The private values of 'thickets' and 'fences': towards an updated picture of the use of patents across industries

On the basis of a novel data set of 612 European patents and related inventions from five different industries, it is shown that multiple patents per invention are filed in both discrete and complex technologies. Multivariate analysis of the data suggests that in selected discrete technologies, patent 'fences' may serve to exclude competitors whereas in complex technologies, 'thickets' represent exchange forums for complementary technology. The results expand on traditional views of profitable patent exploitation across industries and elaborate on the most recent findings by Cohen et al. (Cohen, W.M., Nelson, R.R. and Walsh, J.P. (2000) Protecting Their Intellectual Assets: Appropriability Conditions and Why U.S. Manufacturing Firms Patent (or not). Cambridge, MA: NBER.) The analysis suggests that different legislative issues arise from multiple patenting per innovation in complex and discrete technologies depending on the degree of technological complementarity. The results have unexpected policy implications in that they illustrate how patentees could eliminate competition in the form of substitute technologies through fencing. They have wide managerial implications regarding the valuation of patent portfolios and the design of corporate IP strategies.