William J. O’Sullivan

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William O'Sullivan

Phone: 860-258-1993
Fax: 860-258-1991
[email protected]
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William J. O’Sullivan litigates business disputes and commercial property disputes at both the trial and appellate levels. He frequently represents owners of closely held businesses in disputes with partners. Attorney O’Sullivan has tried cases in such areas as implied partnership, employment, trade secret, non-competes, fraud, alter ego, fraudulent transfer, civil theft, property condemnation, easement, and franchise law. He also handles creditors’ rights work, such as collections, foreclosures, replevins, bankruptcy nondischargeability proceedings, and suits on foreign judgments.

Bill has published more than two dozen law articles in legal and business journals, including the Connecticut Bar Journal’s “Business Litigation Year in Review” for each year since 2010. He has lectured on such diverse topics as recent developments in business litigation, civil procedure, legal ethics, the legal duties of departing employees, the calculation of damages in business cases, and the legal history of major league baseball.


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  • Business Litigation
  • Partnership and Shareholder Disputes
  • Creditors’ Rights
  • Professional Liability
  • Banking and Financial Institution Litigation
  • Real Estate Litigation
  • Alternative Dispute Resolution


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  • University of Connecticut School of Law, J.D., 1990
  • University of Connecticut, B.A., 1982


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  • Connecticut
  • United States Supreme Court
  • United States Court of Appeals, Second Circuit
  • United States District Court, District of Connecticut
  • United States District Court, Southern District of New York


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  • O’Sullivan McCormack Jensen & Bliss PC, f/k/a Baker O’Sullivan & Bliss PC, f/k/a Baker & Fulco PC
    • Shareholder (1997-Present)
    • Associate (1993-1997)
  • Cohn Birnbaum & Shea PC
    • Associate (1990-1993)


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  • Connecticut Bar Association
    • Chair, Litigation Section (2017-2019)
  • Hartford County Bar Association
  • Statewide Grievance Committee (2009-2018)


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  • Selected for inclusion in Best Lawyers in America, Commercial Litigation (2021-2023)
  • Recipient of the Martindale-Hubbell AV Peer Review Rating
  • Named a New England “Super Lawyer,” Business Litigation (2011-present)
    selection process described here


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  • Councilman, Rocky Hill, Connecticut, Town Council (2015-2019, 2021-present)
  • Past Member, Rocky Hill Planning and Zoning Commission
  • Past Member, Rocky Hill Economic Development Commission
  • Tenor, St. James Roman Catholic Church Choir


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Connecticut Bar Journal

Connecticut Lawyer

  • “Drafting an LLC Operating Agreement: A Litigator’s Perspective,” October/November 2012
  • “Pleading (and Waiving) the Fifth in a Business Tort Case,” March 2009
  • “Baseball Law 101,” April 2007
  • “Getting Leverage in a Business Tort Case: Hard Bargaining or Blackmail?”, August/September 2006
  • “Threatening Criminal Prosecution in a Business Tort Case,” November 2004
  • “Proving Fraud: The History and Future of Connecticut’s ‘Clear and Convincing Evidence’ Rule,” April 2004
    • Cited in C. Tait and E. Prescott, Connecticut Evidence (4th Ed. 2008), section 3.5.2, p. 118
  • “Consideration for Covenants Not to Compete: Is It Enough to Say, ‘You’re Not Fired?’”, February 1999
  • “Implied Strict Foreclosure Under Article 9 of the Connecticut UCC,” February 1998

Connecticut Law Tribune

  • “Decision Highlights Risk for Divorce Lawyers,” June 4, 2012
  • “High Court Nominee Pitched In To End Strike,” June 8, 2009
  • “Litigating Cases on a Budget: Risky and Getting Riskier,” June 30, 2005
  • “Litigating and Lobbying: To Win, You Might Need Both,” September 8, 2003

Hartford Business Journal

  • “In Recession, Watch for the Bleed,” May 18, 2009
  • “Starting a Partnership: Should You Share a Lawyer, Or Hire Your Own?”, January 19, 2004
  • “Pre-Printed Legal Forms Might Cost You a Little Now and a Lot Later,” October 16, 2003
  • “Attorney and Counselor – Make Sure Your Lawyer is Both,” April 14, 2003
  • “How to Discourage Your Employees From Stealing Your Company,” February 17, 2003
  • “Buying a Business – Is it a Legitimate Deal or a Scam?”, September 30, 2002
  • “Read Before You Sign,” March 25, 2002
  • “Warning to Ex-Employees: Copy, Delete, Get Sued,” August 7, 2000
  • “Beware: When Co-Signing or Guaranteeing a Loan, It’s Easy to Get In, but a Lot Harder to Get Out,” June 19, 2000
  • “No, You Can’t Get Legal Fees – and No, You Can’t Get Interest,” January 10, 2000
  • “Stop the Tape: Recording Phone Calls Can Backfire Disastrously,” November 15, 1999
  • “A Forgotten Asset in Selling a Business: The Valuable Star Employee,” October 4, 1999
  • “Avoiding Lawsuits by Your Ex-Employer,” September 20, 1999
  • “Under Connecticut Law, You May Own a Franchise – And Not Realize It,” July 19, 1999
  • “Beware of Treacherous Pitfalls When Selling Your Business – Remember, Cash is King,” April 5, 1999


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  • Obtained $2 million+ judgment for plaintiff in trial of alter ego claim arising from international insurance fraud
  • Obtained $500,000+ judgment for plaintiff in trial of embezzlement claim against company’s co-owner
  • Obtained judgment for defendant employer in trial of claim that employee was wrongfully terminated for exercising worker’s compensation rights
  • Obtained $250,000+ judgment for plaintiff in trial of condemnation appeal
  • Obtained $400,000+ arbitration award against municipality for breach of contract concerning revenues from redevelopment property
  • Obtained summary judgment for plaintiff in fraudulent transfer case
  • Obtained summary judgment for defendant in Bankruptcy Court adversary proceeding to void lien securing $750,000 claim; successfully defended on appeal
  • Obtained summary judgment for private commercial lender in fully contested mortgage foreclosure case
  • Obtained summary judgment for defendant in constructive trust action concerning bequeathed real estate; successfully defended on appeal


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Supreme Court
Stone v. East Coast Swappers, LLC, 337 Conn. 589 (2021) (Connecticut Unfair Trade Practices Act)
State v. Knybel, 281 Conn. 707 (2007) (criminal law; constitutional law)
Robinson v. Coughlin, 266 Conn. 1 (2003) (Uniform Fraudulent Transfer Act)
Bhinder v. Sun Co., Inc., 263 Conn. 358 (2003) (constitutional law; retroactive effect of legislation)
Bhinder v. Sun Co., Inc., 246 Conn. 223 (1998) (tort reform; apportionment of liability)

Appellate Court
Mierzejewski v. Brownell, 152 Conn.App. 69 (2014) (easement; res judicata)
Mitchell v. Redvers, 130 Conn.App. 100 (2011) (constructive trust; Connecticut Marketable Record Title Act)
Somers v. Chan, 110 Conn. App. 511 (2008) (suit by assignee of judgment; res judicata; supervisory power of court)
Davis v. Hebert, 105 Conn. App. 736 (2008) (restoration of withdrawn case to docket; mutual mistake)
LMK Enterprises, Inc. v. Sun Oil Co., 86 Conn.App. 302 (2004) (contract; eminent domain; franchise law)
Kazlon Communications, LLC v. American Golfer, Inc., 82 Conn.App. 593 (2004) (contract; release; offer-of-judgment statute)
Putnam Park Associates v. Fahnestock & Co., 73 Conn.App. 1 (2002) (commercial lease)



PPG Industries v. Webster Auto Parts, Inc., 128 F.3d 103 (2d Cir. 1997) (wrongful termination of distributorship; implied waiver of arbitration)
Ryan v. Sullivan, Hill, Lewin, Rez, Engel and Labazzo, 316 B.R. 101 (D.Conn. 2004) (fraudulent transfer; preference)
Pettola v. Nissan Motor Acceptance Corp., 44 F.Supp.2d 442 (D.Conn. 1999) (Consumer Leasing Act)