This article argues that patents, although often viewed primarily in terms of their economic or incentivising function, also have an important but often overlooked private governance function. Inherent in the grant of a patent is the right given to the patent holder to exclude others from using that invention, and to set the parameters around the terms of use for the duration of the patent (via licensing). This right can in turn impact the trajectory of the patented invention and also multiple downstream inventions, potentially dictating uses in that field for the duration of the patent. [---]