Margaret (Peg) M. Duncan focuses her practice on IP litigation, including patent, trademark and copyright litigation. Peg also focuses her practice on protection of intellectual property, including prosecution, counseling and transactions relating to global patent and trademark portfolios. Peg has represented numerous clients in federal courts and at the US Patent and Trademark Office in a wide variety of technologies and industries, including life sciences, chemical and computer hardware and software technologies, financial services, and food and beverage products.

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  • Won a jury verdict for defendant of non-infringement of a patent in the Western District of Wisconsin relating to computer networking devices
  • Won a jury verdict for plaintiff of infringement and validity of three patents and awarded an injunction in the Western District of Wisconsin relating to computer networking devices
  • Won summary judgment and attorneys’ fees for a defendant in the Northern District of Illinois regarding patents relating to fluorescent lighting

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  • Leading Lawyers Magazine – Business Edition, Top 10 IP Lawyers, 2018
  • The Best Lawyers in America 2011 to present, Litigation – Intellectual Property, Litigation – Patent, Trademark Law
  • Chambers USA 2005 to present
  • IAM Patent 1000 – The World’s Leading Patent Practitioners 2012 to present

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  • American Intellectual Property Law Association (AIPLA)
  • Federal Circuit Bar Association, Patent Litigation Committee
  • Intellectual Property Law Association of Chicago (IPLAC), Amicus Committee, vice chair

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Loyola University of Chicago School of Law, JD, 1981
Xavier University, BS, Natural Sciences (Biology and Chemistry), 1976
Indiana University, BS, Medical Technology, 1976


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