A patent troll, also called a patent assertion entity (PAE), is a person or company who enforces patent rights against accused infringers in an attempt to collect licensing fees, but does not manufacture products or supply services based upon the patents in question, thus engaging in economic rent-seeking. Related, less pejorative terms include patent holding company (PHC) and non-practicing entity (NPE). Generally not considered patent trolls are NPEs such as individual inventors, university research laboratories, development firms that offer their patented technologies to licensees in advance, and licensing agents that offer enforcement and negotiation services on behalf of patent owners.[1]