The patent world is quietly undergoing a change of seismic proportions. In a few short years, a handful of entities have amassed vast treasuries of patents on an unprecedented scale. To give some sense of the magnitude of this change, our research shows that in a little more than five years, the most massive of these has accumulated 30,000-60,000 patents worldwide, which would make it the 5th largest patent portfolio of any domestic US company and the 15th largest of any company in the world.

Tom Ewing & Robin Feldman, The Giants Among Us, STAN. TECH. L. REV. 1, (2012)