Combining both interview data and empirical analyses at the patent and firm levels, we explore the value-appropriation and value-creation implications of R&D collaboration resulting in the co-ownership of intellectual property (i.e. co-patents). We make an explicit distinction between three different types of co-patenting partners: intra-industry partners, inter-industry partners, and universities. Our findings indicate that the value-appropriation challenges of IP sharing are clearly evident with intra-industry co-patenting, where partners are more likely to encounter overlapping exploitation domains. Co-patenting with universities is associated with higher market value, since appropriation challenges are unlikely to play a role and collab...