Secrecy versus patenting

We develop an equilibrium search model of innovation with the possibility of multiple independent discovery. We distinguish innovations from ideas, and we view patents as probabilistic property rights that are constrained by the innovators' option to keep the innovation secret. We find that the patent system can simultaneously stimulate innovation, information disclosure and welfare. An optimal patent may provide more or less protection than secrecy, and in many cases, it provides less, suggesting that its main function is information spreading rather than rewarding the costs of the innovative activity.