Spinoffs and the Mobility of U.S. Merchant Semiconductor Inventors

Data on assignees of patenters are used to analyze the mobility of semiconductor inventors. A model of the entry and staffing of spinoffs of incumbent producers is developed to explain the higher mobility of semiconductor inventors in Silicon Valley. Exploiting data on the origins of semiconductor producers with larger sales, we argue that the greater mobility of semiconductor inventors in Silicon Valley was due primarily to spinoffs and not the clustering of the semiconductor industry there or California?s ban on the enforcement of employee non-compete covenants. To the extent that greater inventor mobility benefited Silicon Valley semiconductor producers, the benefits were mainly experienced by entrants and not incumbent producers. Jelcodes:R23,L63 1 Spinoffs and the Mobility of US Merchant Semiconductor Inventors