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A model of patent trolls


  • CHOI, Jay Pil
  • GERLACH, Heiko


This paper develops a model of patent trolls to understand various litigation strategies employed by nonpracticing entities (NPE). We show that when a NPE faces multiple potential infringers who use related technologies, it can gain a credible threat to litigate even when it has no such credibility vis-à-vis any single potential infringer in isolation. This is due to an information externality generated by an early litigation outcome for subsequent litigation. Successful litigation creates an option value against future potential infringers through Bayesian updating. This renders a credible litigation threat against the initial defendant and allows the NPE to extract more rents. We discuss policy implications including the adoption of the British system of “loser-pays” fee shifting and the use of injunctive relief.

Suggested Citation

  • CHOI, Jay Pil & GERLACH, Heiko, 2015. "A model of patent trolls," Discussion paper series HIAS-E-9, Hitotsubashi Institute for Advanced Study, Hitotsubashi University.
  • Handle: RePEc:hit:hiasdp:hias-e-9

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    References listed on IDEAS

    1. Silvana Krasteva & Huseyin Yildirim, 2012. "Payoff uncertainty, bargaining power, and the strategic sequencing of bilateral negotiations," RAND Journal of Economics, RAND Corporation, vol. 43(3), pages 514-536, September.
    2. Jay Pil Choi & Heiko Gerlach, 2017. "A Theory of Patent Portfolios," American Economic Journal: Microeconomics, American Economic Association, vol. 9(1), pages 315-351, February.
    3. Carl Shapiro, 2010. "Injunctions, Hold-Up, and Patent Royalties-super-1," American Law and Economics Review, Oxford University Press, vol. 12(2), pages 509-557.
    4. Choi, Jay Pil, 2009. "Alternative damage rules and probabilistic intellectual property rights: Unjust enrichment, lost profits, and reasonable royalty remedies," Information Economics and Policy, Elsevier, vol. 21(2), pages 145-157, June.
    5. Lauren Cohen & Umit Gurun & Scott Duke Kominers, 2014. "Patent Trolls: Evidence from Targeted Firms," NBER Working Papers 20322, National Bureau of Economic Research, Inc.
    6. Che, Yeon-Koo & Yi, Jong Goo, 1993. "The Role of Precedents in Repeated Litigation," Journal of Law, Economics, and Organization, Oxford University Press, vol. 9(2), pages 399-424, October.
    7. James Bessen & Jennifer L. Ford & Michael J. Meurer, 2011. "The Private and Social Costs of Patent Trolls," Working Papers 1103, Research on Innovation.
    8. Lemley, Mark A & Shapiro, Carl, 2007. "Patent Hold-Up and Royalty Stacking," Competition Policy Center, Working Paper Series qt8638s257, Competition Policy Center, Institute for Business and Economic Research, UC Berkeley.
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    Cited by:

    1. Gerard Llobet & Jorge Padilla, 2016. "The Inverse Cournot Effect in Royalty Negotiations with Complementary Patents," Working Papers wp2016_1608, CEMFI.
    2. repec:eee:indorg:v:56:y:2018:i:c:p:168-203 is not listed on IDEAS

    More about this item


    patent portfolios; patent litigation; non-practicing entities; patent troll;

    JEL classification:

    • D43 - Microeconomics - - Market Structure, Pricing, and Design - - - Oligopoly and Other Forms of Market Imperfection
    • L13 - Industrial Organization - - Market Structure, Firm Strategy, and Market Performance - - - Oligopoly and Other Imperfect Markets
    • O3 - Economic Development, Innovation, Technological Change, and Growth - - Innovation; Research and Development; Technological Change; Intellectual Property Rights

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