Image: Kenneth M. Breen

Kenneth M. Breen

Partner, Litigation Department

New York

Phone: 1(212) 318-6344
Fax: 1(212) 230-7828


Ken Breen is a partner in the Litigation Department of Paul Hastings and, having completed a 10-year term as Global Chair of the Investigations and White Collar Defense practice, is now Head of the New York White Collar Defense practice.

Mr. Breen is a nationally renowned trial lawyer who is regularly recognized as one of the leading white collar criminal defense attorneys in the country. He defends corporations and executives in high-stakes investigations and trials involving a myriad of issues including securities fraud, health care fraud, consumer protection issues, money laundering, and anti-corruption allegations, often under intense media scrutiny. Many of these matters involve law enforcement and regulatory agencies from multiple jurisdictions and cross-border legal issues. He has tried 48 cases to verdict and argued 12 appeals as a federal prosecutor and defense attorney.

In ranking Mr. Breen among the leaders in White Collar & Government Investigations, Chambers USA notes that his clients hold him in "high esteem" and praise his "very shrewd mind," "exceptional legal vision," and "ability to look across the full spectrum of white-collar issues." According to Chambers, he impresses clients as "a very strong advocate," "an extremely clear thinker," “great communicator,” "very focused, incredibly direct and also really strategic," "dedicated, tireless and [someone who] can quickly and effectively understand legal issues and the business needs of his clients," and "phenomenal - [….] very good at his craft and […] a great strategist." Clients also describe him as an "extraordinarily effective trial counsel" who "comes with the experience, gravitas and intellect" that lets the other side know that he will be "really prepared to try the matter."

In January 2022, Mr. Breen obtained a precedent-setting appellate victory in the Second Circuit in U.S. v. Connolly, et al., where all counts of conviction against Matthew Connolly, the first U.S.-based trader to be charged with alleged manipulation of LIBOR, were overturned and judgments of acquittal directed. This win represents the only LIBOR-related criminal case in the U.S. or U.K. to be overturned on sufficiency of the evidence grounds and has received world-wide attention.

In January 2021, Mr. Breen secured a landmark appellate ruling in the Third Circuit in U.S. v. Gibson, et al., where all counts of conviction against David Gibson, the former Chief Financial Officer of Wilmington Trust Corporation, were overturned in a matter of first impression, and the two remanded counts were subsequently dismissed. The American Lawyer deemed it "a stunning reversal of criminal convictions for four executives of Wilmington Trust Corp. in a case dating back to the Great Recession."

Mr. Breen’s work in U.S. v. Connolly, et al., was shortlisted by Global Investigations Review as the Most Important Case of the Year for its impact on future government investigations, and led to his recognition by Law360 as a "Legal Lion" following Connolly’s no prison time sentencing, though facing 15 years. The subsequent appellate reversal in U.S. v. Connolly, et al. led to Mr. Breen's recognition as The American Lawyer's "Litigator of the Week," which described the win as a "remarkable turnaround" and acknowledged it as the second white-collar appellate reversal obtained by Mr. Breen in as many years. Mr. Breen was previously nominated for "Litigator of the Week" by The American Lawyer for his more than 10 years of work in U.S. v. Gibson, et al.

Prior to private practice, Mr. Breen served as a federal prosecutor in the U.S. Attorney's Office for the Eastern District of New York, where he was Deputy Chief of the Business and Securities Fraud Section; prior to that, in the U.S. Department of Justice Tax Division.


  • The American Lawyer, Litigator of the Week for securing a "remarkable turnaround" and complete appellate victory in U.S. v. Connolly, et al. (Second Circuit) with a precedent-setting opinion (2022)
  • Chambers USA Litigation: White Collar Crime & Government Investigations (2010-2021)
  • The Legal 500, Dispute Resolution-Corporate Investigations and White-Collar Criminal Defense: Advice to Corporates
  • The Legal 500, Dispute Resolution-Corporate Investigations and White-Collar Criminal Defense: Advice to Individuals
  • The Legal 500, Dispute Resolution-Financial Services Litigation
  • National Law Journal, Selected to the "Trailblazers" list recognizing the nation's leading attorneys in criminal law (2020)
  • The American Lawyer, Litigator of the Week Nominee for work as trial and appellate counsel securing a landmark appellate victory in U.S. v. Gibson, et al. (Third Circuit) and following the dismissal of the remaining remanded counts (2021)
  • Law360, Recognized as a "Legal Lion" for securing a sentencing ruling without any period of incarceration in U.S. v. Connolly, et al. (S.D.N.Y.) (2019)
  • Global Investigations Review (GIR), Recognized as lead trial counsel in U.S. v. Connolly, et al. (S.D.N.Y.), shortlisted by GIR as "Most Important Case of the Year" for its impact on future government investigations (2019)


  • Mr. Breen received his B.A. in English from Boston College in 1989, and his J.D. from the Boston College School of Law in 1992, where he was Annotation Editor and Staff Writer for the Uniform Commercial Code Reporter Digest.
  • Mr. Breen is a member of the New York bar and is admitted to practice in the U.S. District Court for the Southern and Eastern Districts of New York and the U.S. Court of Appeals for the Second and Third Circuits.


  • Represented Matthew Connolly, former manager at Deutsche Bank, in U.S. v. Connolly, et al. as lead counsel at trial and appeal in a matter involving allegations of wire fraud in connection with LIBOR submissions brought by the Department of Justice in the Southern District of New York.  Following a split jury verdict, our client was not sentenced to any term of incarceration after a significant sentencing departure.  The Second Circuit ultimately overturned all counts of conviction and directed judgments of acquittal. Our victory was recognized by The American Lawyer as a "remarkable turnaround" and has received world-wide coverage for its significance. Our work in this case was previously nominated by Global Investigations Review (GIR) as Most Important Case of the Year in 2019 for its impact on future investigations and by Law360 for securing a sentencing ruling without any period of incarceration.
  • Represented David Gibson, former Chief Financial Officer of Wilmington Trust Corporation, in U.S. v. Gibson, et lead counsel at trial and appeal in a matter involving allegations of accounting and securities fraud brought by the U.S. Attorney's Office for the District of Delaware.  Our client's conviction was overturned on all counts in a matter of first impression for the Third Circuit and the remanded counts were dismissed by the District of Delaware. The related SEC litigation was settled favorably. Our victories in this case have been recognized by The American Lawyer.
  • Represents a former senior executive of a financial institution in an investigation by U.S. and global law enforcement authorities of potential criminal conduct involving the alleged theft of over $3.5 billion from the Malaysian government-owned 1MDB investment company.
  • Represents a hotel owner in an investigation by the Department of Justice Fraud Section involving alleged mortgage fraud in excess of $500 million.
  • Represents multiple FinTech apps in investigations by the CFPB, NY Department of Financial Services, and other state regulators on issues involving online lending, interest rates categorized as "tips," monthly memberships at lending companies, and other consumer fees.
  • Represented a Middle Eastern oil and gas company in large-scale and well-publicized FCPA investigations by the SEC and DOJ.
  • Represented a prominent proprietary trading firm and registered broker-dealer in the SEC v. Galleon Management, LP, et al. and SEC v. Cutillo, et al., insider trading cases in the SDNY.
  • Represented a major construction company in an EDNY U.S. Attorney's Office investigation of the company's billing practices, which was resolved by a deferred prosecution agreement.
  • Represented the Swiss banking operations of a major international bank as Independent Examiner in connection with a DOJ Tax Division Program offering Non-Prosecution Agreements for Swiss banks. 
  • Represented a multinational Latin American conglomerate with U.S. operations in connection with an internal audit committee investigation relating to accrual accounting issues and whistleblower allegations. The matter was resolved confidentially.
  • Represented an international financial services company in an investigation by the CFPB regarding its loan servicing platform and other technology services provided. The investigation was concluded without any charges being brought against our client.
  • Conducted internal investigations for a leading state university system regarding various issues and issued public reports.
  • Represented former New York City Police Commissioner Bernard Kerik in criminal cases in the Bronx and U.S. District Court for the SDNY.

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