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Mary Eaton

Partner, Co-head of Securities & Shareholder Litigation

Commercial litigation | Financial services | Pro bono | Securities and shareholder litigation |

She’s always in it to win it and is constantly thinking of new approaches and ways to get things done…she's a real litigator who wants to be in court and doesn't leave a stone unturned.

Chambers USA

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About Mary Eaton

Mary Eaton has extensive experience in complex commercial litigation, with a focus on securities class actions, shareholder derivative claims and other complex business disputes. Mary regularly represents issuers, boards of directors, board committees and senior management across a broad spectrum of industries (including financial services, private equity, asset management and technology) in a wide variety of disputes in federal and state courts across the country. In addition to her substantial trial experience, Mary regularly counsels clients on litigation avoidance and corporate governance matters.

Among her many accolades, Mary is perennially ranked among leading litigators by Chambers USA, Benchmark Litigation, Lawdragon, Crain's New York Business, Legal 500 US and Best Lawyers in America. In 2019, the American Bar Association awarded Mary the Stonewall Award for her contributions to the advancement of LGBT individuals and issues.

Securities litigation and enforcement

Mary represents issuers, underwriters, officers and directors in private securities litigation and in enforcement and examination proceedings before the SEC and other regulators.

Shareholder derivative claims

Mary has extensive experience in shareholder derivative matters, representing boards of directors, demand committees, issuers and senior management in connection with shareholder demands and claims of all sorts.

M&A and complex commercial disputes

Mary’s ability to distill and simplify the critical issues has enabled her to successfully represent clients across a broad array of industries in litigations of all types, securing favorable verdicts and settlements for her clients. As a result, Mary is regularly called upon to represent clients in a wide range of complex disputes, including rep and warranty, earn-out and other M&A disputes, corporate control contests, confidentiality and disclosure litigation, and contract and business tort claims.

Appellate practice

Mary has been the author of a number of amicus submissions to the United States Supreme Court on matters related to the proper interpretation of the Securities Act of 1933, the Securities Exchange Act of 1934, the Investment Company Act of 1940, and other federal securities laws on behalf of SIFMA, the Chamber of Commerce and the Mutual Funds Directors Forum. She has also represented a number of organizations before the Supreme Court on various social issues of national importance, including most recently in June Medical Services LLC v. Russo.

Pro bono

Mary is a firm believer in giving back to the community through pro bono service and has dedicated thousands of hours to managing and supervising various pro bono matters, both large and small. In recognition for that work, Mary has received a number of awards, including the Thurgood Marshall Award (Federal Bar Council), Outstanding Pro Bono Volunteer (New York State Bar Association), Lawyer Who Leads By Example (New York Law Journal), and Attorneys And Advocates Award (Sylvia Rivera Law Project), and is an eight-time recipient of the Pro Bono Publico Award (Legal Aid Society).

Recent work

Mary's recent representations included defending:

  • 3M Company, several officers and directors in securities class action and related shareholder derivative suits based on alleged failure to disclose contingent environmental liabilities.
  • Citigroup and its directors in several shareholder derivative actions and related securities class actions alleging that the board knowingly allowed the company to maintain insufficient operational controls and to violate the terms of regulatory settlements.
  • AstraZeneca, its CEO, and several other executives in securities class action challenging statements regarding clinical trial of its COVID-19 vaccine.
  • Tyson Foods and its officers and directors in securities class action alleging failure to disclose purportedly insufficient COVID-19 safety protocols at Tyson facilities.
  • Several underwriters in connection with securities class action challenging healthcare delivery platform InnovAge’s initial public offering.
  • CarLotz, its CEO, and its CFO in securities class action and related shareholder derivative suits alleging that defendants failed to disclose material information concerning CarLotz's inventory processing and its agreements with sourcing partner.
  • Pinterest in securities class action alleging that it made false and misleading statements with regard to future growth.
  • Pinterest and its board of directors in a stockholder derivative suit alleging breaches of fiduciary duty arising out of the alleged failure by management and Board to prevent discrimination.
  • Energy Recovery in securities class action filed in connection with termination of licensing agreement.
  • CBS and several of its officers and directors in securities class action alleging failure to disclose facts leading to #MeToo scandal with Les Moonves.


Mary received her LL.B. from Queen’s University, following which she clerked for Justice Bertha Wilson of the Supreme Court of Canada. Mary received her J.S.D. in 2000 and LL.M. in 1993, both from Columbia Law School.

Court Admissions

  • United States Supreme Court
  • United States Court of Appeals, 2nd Circuit
  • United States Court of Appeals, 3rd Circuit
  • United States Court of Appeals, 4th Circuit
  • United States Court of Appeals, 5th Circuit
  • United States Court of Appeals, 6th Circuit
  • United States Court of Appeals, 9th Circuit
  • United States District Court, Southern District of New York
  • United States District Court, Eastern District of New York

Recent Speaking Engagements

May 19, 2021
The SPAC Boom: What You Need To Know About Emerging Transactional, Litigation And Insurance Risks And Developments
Freshfields and Aon co-hosted event

March 4, 2021
“Fireside Chat” with The Honorable J. Travis Laster, Vice Chancellor, Delaware Court of Chancery
The Seventh Annual Berkeley Spring Forum on M&A and Governance