Changes

Quantifying the number of demand letters may feel like a Sisyphean task. The nature of demand letters creates a private relationship between a Patent Assertion Entity (PAE) or a law firm representing them and the company that allegedly infringed on a patent. These letters are mailed directly to the alleged infringer, and do not fall under a required part of discovery in the event of a lawsuit. Letters may warn or threaten a lawsuit from the PAE, but are not legally binding documents. Although the official number of demand letters related to patent infringements does not exist, several online resources host example of demand letters.

Bessen & Meurer (2012) estimate that patent asserting entitites non-practicing entities have accrued $29 million of direct costs to businesses during 2011.[http://www.pcworld.com/article/258395/patent_trolls_cost_tech_companies_29_billion_last_year_study_says.html][http://papers.ssrn.com/sol3/papers.cfm?abstract_id=2091210##] "The authors used a database of 1,630 patent troll lawsuits compiled by Patent Freedom. Because many of the lawsuits had multiple defendants, there was a total of 4,114 plaintiff-defendant pairs. The median defendant over all of these pairs lost $20.4 million in market capitalization, while the mean loss was $122 million."[http://arstechnica.com/tech-policy/2011/09/study-patent-trolls-have-cost-innovators-half-a-trillion-bucks/]