Fragmented Property Rights and Incentives for R& D

Where product innovation requires several complementary patents, fragmented property rights can limit firms' willingness to invest in R& D. We consider the research intensity in multiple simultaneous R& D contests and how it depends on whether firms already hold relevant patents as well as the availability of an option to invent around. A measure of technological uncertainty is also analyzed. The multiple patent product involves an important hold-up problem that can reduce the overall R& D effort. Invent-around options moderate this problem. We also analyze targeted equilibria in which the aim of R& D can be to hold up a rival.