Margaret H. Warner - McDermott Will & Emery

Overview


Margaret (Peg) Warner has served as first chair trial and appellate counsel in state and federal courts in over 30 jurisdictions. Her work has spanned antitrust, commercial, class action, environmental, healthcare, insurance, mass tort, product liability and reinsurance disputes. Peg has taken scores of cases to verdict/judgment before juries, judges and arbitration tribunals. Many of her cases have involved high-profile public policy issues from the Agent Orange litigation in the 1980s, environmental and Superfund litigation involving such notorious sites as Love Canal and the Hudson River in the 1990s, to sexual abuse, 9/11, antitrust, healthcare, ERISA and COVID-19 litigation in the 21st Century.

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Results


  • Lead arbitration counsel in hearing involving a $240 million loss portfolio transfer reinsurance agreement. After direct and cross examination testimony from eleven witnesses, obtained award terminating the agreement due to the cedent’s fraudulent misrepresentations
  • Lead trial counsel for defendant fiduciaries in an eight-day ERISA class action bench trial. Obtained judgment denying all injunctive relief and 97% of damages sought. Full affirmance in Tenth Circuit. Lead counsel for 401(k) fiduciaries in ERISA class action in Boston. Obtained summary judgment erasing $113 million damages claim
  • Lead trial counsel for defendant healthcare system defeating governmental effort to enjoin hospital closure; representation of healthcare systems in contractual and regulatory disputes nationwide

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Recognitions


  • Chambers USA, Insurance: Dispute Resolution: Insurer, 2021 and 2022, Insurance: Insurer, 2020-2023
  • Legal 500 US, Hall of Fame, 2021-2023
  • Best Lawyers in America, Commercial Litigation, 2008-2024 and Insurance Litigation, 2021-2025
  • Best Lawyers in America, Insurance Law, Washington, DC, 2008-2024

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Credentials


Education
University of Notre Dame, JD
St. Lawrence University, BA, cum laude

Admissions
District of Columbia

Courts/Agencies
US Supreme Court
US Court of Appeals for the Federal Circuit
US Court of Appeals for the District of Columbia Circuit
US Court of Appeals for the Second Circuit
US Court of Appeals for the Third Circuit
US Court of Appeals for the Fifth Circuit
US Court of Appeals for the Sixth Circuit
US Court of Appeals for the Seventh Circuit
US Court of Appeals for the Ninth Circuit
US Court of Appeals for the Tenth Circuit
District of Columbia Court of Appeals