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Billy Marsh


Billy Marsh is an associate in the Litigation practice. He represents clients in high-stakes securities, shareholder, class action, product liability, and complex commercial litigation. He also conducts internal investigations and represents clients in government investigations and enforcement proceedings. Clients have praised Billy for his ability to quickly understand their business, grasp complex issues, and provide practical counsel and guidance.



Representative matters

Securities and Shareholder Litigation:

Defending an international chemical manufacturer against parallel putative class actions pending in federal and Texas state court alleging violations of the Securities Act of 1933 and Securities Exchange Act of 1934 in connection with two public stock offerings.

Obtained dismissal of securities class action filed against Tenet Healthcare challenging disclosures arising from regulatory proceeding.

Successfully defended BP Capital Management and related defendants in securities case alleging misrepresentations regarding hedge fund strategy. After filing a motion for summary judgment, obtained a voluntarily dismissal of plaintiffs' claims without the exchange of any consideration other than mutual releases.

Published Work

  • Author, "Protecting Board Communication Privilege," The Corporate Board (July/August 2021)
  • Author, "Compliance Post Affordable Care Act," New Perspectives of Healthcare Risk Management, Control and Government (February 2016)
  • Author, "Antitrust and Business Litigation," Texas Bar Journal (January 2016)

Speaking Engagements

  • Presenter, "Developing Effective Compliance and Audit Committees," Clear Law Institute (May 2016)



Attorney-at-Law, Texas


United States District Court for the Northern District of Texas

United States District Court for the Southern District of Texas

United States District Court for the Western District of Texas


Brigham Young University B.S., cum laude

University of Virginia School of Law J.D.


A&O Shearman was formed on May 1, 2024 by the combination of Shearman & Sterling LLP and Allen & Overy LLP and their respective affiliates (the legacy firms). Any matters referred to above may include matters undertaken by one or more of the legacy firms rather than A&O Shearman.