Tracking patent transfers in different European countries: methods and a first application to medical technologies

Drawing on more than half a million granted patents in all technological sectors filed at EPO between 1998 and 2012 we gather information on 300,000 inscriptions affecting changes in their ownership at the EPO and top national registers (France, Germany, Switzerland, Spain). After grouping parallel legal events in different European validation countries, we find that more than 30% of EPO patents in all fields change ownership at least once. For the field of medical technologies, we exploit additional information on corporate structures to further distinguish between “intragroup” and “bare” changes of ownership thanks. Our results indicate that more than two-thirds of the transfers happen “intragroup”, that is between related corporate entities. Using regressions analyses, we finally explore and discuss relations between the occurrence and types of these transfers of patent and proxies for patent quality.