Mark is a member of the litigation and enforcement practice group, where his practice focuses on complex civil litigation and enforcement matters. Mark has represented clients in the healthcare, private equity, energy, consumer products, defense, and financial services industries, among others, in a wide range of litigation matters including securities class actions, shareholder derivative suits, commercial disputes, qui tam litigation, employment disputes, and products liability claims. He has experience across all stages of civil litigation and alternative dispute resolution proceedings.
During his time at the firm, Mark served for six months as a Special Assistant District Attorney in the Middlesex County, Massachusetts District Attorney’s Office. While there, he prosecuted misdemeanor and felony offenses, including serving as lead counsel in jury trials, bench trials, and evidentiary motions.
Mark maintains an active pro bono practice, representing clients in areas including criminal defense, immigration, and public benefits appeals. Mark serves as co-team lead for income supports matters under the firm’s medical-legal partnership pro bono initiative.
Experience
- Regularly defend underwriters, issuers, officers, and directors in securities class action matters through dispositive motion practice, class certification, discovery, and appeal.
- Obtained summary judgment on behalf of major healthcare provider in False Claims Act case alleging billions of dollars in potential liability in connection with alleged regulatory compliance deficiencies.
- Representing technology company in federal multidistrict litigation relating to a data breach.
- Obtained complete dismissal and affirmance on appeal of securities and related derivative claims against solar energy company and its officers and directors, challenging public statements about the company’s exposure to COVID-related supply chain disruptions and commodity price spikes.
- Representing major financial institution in putative class action alleging fraud, antitrust, and civil RICO claims relating to operation of electronic foreign exchange trading platform.
- Obtained complete dismissal and affirmance on appeal of securities claims against underwriters in connection with technology company’s $1.9 billion IPO.
- Represented pharmaceutical company in False Claims Act litigation involving allegations off-label promotion and speaker program kickbacks, obtaining summary judgment and complete affirmance on appeal.
- Defended major life sciences company against multiple class action and individual lawsuits alleging products liability claims and violations of state consumer protection statutes, securing dismissal of class action claims in federal district court.
- Defended large, publicly held consumer goods company in securities class action challenging statements regarding manufacturing capacity and demand projections.
- Represented private equity client in confidential arbitration against departing managing director alleging breach of contract and fraud claims.
- Frequently represent and advise financial institutions, private equity firms, and portfolio companies in complex commercial disputes, shareholder derivative actions, third-party discovery matters, and pre-acquisition diligence.
- Commonwealth v. Celester - Counsel for Massachusetts Association of Criminal Defense Lawyers in amicus brief addressing the right to effective assistance of counsel in pre-arraignment custodial interrogation.