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John O'Neill
Co-Chair, Business Disputes Group

John G. O'Neill


[email protected]
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John O'Neill
Co-Chair, Business Disputes Group
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John focuses his practice on business litigation and on insurance-coverage and professional-liability matters. He counsels and represents businesses and business owners in a range of high-stakes commercial disputes, including shareholder disputes and claims of breach of fiduciary duty, breach of contract, commercial fraud, and violation of consumer-protection statutes.

John has deep experience in complex insurance-coverage disputes. He regularly advises clients throughout the United States in coverage matters involving professional liability, director-and-officer liability, pollution liability, general liability, and property insurance. He also represents clients in coverage litigation and in suits for bad faith and extra-contractual liability. John previously served as the co-chair of the Boston Bar Association’s Insurance and Reinsurance Committee, and is presently a Director of the Massachusetts Insurance and Reinsurance Bar Association.

In the professional-liability area, John represents accountants, engineers, architects, attorneys, real estate brokers, and other professionals in the defense of malpractice claims and disciplinary proceedings. Complementing his experience in this field, John has served as a disciplinary-hearing officer for the Massachusetts Board of Bar Overseers.

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  • Secured summary judgment for contractor’s professional liability insurer in the Southern District of New York declaring that there was no coverage for a $110 million cost overrun lawsuit against insured developer
  • Secured summary judgment, subsequently affirmed by the Massachusetts Supreme Judicial Court, for architects and engineers insurer in multi-million dollar bad faith action involving novel issue of whether insured’s refusal to consent to settlement offers precluded liability for failure to effectuate a settlement when liability was reasonably clear.
  • Obtained favorable result for client in eight-day arbitration over coverage for costs incurred to remediate dioxins and VOCs resulting from plastics fire.
  • Represented architects and engineers insurer in bad faith action seeking over $20 million for excess verdict against insured engineering firm.
  • Secured summary judgment for contractor’s professional liability insurer declaring that there was no coverage for an ICC arbitration seeking $18 million against insured manufacturer.
  • Obtained summary judgment for legal malpractice insurer in West Virginia state court declaring that no coverage was available for a late-reported claim. The judgment was affirmed by the West Virginia Supreme Court of Appeals.
  • Won summary judgment in favor of a legal malpractice insurer declaring that there was no coverage for a fee dispute between an insured lawyer and his former law firm.
  • Secured partial summary judgment in favor of client declaring that insurer breached duty to defend against an NOR for historical releases of perchloroethylene on client’s property.


  • Obtained dismissal of consumer protection class action claims against a national salvage vehicle auction facility concerning disposing of unclaimed vehicles.
  • Secured summary judgment precluding recovery by class claimants in consumer protection action against release of information service provider for allegedly unlawful charges.
  • Obtained defense verdict for Oracle Applications implementer at a six-day jury trial on claims that the company improperly installed software.
  • Successfully defended an outsourced recruitment provider against claims for fraud and unfair business practices brought by a former customer, and secured a $2.1 million judgment on provider’s counterclaim for breach of contract.
  • Represented the selling shareholders of business in multi-million dollar fraud claim by corporate purchaser for alleged misrepresentations in transactional documents.
  • Obtained temporary restraining order preventing defaulting seller from conveying premises to anyone other than client after seller learned that corporate purchaser was interested in constructing development on property.
  • Successfully represented product manufacturer in multimillion dollar lawsuit against supplier of defective components to recover amounts paid to third parties for property damage caused by component failure.

Professional Liability

  • Secured summary judgment, subsequently affirmed by the Massachusetts Appeals Court, for trustees of a condominium on claims that they had wrongfully withheld insurance proceeds from a unit owner.
  • Obtained summary judgment in favor of a real estate attorney on purchaser’s claims that he had improperly certified title to the acquired property and failed to detect misdescription in the deed.
  • Secured dismissal of several lawsuits brought by an estate beneficiary against an attorney retained to represent the estate in litigation brought by her.
  • Represented numerous attorneys in disciplinary matters for alleged violations of the Rules of Professional Conduct.
Community Presence
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  • Boston Bar Association, Co-Chair Insurance and Reinsurance Committee, 2017-2020
  • Massachusetts Bar Association
  • Professional Liability Underwriting Society
  • Hearing Officer, Board of Bar Overseers, 2012-2014
  • Massachusetts Insurance and Reinsurance Bar Association, Board of Directors, 2018-present
Publications & Speaking Engagements
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  • Panelist, “Insurance Coverage for Professional Liability Attorneys,” Boston Bar Association, March 2022
  • Panelist, “The Past, Present, and Future of Business Insurance and Employee Benefits,” BankProvidence Webinar, September 2020
  • Author, “Insurance Coverage for Social Engineering Wire-Fraud Scams,” For the Defense, October 2018
  • Presenter, “Engineers Professional Liability Insurance,” Half Moon Seminars, October 2018, October 2017, and February 2015
  • Author, “Choice of Law in Bad Faith Claims,” For the Defense, May 2017
  • Author, “Can Damaging Internal Emails be Kept From the Jury,” New England In-House, August 2016
Professional Recognition
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  • Best Lawyers in America (Commercial Litigation, Insurance Law, Litigation–Insurance, and Professional Malpractice Law), 2023-Present
  • Massachusetts Super Lawyers (Business Litigation), 2009-Present