Partner & Co-founder

Justin M. Sher

+1 212 202 2651

Justin counsels and represents clients in complex commercial disputes as well as regulatory and criminal investigations. A thoughtful and tenacious advocate, he has served as lead counsel in multiple trials and regularly represents clients in federal and state courts, in arbitration proceedings, and before government agencies and regulatory bodies.

Justin has achieved victories on behalf of both plaintiffs and defendants in a wide range of high-stakes matters, including cases involving contract disputes, business breakups, professional liability allegations, breach of fiduciary duty claims, trust and estate issues, and allegations of securities fraud. He has also successfully defended clients against allegations of insider trading, market manipulation, government corruption, accounting fraud, antitrust violations, and tax fraud.

Justin thrives on complex issues, taking a strategic approach to finding solutions where others have failed. Clients laud his creativity, credibility among judges and opposing counsel, and unflagging commitment to achieving superior outcomes on their behalf.

Before founding Sher Tremonte in 2011, Justin worked at Davis Polk & Wardwell LLP and Kobre & Kim LLP, served as a Special Assistant District Attorney for the Kings County District Attorney’s Office, and, prior to law school, worked for the Financial Frauds Bureau of the New York County District Attorney’s Office.

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Prevailed in a high-stakes, high-profile global real estate battle: Obtained a $50 million judgment for a Singapore-based investment advisory firm focused on sustainable development in the hospitality and real estate industries. The judgment followed five years of litigation in the Commercial Division of the New York Supreme Court over the client’s claims of breach of contract, tortious interference, fraud, and unjust enrichment arising from the $358 million acquisition of an international luxury hotel chain.

Defeated a motion to dismiss in a lawsuit against a seller of a residential building: Represented a publicly traded real estate company in connection with litigation over its $81 million purchase of a residential building in Brooklyn. Despite a contract stating that the client was buying the building “as is,” Sher Tremonte’s team convinced the court that the company had viable claims against the seller and builder for fraud, breach of contract, and negligence.

Defended a health care executive against multiple claims in Delaware court: Represented an executive charged with trade secret misappropriation, fraud, and breach of restrictive covenants in a high-stakes matter before the U.S. District Court for the District of Delaware.

Won summary judgment for a hedge fund/investment advisor and its principal: The plaintiff, represented by Quinn Emanuel Urquhart & Sullivan LLP, alleged that Sher Tremonte’s client had breached a partnership agreement and asserted claims of fraud, breach of contract, and breach of fiduciary duty. After Justin’s cross-examination of the plaintiff, the Commercial Division dismissed all of the plaintiff’s claims based on its core finding that no partnership agreement existed because the “parties were merely discussing an investment plan that was never launched.”

Prevailed in a jury trial on behalf of a corporate travel firm and its director: The plaintiff, a competing travel agency, sued for misappropriation of trade secrets, unfair competition, and tortious interference, alleging that our clients had wrongfully taken client lists and had tampered with its email system for the purpose of diverting business. The jury accepted Justin’s argument that the client lists in question were not trade secrets and delivered a complete victory to Justin’s clients.

Other notable work includes:

  • Obtained a complete victory in a federal jury trial on behalf of a private college and two of its administrators in action brought by a former employee in the U.S. District Court for the Southern District of New York.
  • Prevailed in a case of first impression involving internet commerce and personal privacy issues. After hearing Justin’s arguments, the U.S. Court of Appeals for the Second Circuit held that resellers of personal data contained in drivers’ records are required to conduct a reasonable inquiry concerning a recipient’s permissible purpose before disclosing such information. The case represented an important victory for individual privacy and had wide-ranging implications.
  • Successfully defended three high-frequency traders in a criminal investigation under the Economic Espionage Act by the Southern District of New York.
  • Represented several entities and their principal as targets of a large-scale, high-profile international criminal investigation and forfeiture proceedings arising from $4.5 billion in funds allegedly stolen from a Malaysian development agency.
  • Successfully represented investors from China in a dispute with a New York-based real estate developer.


Named as a Top-Rated Business Litigation, White Collar Crimes, and Securities Litigation Attorney, Thomson Reuters’ Super Lawyers (2014-2023)

Ranked in Litigation: Securities by U.S. News – Best Lawyers (2024)

Recognized in Lawdragon 500 Leading Litigators in America: Complex Commercial Litigation and Regulatory & Criminal Investigations (2024)


Sustaining Member, Federal Bar Council (2016-present)

Climate Victory Council, League of Conservation Voters (2016-present)

White Collar Criminal Litigation Committee, New York State Bar Association (2007-present)

New York Chapter, American Inns of Court (2007-present)

Board of Directors, Legal Services of Hudson Valley (2017-2021)

Board of Directors, South Bronx Head Start (2017-2018)

News and Publications

“Investment Advisers Beware the Broad Confidentiality Clause,” New York Law Journal (December 5, 2016)

“Criminal Liability Under the Economic Espionage Act,” Atticus, Volume 26, No. 2 (Summer 2014)

“Travel At Your Own Risk: The Government Does Not Need a Warrant When It Investigates American Citizens Abroad,” American Bar Association White Collar Committee Newsletter (March 2009)