We investigate incidence and evolution of patent thickets. A theoretical model of patenting encompassing complex and discrete technologies is introduced. It is shown that decreased technological opportunities increase patenting incentives in complex technologies. This effect gets stronger as complexity grows. In contrast, lower technological opportunities reduce patenting incentives in discrete technologies. We also analyze under which conditions greater complexity increases patenting incentives in complex technologies. A new measure of technological complexity is proposed that captures the density of patent thickets. Additionally, measures of fragmentation and technological opportunities are constructed exploiting European patent citations. We employ a panel capturing patenting behaviour of 2074 firms in 30 technology areas over 15 years. GMM estimation results show that patenting conforms to our theoretical model. The results indicate that patent thickets exist in 9 of the 30 technology areas. Decreasing technological opportunities are a surprisingly strong driver of patent thicket growth.
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Paper provided by C.E.P.R. Discussion Papers in its series CEPR Discussion Papers with number
6900.