The authors develop a theoretical model where two competing firms need access to basic knowledge that only one firm owns. They determine the impact of an imperfect property right on the incentive to transfer that knowledge to the competitor. They compare these transfer strategies. (i) Patenting may lead to litigation costs that depend on the competition toughness. (ii) Keeping the knowledge secret involves no licence revenue but ensures a monopoly profit. (iii) The firm can also coooperate with the competitor and thereby avoids litigation. They show that whenever competition between both firms is low, making patentable basic knowledge promotes knowledge transfer through research cooperation.