Aaron Katz


  • JD, magna cum laude, Harvard Law School, 2004; Harvard Law Review
  • BS (Political Science), summa cum laude, University of San Francisco, 2001


  • Massachusetts, 2005

Court Admissions

  • U.S. Court of Appeals for the Third Circuit, 2009
  • U.S. Court of Appeals for the Ninth Circuit, 2007
  • U.S. Court of Appeals for the Eleventh Circuit, 2018
  • U.S. District Court for the District of Massachusetts, 2009
  • U.S. District Court for the Eastern District of Michigan, 2016
  • Honorable Reena Raggi, U.S. Court of Appeals for the Second Circuit
  • The Best Lawyers in America (2021)
  • Burton Awards: Law360 Distinguished Legal Writing Award 2018
  • Benchmark LitigationTop Litigator Under 40” (2018)
  • Law360 Rising Star (2017)
  • Legal 500 (2017-2018)
  • Benchmark Litigation “Under 40 Hot List” (2016, 2017)
  • Law360 “Legal Lion” (May 2016)
  • National Law Journal “Boston Rising Stars” (2014)
  • Boston Business Journal, “40 Under 40” (2014) 
  • Foundation for Criminal Justice Award, recognizing amicus representation of the National Association of Criminal Defense Lawyers in United States v. O’Brien, 130 S. Ct. 2169 (2010) 
  • Massachusetts Super Lawyers “Rising Star” (2012-2019)

Aaron Katz


Aaron Katz is a partner in Ropes & Gray’s globally recognized Litigation and Enforcement practice group. Aaron represents corporate and individual clients in high-profile, complex criminal and civil matters at all stages of the proceedings.

Aaron’s client representations have spanned numerous industries, including pharmaceuticals, medical devices, health care delivery, energy, insurance, and finance.

As a trial lawyer, Aaron has represented corporate and individual clients at jury trials in the Southern District of New York, the District of Massachusetts, the Eastern District of Louisiana, and Massachusetts State Court. Aaron also has represented clients during criminal and civil pre-trial and post-trial proceedings in nearly a dozen different federal courts.

As an appellate litigator, Aaron has represented clients in five courts of appeals, the United States Supreme Court, and the Massachusetts Supreme Judicial Court.  Recently, Aaron authored an amicus brief on behalf of forty-four corporate and criminal law professors in a highly-publicized Supreme Court case involving the Affordable Care Act.

In addition to his trial and appellate work, Aaron has represented corporate and individual clients in connection with federal grand jury investigations, civil subpoena compliance, out-of-court negotiations with the Department of Justice, internal investigations and compliance program development, and international arbitration proceedings.

While at Ropes & Gray, Aaron has spent significant time on pro bono work, including representing torture victims before the United States Immigration Court, obtaining safe housing for indigent tenants, and collaborating with organizations that provide assistance to human trafficking victims. For the past eight years, Aaron has served as a capital habeas petitioner’s lead counsel.

Aaron has published several articles in both industry and academic journals, including articles addressing the FDA’s increased focus on corporate executives, constitutional limits on criminal penalties imposed on corporate defendants, and the False Claims Act. In 2012, Aaron co-taught a White Collar Crime seminar at Boston College Law School. In 2013, Aaron was a guest lecturer for a Death Penalty Litigation seminar at Boston College Law School.

As a student at Harvard Law School, Aaron served as an editor of the Harvard Law Review and as an oralist for the winning team in the 2002-03 Ames Moot Court Competition. After law school, Aaron completed a judicial clerkship at the United States Court of Appeals for the 2nd Circuit.


  • Trial counsel to a Boston-area real estate developer indicted on federal wire fraud and conspiracy charges in connection with a $75 million real estate transaction with Wynn Resorts Limited.  At the conclusion of a highly-publicized three week trial, the jury acquitted our client on all charges after less than six hours of deliberations.
  • Trial and appellate counsel to BP engineer charged by the Deepwater Horizon Task Force with two felony counts of federal obstruction of justice. Helped secure an acquittal on one count and an order granting new trial on the other, which the Fifth Circuit unanimously affirmed on appeal in a published decision. On remand, the Department of Justice agreed to dismiss the remaining felony count in exchange for a no-jail time, no-fine misdemeanor plea to a technical violation of 18 USC 1030(a)(5)(A).
  • In 2014, submitted an amicus brief to the Supreme Court on behalf of forty-four criminal and corporate law professors in Hobby Lobby et al v. Sebelius et al., a closely-watched case involving a challenge to the Affordable Care Act.
  • In 2012, successfully defended a major medical device manufacturer against a 13-count felony conspiracy and fraud indictment at a jury trial in the District of Massachusetts, with the government agreeing to voluntarily dismiss all thirteen felony counts, as well as all eighteen felony fraud counts that had been brought against the company's co-defendants, shortly after opening arguments.
  • Secured on behalf of a leading health care provider a dismissal with prejudice of a relator’s 80-page False Claims Act complaint alleging a multi-year kickback scheme and seeking substantial damages.
  • Helped negotiate favorable federal and state settlements on behalf of a leading health care provider alleged to have solicited product discounts in violation of the False Claims Act.
  • Successfully defended on appeal in the Third Circuit, on behalf of a nationally prominent pharmacy benefit manager, a district court’s dismissal with prejudice of a False Claims Act complaint premised on a then-novel implied false certification theory.
  • Appellate counsel to a natural gas derivatives trader who a federal jury had convicted of attempting to manipulate the price of natural gas.
  • Represented a multinational pharmaceutical company in connection with a proactive compliance review of a foreign subsidiary.
  • Represented a hedge fund in connection with an internal investigation into potential insider trading committed by an employee. 
  • Defeated a relator’s motion for an award of nearly $3 million in attorneys’ fees against a major health system in a precedent-setting decision out of the Southern District of New York. 
  • Represented a leading international insurance company at a civil jury trial in the Southern District of New York in a matter involving first-party environmental coverage claims made by a chemical manufacturer that polluted and was required to remediate significant portions of the Niagara River basin. 



  • Moderator, “The FCPA and Beyond: Navigating Global Compliance Risks and Government Investigations in the New International Economy”, Corporate Counsel Institute, Boston, MA, October 2014
  • Panelist, “Ethics and Tips for Attorney Voir Dire,” Boston Bar Association (September 9, 2014)
  • JD, magna cum laude, Harvard Law School, 2004; Harvard Law Review
  • BS (Political Science), summa cum laude, University of San Francisco, 2001
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