Mark B. Rosen

Mark B. Rosen is a partner at Pierce Atwood in Portsmouth, New Hampshire, where he handles high-stakes business litigation and complex legal counseling. His practice focuses on commercial litigation, class actions, securities litigation, shareholder disputes, and corporate governance. He represents companies and financial services firms in matters involving contracts, fiduciary duties, mergers and acquisitions, privatizations, financings, trade secrets, competition, employment issues, and other disputes arising from important business relationships and transactions.

Mark earned his J.D. from Benjamin N. Cardozo School of Law. His legal training supports a practice involving complex financial, corporate, securities, and governance issues. Before joining Pierce Atwood in 2010, he practiced in the Securities Litigation and Corporate Governance Group at Weil, Gotshal & Manges LLP in New York. That background contributes to his work with public and private companies, financial institutions, boards, executives, shareholders, and other clients facing sophisticated disputes or regulatory concerns.

Mark represents clients in shareholder and securities disputes, trade secret and non-compete litigation, banking and UCC matters, and government investigations. He counsels boards and companies on fiduciary duties, disclosure obligations, regulatory compliance, insider trading issues, and litigation-risk reduction. His experience includes SEC, FINRA, and state securities investigations, internal investigations for boards and audit committees, and class action defense. He has also represented owners and contractors in disputes involving complex commercial projects and government contract awards.

Mark B. Rosen combines litigation experience with preventive corporate counseling, helping clients respond to disputes while also reducing future exposure. His representative work includes defending merger-related shareholder claims, securities fraud class actions, consumer class actions, and regulatory investigations, as well as handling construction and banking disputes. He participates in professional and civic organizations and has provided pro bono counsel to underserved clients. His practice is built around careful analysis of complex business, financial, and governance problems.

Law Office Affiliations

• Partner, Pierce Atwood LLP
• Member, Massachusetts Bar Association
• Member, New Hampshire Bar Association
• Member, New York State Bar Association
• Member, Association of Defense Trial Attorneys
• Pro Bono Counsel, New Hampshire Legal Advice and Referral Center
• Vice President, Board of Directors, York Little League
• Treasurer, Board of Directors, Tenants Association at Pease, Inc. (2012-2018)
• Secretary, Board of Directors, Brixham Montessori Friends School (2014-2017)
• Member, New Hampshire Business and Industry Association 6 COVID-19 Business Reopening Liability Working Group

Licensed State

• Massachusetts
• New Hampshire
• New York

Education

• Benjamin N. Cardozo School of Law
  Juris Doctor (JD)
• Colgate University
  Bachelor of Arts (BA) in Classics

Awards & Badges