This paper exploits enlargement of the European Union as a natural experiment to provide evidence for cluttering of the trade mark register in Europe. Enlargement increased regulatory uncertainty for pharmaceutical firms because the number of medical regulators that had to approve invented names...

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'...

Post-grant validity challenges at patent offices rely on the private initiative of third parties to correct mistakes made by patent offices. We hypothesize that incentives to bring post-grant validity challenges are reduced when many firms benefit from revocation of a patent and when firms are...