returns. It is argued that while network capital can be strategically managed, particularly to influence knowledge flow, the nature of social capital is such that it is very difficult to manage. It is concluded that the network capital–social capital framework opens a number of avenues in terms of future research, especially in relation to the extended resource-based view of the firm and theories of open innovation.