Mark D. Cahn



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.

Publications & News


December 2, 2016

Change and Continuity in Securities Regulation

Given the fluidity of the regulatory environment, making accurate predictions regarding what to expect from the SEC under a new Administration and a new Chair is difficult. Nevertheless, in this Client Alert we explore possible key areas of securities regulation that may be affected under the new Administration. This Client Alert was republished by the Harvard Law School Forum on Corporate Governance and Financial Regulation.

October 31, 2016

SEC Examiners Focus on Investment Adviser and Broker-Dealer Compliance With Whistleblower Rules

Last week, the SEC's Office of Compliance Inspections and Examinations (OCIE) issued a Risk Alert regarding examinations of investment adviser and broker-dealer registrants' compliance with key whistleblower provisions arising out of the Dodd-Frank Act.

October 11, 2016

New SEC Settlements Show Continued Focus on Whistleblower Protection and Severance Agreements

The Securities and Exchange Commission continues to pursue enforcement actions against companies for whistleblower-related violations. This WilmerHale Client Alert, which was also published by Bloomberg BNA's Securities Regulation & Law Report on December 5, 2016, examines the latest in a recent string of settled orders.

September 9, 2016

WilmerHale's FCPA Practice Lands GIR “Elite” Ranking

Global Investigations Review Just Anti-Corruption recently gave WilmerHale's Washington DC office an “elite” ranking for its Foreign Corrupt Practices Act (FCPA) practice, putting it among the top firms in the nation's capital.

December 22, 2015

Four Things Companies Should Know About the SEC’s 2015 Whistleblower Report

An article by Bill McLucas, Mark Cahn, Chris Davies and Arian June published in Bloomberg BNA's Securities Regulation & Law Report on December 21, 2015.

November 24, 2015

Four Things Companies Should Know About the SEC’s 2015 Whistleblower Report

The SEC recently published data showing significant increases in tips received under its Dodd-Frank Whistleblower Program. Released on November 16, the 2015 annual report also provided important guidance to companies on the SEC’s whistleblower-related priorities through fiscal year 2016.

September 15, 2015

Second Circuit Allows Whistleblower Retaliation Protection Without Reporting to SEC

In a 2-1 decision in Berman v. Neo@Ogilvy LLC, the US Court of Appeals for the Second Circuit ruled that whistleblowers who report securities law violations internally but not to the US Securities and Exchange Commission are protected under the Dodd-Frank Act from employer retaliation.

April 28, 2015

SEC Applies Whistleblower Interference Rule to Corporate Confidentiality Requirement

On April 1, the US Securities and Exchange Commission issued—in a settled administrative proceeding—a cease-and-desist order in In the Matter of KBR, Inc., directing that the respondent cease violating Commission Rule 21F-17(a).

December 23, 2014

Recent Insider Trading Decision

On December 10, the US Court of Appeals for the Second Circuit issued an opinion in United States v. Newman that could be the most consequential insider trading decision in a generation, but for reasons that virtually no one anticipated.

December 3, 2014

WilmerHale Partner Mark Cahn Discusses Securities Litigation Trends

WilmerHale Partner Mark Cahn appeared in a series of videos hosted by PwC outlining 2014 trends in securities litigation.

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.


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JD, Yale Law School, 1986, Editor, Yale Journal on Regulation

BA, summa cum laude, Tufts University, 1983, Phi Beta Kappa

Bar Admissions

District of Columbia

New York


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

Government Experience

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