The decision to regulate involves the identification of markets where simple assignment of property rights is not sufficient to ensure satisfactory competitive results, usually because some type of market failure obtains. By contrast, if property rights are well defined when they are initially created and can subsequently be traded to some reasonably competitive equilibrium, then regulation is thought not to be necessary. In such cases the antitrust laws have a significant role to play in ensuring that the market can be as competitive as free trading allows. One problem with the patent system is that once a patent is granted it has neither significant ongoing regulation nor a clear and effective initial assignment of property rights that serves to make the market perform competitively. One could attempt to correct this system either by defining the initial assignment of property rights more clearly or else by imposing more elaborate regulation that continued through the period subsequent to patent issuance and perhaps even for the remainder of a patent's enforcement life.
In the past half century we have come to think of patents less as a species of "monopoly" and more like a kind of "property." But this revised conception of patents as property rather than monopoly remains incomplete in significant ways.While "property" is rhetorically much less threatening than "monopoly," that is so because traditional property rights come with built in limitations that serve to discipline the power to exclude -- namely, boundaries and priority rules that define the extent of ownership and give notice to non-owners. Patent law has become "property" without either. Indeed, many of the opportunities for anticompetitive behavior in the area of patents can be traced back to the twin problems that boundaries are not clear and priority, and thus ownership, is so difficult to determine. This suggests an increased role for either post-issuance antitrust or regulation.
Hovenkamp, Herbert J., "Patents, Property, and Competition Policy" (2009). Faculty Scholarship. 1797.