This paper analyzes selection biases in the project choice of complementary technologies that are used in combination to produce a final product. In the presence of complementary technologies, patents allow innovating firms to hold up rivals who succeed in developing other system components....

This paper develops a theory of patent portfolios in which firms accumulate an enormous amount of related patents in diverse technology fields such that it becomes impractical to develop a new product that with certainty does not inadvertently infringe on other firms’ patent portfolios. We...

This paper analyzes patent pools and their effects on innovation incentives. It is shown that the pro-competitive effects of patent pools for complementary patents naturally extend for dynamic innovation incentives. However, this simple conclusion may not hold if we entertain the possibility...