Image: Thomas A. Zaccaro

Thomas A. Zaccaro

Partner, Litigation Department


Thomas A. Zaccaro is a partner in the Investigations and White Collar Defense practice at Paul Hastings and based in the firm’s Los Angeles office. He focuses his practice on civil, commercial and criminal litigation in state and federal courts with a special emphasis on defending corporations and executives in government investigations and other criminal and regulatory proceedings. His representations also include general securities litigation, class actions, and shareholder derivative suits.

Earlier in his legal career, Mr. Zaccaro was the Chief Trial Counsel of the Securities and Exchange Commission’s Pacific Regional Office, where he was responsible for the management and supervision of all enforcement litigation conducted within the Pacific Region.

During his tenure with the SEC, Mr. Zaccaro often served as lead counsel in enforcement actions involving violations of the federal securities laws, including financial fraud, accounting fraud, insider trading, offering fraud, Ponzi schemes, and sales of unregistered securities. Mr. Zaccaro also served as an assistant U.S. Attorney for the Southern District of New York and as a Trial Attorney at the Department of Justice, Organized Crime and Racketeering Section.


  • Benchmark Litigation Guide, Litigation Star (2023)


  • Boston College Law School, J.D. (cum laude), 1984
    • Executive Editor, Boston College International and Comparative Law Review 
  •  Georgetown University, B.A. (magna cum laude), 1981


  • Successfully defended former CEO of sTec, Inc. in jury trial victory against the SEC in an insider trading case.
  • Led internal investigation for investment advisor concerning potential cross-trading violations.
  • Represented investment advisor accused by the SEC and CFTC of causing the May 2010 "flash crash." Investigation concluded without any enforcement proceedings.
  • Represented the independent directors of the American Funds in a shareholder derivative action. Obtained dismissal with prejudice upon a motion to dismiss.
  • Represents numerous directors, officers and employees of public corporations, investment advisers and broker-dealers in SEC and DOJ insider trading investigations.
  • Represents NYSE- and NASDAQ-listed companies in FCPA investigations conducted by the SEC and the Department of Justice.
  • Conducted numerous internal investigations on behalf of corporations and their Audit Committees concerning accounting, revenue recognition, disclosure and various other securities-related issues.
  • Represented several NYSE- and NASDAQ-listed companies, as well as individual officers and employees, in stock option investigations being conducted by the SEC and the Department of Justice and in related shareholder derivative litigation.
  • Represented NASDAQ-listed corporation in shareholder derivative action alleging fraudulent proxy disclosures concerning executive compensation. Case was dismissed at pleadings stage.
  • Conducted internal investigation on behalf the board of an investment advisor following whistleblower complaint of potential personal trading violations.
  • Conducted internal investigation on behalf of board of a NASDAQ-listed corporation concerning potential insider trading by an executive officer.
  • Represented CFO of NASDAQ-listed medical company in SEC and DOJ investigations concerning disclosure fraud. Investigations concluded without any criminal charges or SEC enforcement proceedings.
  • Represented management-level employees of a pharmaceutical company in DOJ False Claims Act investigation. Investigation was concluded without any criminal charges being filed.
  • Represented a member of the San Diego City Council in connection with several investigations concerning the City’s disclosures in certain bond offering documents. Investigation concluded without any SEC enforcement proceedings. 
  • Represented former CFO of NASDAQ-listed corporation in SEC and DOJ investigations concerning allegations of accounting fraud. Investigations concluded without any criminal charges or SEC enforcement proceedings.

Engagement & Publications

Practice Areas

Financial Restructuring
Securities Litigation
Anti-Corruption and FCPA
Securities Enforcement
Investigations and White Collar Defense
White Collar Defense




California Bar


Boston College Law School, J.D. 1984
Georgetown University, B.A. 1981

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