Private patent protection in the theory of Schumpeterian growth

We develop a Schumpeterian growth model with privately optimal intellectual property rights (IPRs) enforcement and investigate the implications for intellectual property and R&D policies. In our setting, successful innovators undertake costly rent protection activities (RPAs) to enforce their patents. RPAs deter innovators who seek to discover higher quality products and thereby replace the patent holder. RPAs also deter imitators who seek to capture a portion of the monopoly market by imitating the patent holder's product. We investigate the role of private IPR protection by considering the impact of subsidies to RPAs on economic growth and welfare. We find that a larger RPA subsidy raises the innovation rate if and only if the ease of imitation is above a certain level. With regards to welfare, we find that depending on the parameters it may be optimal to tax or subsidize RPAs. Thus a prohibitively high taxation of RPAs is not necessarily optimal. We also show that the presence of imitation strengthens the case for subsidizing R&D.