Attorneys David M. Losier

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David is a member of the firm’s Business Litigation Department where his diverse practice includes complex business litigation and felony criminal matters. He represents individuals and companies in state and federal matters often involving breaches of fiduciary duty, misrepresentation and fraud. Additionally, Dave coordinates and oversees internal corporate investigations. He has successfully represented secondary, college and graduate school students in disciplinary actions brought before school judiciary panels and successfully resolved related criminal cases in a way that facilitates the students’ continued enrollment in the school.

Clients often rely on David for unexpected and emergent personal and business issues that require immediate advice. He recognizes the importance of being responsive, listening, assessing the problem and the client’s concern and assuring the client they are understood and they are not alone. David takes pride in taking on a client’s problem as if it were his own. His clients are often successful individuals at the helm of equally successful businesses. David takes an active and lead role in resolving the problem in a way that allows the client to remain focused on their business or personal endeavors.

“I am a trusted confidant who will tell it to them straight and help clients make informed, albeit sometimes difficult, personal or business decisions. I try to make each client feel as if they are my only client and their case is the most important case I am handling.”

David was a former Middlesex County assistant district attorney for nearly a decade before entering private practice. Prior to Sheehan Phinney, he was a partner at Burns & Levinson.

Key Cases

  • Counsel to prominent Boston-based graduate school leading an internal investigation into allegations of academic integrity violations and trademark infringement relating to national standardized test and test questions
  • Lead counsel for a national plastic manufacturer successfully defending against claims of unfair competition and fraud.
  • Lead counsel directing an internal investigation for a national tractor trailer school in response to allegations of embezzlement and fraud.
  • Lead counsel to criminal defendants and college students, obtaining dismissal of criminal charges and facilitating students continued attendance at prominent New England colleges and universities.
  • Lead counsel successfully representing an accountant and accounting firm being investigated by government authorities in connection with tax related fraud claims.
  • Lead counsel in a dispute among members/partners of a closely held company that invested in a multi-million-dollar townhouse development involving claims of breach of contract, breach of fiduciary duty and fraud.
  • Lead counsel representing a client pro bono in a multi-year Massachusetts Department of Children and Families (DCF) fair hearing process and companion juvenile court trial successfully disputing allegations of abuse and neglect. The DCF and juvenile court litigation resulted in the reversal of the DCF findings of abuse and neglect and the foster child being returned and then adopted by the client.


  • State of Massachusetts
  • U.S. District Court for the District of Massachusetts
  • U.S. Court of Appeals for the First Circuit
  • Admitted to several other state and federal jurisdictions, pro hac vice

Civic Involvement

  • Suffolk University Law School, Alumni Mentor
  • Colby College, Alumni Mentor
  • Middlesex Partnership for Youth, past Board Member
  • Acton Boxboro Youth Hockey Association, past Board Member and Coach
  • Past President of Coach Dante Muzzioli Scholarship Fund, award given to a Belmont High School boys hockey player for hard work and leadership


  • Martindale-Hubbell, Preeminent Rating
  • Rising Star by Massachusetts Super Lawyers®, Business Litigation & White Collar Crimes