This paper is a study of licensing in a patent thicket. In a patent thicket licensing allows firms to avoid hold-up. It will have different effects on firms' R&D incentives depending on whether firms license existing or future patents. Building on a model of a patent portfolio race, firms'...

Licensing in a patent thicket allows firms to either avoid or resolve hold-up. Firms’ R&D incentives depend on whether they license ex ante or ex post. We develop a model of a patent portfolio race, which allows for endogenous R&D efforts, to study firms’ choice between ex ante and ex post...