Partner & Co-founder

Justin M. Sher

+1 212 202 2651

Justin counsels clients in complex business disputes. A thoughtful and tenacious advocate, he has served as lead counsel in multiple trials and regularly represents clients in federal and state courts, and in domestic and international arbitrations. 

Justin has achieved victories on behalf of both plaintiffs and defendants in a wide range of high-stakes matters, including cases involving contract disputes, allegations of fraud and securities fraud, business breakups, professional liability, breach of fiduciary duty claims, trust and estate issues, covenants not to compete, and disputes over intellectual property and trade secrets.  

Justin also advises clients in regulatory and criminal investigations. He has 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, Justin practiced 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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Obtained a $40 million judgment for a family office: Prevailed on behalf of a family investment office in a dispute with a public company over warrants issued in connection with a de-SPAC transaction. The family office sued when the public company refused the family office’s attempt to profitably exercise the warrants. After taking the matter over from a large law firm, Sher Tremonte persuaded a federal court that the terms of the warrant agreement had been met and obtained a judgment of approximately $40 million. 

Prevailed in a high-stakes global real estate battle: Obtained a $50 million judgment for a Singapore-based investment advisory firm focused on sustainable development in the hospitality industry. 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. 

Successfully obtained and defended a $13.5 million whistleblower award under the Dodd-Frank Act: After Sher Tremonte persuaded the SEC that its client was entitled to a $13.5 million whistleblower award arising from a financial institution’s violations of securities laws, a joint whistleblower challenged the award and sued Sher Tremonte’s client for fraud and breach of contract, seeking to obtain the award for himself. Sher Tremonte intervened on behalf of the SEC in the U.S. Court of Appeals for the D.C. Circuit to successfully defend the award and obtained full dismissal of the lawsuit in the U.S. District Court for the Central District of California.   

Obtained summary judgment in dispute over $81 million purchase of residential building: Prevailed on behalf of 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 developer and contractor were liable for breach of contract and negligent misrepresentation arising from defective construction. 

Prevailed in arbitration over termination of $175 million acquisition: Secured a complete victory, including an award of attorneys’ fees, in a dispute over a $175 million acquisition of twelve nursing facilities in Pennsylvania. The seller alleged that Sher Tremonte’s client had improperly backed out of the deal because of economic conditions caused by the global pandemic. The client denied this allegation and countered that the seller had breached its representations and warranties. Following a merits hearing, the arbitrator found that the seller had, in fact, breached its representations and warranties, entitling the client to terminate the deal. The arbitrator awarded the client the return of its multimillion-dollar deposit and directed the seller to pay attorneys’ fees and expenses.

Won summary judgment for a hedge fund/investment advisor and its principal: The plaintiff 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 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

Panelist, “Litigation Boutiques in London & New York – 15 Years On,” London International Disputes Week (June 2024)

“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)