Diana Mahoney

Diana E. Mahoney

Senior Associate

Diana Mahoney's practice focuses on civil and regulatory litigation concerning securities and financial transactions. Ms. Mahoney has experience representing global financial institutions, funds, corporations, and individuals in connection with securities, shareholder, and commercial litigation and white collar investigations.

Ms. Mahoney also maintains an active pro bono practice. She represents indigent clients facing federal criminal charges and employees in connection with wage and hour claims in New York state and federal courts. Ms. Mahoney has also represented an individual criminal defendant in connection with his appeal to the New York Appellate Division, First Judicial Department.

While attending law school, Ms. Mahoney served on the Executive Board of the Moot Court Honor Society and as an Associate Managing Editor for the Brooklyn Journal of International Law. Ms. Mahoney served as a judicial intern for the Honorable E. Thomas Boyle, Magistrate Judge, in the United States District Court for the Eastern District of New York. She also worked as a student advocate in both the Civil and Criminal Divisions of the United States Attorney's Office for the Eastern District of New York. Ms. Mahoney received her BA in Political Science from the College of the Holy Cross.


  • Founder and partner in closed-end investment company in arbitration asserting claims of breach of contract and breach of fiduciary duties.
  • IT consulting company and its directors in securities and corporate governance litigation relating to a proxy battle, securing favorable settlements.
  • International educational organization and certain executives in securities class action and derivative matters arising from federal agency investigations and proceedings concerning advertising and marketing of student post-graduate performance, securing complete dismissal.
  • Major financial services firms in civil litigation concerning the structuring and trading of securitized products, including RMBS and CDOs.
  • Major national accounting firm in its defense of accountant and auditor malpractice actions brought in various state courts.
  • Major accounting firm in connection with an independence investigation by the SEC and PCAOB.
  • Leading investment bank in connection with RMBS and mortgage-related litigation in federal courts.
  • Multinational financial services firms in connection with inquiries from the SEC, CFTC, DOJ, FINRA, SROs and other regulators.
  • Pharmaceutical company in defense of hundreds of cases brought by governmental entities seeking to recover alleged public health and safety expenditures related to opioids.
  • Licensed financial services broker charged in the Southern District of New York for a scheme to fraudulently deposit a series of stolen stock certificates, also being investigated by FINRA.


Best Lawyers
"Ones to Watch"—Criminal Defense: White-Collar (2021–2023)


  • J.D., Brooklyn Law School, 2012, cum laude
  • B.A., College of the Holy Cross, 2008
  • New York
  • New Jersey
  • U.S. District Court, Southern District of New York
  • U.S. District Court, Eastern District of New York
  • U.S. Court of Appeals for the Second Circuit
  • Member, New York City Bar


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