Mark Cahn’s practice focuses on government and internal investigations, enforcement proceedings and litigation involving financial institutions, individuals and public companies. He first joined WilmerHale in 1988 and rejoined the firm after serving as General Counsel at the Securities and Exchange Commission (SEC) from 2011–2013.

Throughout his legal career, Mr. Cahn has represented public companies, financial institutions, individuals and corporations in internal corporate investigations, enforcement proceedings involving the SEC, FINRA and other regulatory bodies, and in federal and state court litigation. These matters have involved a broad range of issues, including financial reporting, regulatory compliance, accounting and disclosure inquiries, securities and other financial fraud, and insider trading.

In his position as General Counsel to SEC, Mr. Cahn provided legal advice to the Commission and its Divisions on all enforcement, litigation and regulatory matters. He provided legal and policy advice on administrative and operational issues, advised the Commission on the implementation of all rulemakings, and played a key role in the development of the SEC’s Whistleblower program. Mr. Cahn also served as Deputy General Counsel for Litigation and Adjudication at the SEC from 2009 to 2011, during which time he advised the Commission on enforcement recommendations and oversaw the litigation, appellate and adjudication functions of the General Counsel’s Office.

Professional Activities

Mr. Cahn serves on the Executive Council of the Securities Law Committee of the Federal Bar Association. He is also on the Board of Trustees of the SEC Historical Society.

Mr. Cahn has spoken to professional and industry groups on a wide variety of securities enforcement and litigation topics, including insider trading, supervision and internal corporate investigations.


Insights & News


  • Education

    • JD, Yale Law School, 1986

      Editor, Yale Journal on Regulation
    • BA, Tufts University, 1983

      summa cum laude Phi Beta Kappa
  • Admissions

    • District of Columbia

    • New York

  • Clerkships

    • The Hon. John J. Gibbons, US Court of Appeals for the Third Circuit, 1987 - 1987

    • The Hon. Herbert J. Stern, US District Court for the District of New Jersey, 1986 - 1986



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