following: Purchases a patent, often from a bankrupt firm, and then sues another company by claiming that one of its products infringes on the purchased patent; Enforces patents against purported infringers without itself intending to manufacture the patented product or supply the patented service; Enforces patents but has no manufacturing or research base; Focuses its efforts solely on enforcing patent rights; or Asserts patent infringement claims against non-copiers or against a large industry that is composed of non-copiers. The term "patent pirate" has been used to describe both patent trolling and acts of patent infringement. Related expressions are "non-practising entity" (NPE) (defined as "a patent owner who does not manufacture or use the patented invention, but rather than abandoning the right to exclude, an NPE seeks to enforce its right through the negotiation of licenses and litigation"), "patent assertion entity" (PAE), "non-manufacturing patentee", "patent shark", "patent marketer", "patent assertion company", and "patent dealer". Confusion over the usage of the term "patent troll" is clear in research and media reporting. In 2014, PricewaterhouseCoopers published research into patent litigation including a study of non-practicing entities including individual inventors and non-profit organisations such as universities. In quoting that research, media outlets such as the Washington Post labelled all non-practicing entities as patent trolls. Legal and regulatory history According to RPX Corporation, a firm that helps reduce company patent-litigation risk by offering licenses to patents it owns in exchange for an agreement not to sue, patent trolls in 2012 filed more than 2,900 infringement lawsuits nationwide (nearly six times higher than the number in 2006). In addressing the America Invents Act (AIA) passed by Congress in September 2011 reforming US patent law, U.S. President Barack Obama said in February 2013 that US "efforts at patent reform only went about halfway to where we need to go." The next indicated step was to pull together stakeholders and find consensus on "smarter patent laws." As part of the effort to combat patent trolls, the Patent Trial and Appeals Board was empowered to begin conducting the inter partes review (IPR) process in 2012. IPR allows an executive agency to review the validity of a patent, whereas previously such a review could only be conducted before a court. In 2018, the Supreme Court upheld the constitutionality of the IPR process in Oil States Energy Services, LLC v. Greene's Energy Group, LLC. In 2015, 45% of all patent cases