We investigate incidence and evolution of patent thickets. Our empirical analysis is based on a theoretical model of … patenting in complex and discrete technologies. The model captures how competition for patent portfolios and complementarity of … patents affect patenting incentives. We show that lower technological opportunities increase patenting incentives in complex …

states, Prussia granted patents more restrictively by setting higher novelty requirements. Though, patent fees were much … patent-regime change on world-fair exhibits per capita, which we use as a proxy for non-patented innovation. We interpret …This paper analyzes the consequences of radical patent-regime change by exploiting a natural experiment: the forced …