The commercialisation of the public sector research base, and in particular academic research, has been a continuing preoccupation among policy makers around the world. Empirically, these issues are explored in the management of intellectual property in university spin-offs (USOs) that emerge through both informal and formal linkages with universities across three sectors. The paper utilises a recently developed methodology to map knowledge flows as well as linkages between organisations. This enables us to examine the exchange of knowledge in commercial and academic networks and the implications of changes in the sponsorship, ownership, and proprietary status of knowledge for these patterns of exchange. It is argued that some of the most important points of tension between universities and the firms studied derive from misconceptions in the value of intellectual property rights.