Brian N. Desmarais

Senior Associate

Brian Desmarais’s practice focuses on advising clients on a variety of antitrust and competition matters, including assessing reportability under the Hart-Scott-Rodino (“HSR”) Antitrust Improvements Act, obtaining pre-merger clearance, responding to government requests for additional information, litigating complex civil and criminal matters, and providing antitrust compliance counseling.

Prior to joining the firm, Mr. Desmarais was an assistant vice president, associate general counsel at L’Oreal USA, Inc. where he advised the company on a range of antitrust compliance matters. Mr. Desmarais also previously was an antitrust associate in another global law firm.


  • AbbVie in its $550 million acquisition of medical device company, Soliton Inc.
  • Obtaining federal and state clearance, without conditions, for New York regional hospital system’s acquisition of another hospital system.
  • Therapeutics company in its $4 billion sale to a global pharmaceutical company following an investigation by the Federal Trade Commission and the United Kingdom’s Competition Markets Authority.  The transaction was ultimately approved without conditions.
  • Representing all parties to the largest healthcare merger in New England in two decades. The parties secured regulatory clearance at both the state and federal level.
  • SaaS provider in its $300 million sale of its LRO software and related assets.  The Department of Justice’s Antitrust Division cleared the sale, without conditions, after issuance of a Second Request.


  • JD, New York University School of Law, 2016
  • BA, History, Boston University, 2011, Phi Beta Kappa
  • New York
  • US District Court, Southern District of New York
Government & Military Service
  • Paralegal Specialist, US Department of Justice, Antitrust Division

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