Portrait of William C. O'Neill
Recognized by 2014 Chambers USA for his work in insurance/reinsurance
William C. O'Neill, Partner Washington, D.C.
Phone: +1 202.624.2950
1001 Pennsylvania Avenue NW
Washington, DC 20004-2595

William C. O'Neill is a partner and co-chair of the firm's Insurance/Reinsurance Group. His practice focuses primarily on arbitrations and litigations on behalf of insurers, reinsurers, and health care companies. He is recognized as a top insurance and reinsurance attorney in Chambers USA (2014 thru present), as well as Euromoney's Guide to the World's Leading Insurance & Reinsurance Attorneys (2008 thru present) and the International Who's Who of Insurance and Reinsurance Lawyers.

Bill has been involved in hundreds of disputes involving issues in life, health, and property/casualty insurance and reinsurance issues. He has represented clients in disputes involving yearly renewable term reinsurance premiums, environmental and asbestos reinsurance allocations, maximum any one life warranties, extra-contractual obligations, sexual abuse claims, fronting arrangements, sunset and commutation clauses, actuarial and agency issues, vanishing premium life insurance policies, cedent insolvencies, long-term care premiums, follow the fortunes and follow the settlements, late notice, retention warranties, underwriting and claims handling practices, 9/11 issues, fraud, offset, misrepresentations, recovery of declaratory judgment expenses, and allegations of misconduct by brokers, managing general underwriters, and third-party administrators. These disputes center on many types of underlying exposures and business, including, variable annuities, individual life, health care, workers' compensation, long-term care, disability income, accident and health, asbestos, environmental, and construction defect exposures.

In addition to his dispute work, Bill counsels clients regarding business, strategy, and regulatory matters. He works closely with the firm's Health Care and Litigation practices and has worked on insurance-related issues with our International Trade, Intellectual Property, Corporate, and Antitrust practices. 

A few examples of Bill's recent experience include:

  • Defending a national managed-care organization against claims that it overcharged its reinsured by over $5 million in premiums. Following an extensive hearing, the arbitration panel denied the cedent's $5 million claim and awarded our client over $18 million on affirmative non-solicitation claims.
  • Obtaining a multi-million arbitration award for a cedent after its reinsurer challenged the reasonableness of the cedent's allocation of an underlying asbestos settlement.
  • Representing a global reinsurer in a dispute involving the acquisition of a large block of North American life insurance business through a coinsurance agreement that contained unsatisfied conditions to closing. The dispute centered on the interpretation of those conditions to closing and the impact of temporary impossibility of performance on the parties' rights and obligations under the coinsurance agreement.
  • Representing a reinsurer in a dispute with its retrocessionaire involving the reinsurer's obligations and ability to increase premiums on a large book of yearly renewable term life reinsurance.
  • Representing cedents and reinsurers in insurance and reinsurance disputes involving educational institutions, including issues relating to reinsurance of self-insured school pools, sexual abuse allegations, policyholder cut through claims, and allegations of bad-faith claim handling.
  • Representing a cedent in a dispute with its reinsurer over the reinsurer's challenge to a good faith settlement relating to the cedent's billings for losses incurred for the hospitalization of insured critically ill infants.
  • Representing a reinsurer in arbitrations over whether it could raise premiums on a book of yearly renewable term life reinsurance.
  • Representing a cedent in a dispute over the proper application of a retention warranty clause is a treaty reinsuring a block of disability income business. 
  • Working with a property/casualty reinsurer to create a new template for its self-insured pools reinsurance treaty.   
  • Representing a large domestic insurer in coverage litigation arising out of underlying "Clean Room" litigation.
  • Representing a reinsurer in a dispute with its cedent over a facultatively reinsured life insurance policy containing material misrepresentations that the insurer's agent was aware of at the time of underwriting but that were never disclosed to the reinsurer. Our client achieved a complete victory and the cedent was ordered to repay one hundred percent of the amount in dispute, plus interest.

Bill is a graduate of Cornell Law School and Towson University where he was named outstanding graduate of the Economics Department for 1992. He is a frequent speaker on reinsurance issues and has served on the faculty at numerous training seminars for reinsurance arbitrators. He is a member of the AIDA Reinsurance and Insurance Arbitration Society (ARIAS-US) education committee, a former chair of the Excess, Surplus Lines and Reinsurance Committee of the Torts and Insurance Practice Section of the American Bar Association, and a member of the American Health Lawyers Association.

In The News
In August 2009, Bill was featured in InsuranceLaw360 with a Q&A on his practice, the complexity of his cases, and his most notable accomplishments as a lawyer.


Admitted to Practice:  District of Columbia, Maryland

Highlights, News & Knowledge

Speeches & Presentations

  • "Current Issues in Life Reinsurance," AIRROC’s New York Regional Education Day, New York, NY (April 21, 2016). Presenter: William C. O'Neill.
  • ARIAS-U.S. Intensive Arbitrator Training Workshop, Tarrytown, NY (2013). Faculty Member: William C. O'Neill.
  • "Avoiding the Coin Toss: Proven Methods of Streamlining the Arbitration Process and Its Alternatives," ACI’s Forum: Reinsurance Disputes in Litigation and Arbitration, New York, NY (April 30, 2012). Participant: William C. O'Neill.
  • "Discussion of Extrinsic Evidence in Arbitration Proceedings (The Role of Underwriting Intent in Arbitration Proceedings)," ARIAS 2011 Spring Conference (May 2011). Presenter: William C. O'Neill.
  • "Utmost Good Faith: The Guiding Principle of Reinsurance," HB Litigation Conferences: 17th Annual Insurance Insolvency and Reinsurance Roundtable (June 24, 2010). Presenter: Bill O’Neill.
  • "Organizing The Arbitration," ARIAS-U.S. Arbitrator Continuing Education Series, New York, NY (2009). Faculty: William C. O’Neill.
  • "Investors Panel: Lessons from the Fall," Intermediaries & Reinsurance Underwriters Association Fall Conference, Galloway, NJ (2009). Panelist: William C. O'Neill.
  • "Risk-Sharing, Hedging, and Regulatory Considerations for a New Generation of Variable Annuities," ACI’s 3rd Annual Legal and Strategic Forum on Life Reinsurance, New York, NY (January 26, 2009). Participant: William C. O'Neill.
  • "Credit Default Swaps: Where Are We Going?" Crowell & Moring's Credit Default Swaps: Exploring The Controversy--Market Forces, Litigation, Regulation, Accounting and Tax Conference, New York, NY (2008). Speaker: William C. O'Neill.
  • Mealey's Reinsurance Litigation and Arbitration Conference, Washington, DC (2008). Co-Chair: William C. O’Neill.
  • Mealey's Fundamentals of Reinsurance Litigation and Arbitration Conference, New Orleans, LA (2007). Speaker: William C. O’Neill.
  • RAA's Re cCaims: Reinsurance Claims Management for Claims Professionals By Claims Professionals, Philadelphia, PA (2007). Moderator: William C. O’Neill.
  • Mealey's Fundamentals of Reinsurance Litigation and Arbitration Conference, Boston, MA (2006). Speaker: William C. O’Neill.
  • ARIAS Reinsurance Arbitration Workshop - Tarrytown, NY (2004). Faculty Member: William C. O'Neill.
  • ARIAS Reinsurance Arbitration Workshop - Washington, DC (2003). Faculty Member: William C. O’Neill.


  • Summary of United States Insurance and Reinsurance Law (2016). Co-Authors: Michael T. Carolan, Paul W. Kalish, William C. O'Neill, and Rachel P. Raphael.
  • Summary of United States Insurance and Reinsurance Law (April 2014). Co-Authors: Michael T. Carolan, Paul W. Kalish, William C. O'Neill, and Rachel Raphael.
  • Summary of United States Insurance and Reinsurance Law (April 2013). Co-Authors: Michael T. Carolan, Paul W. Kalish, and William C. O'Neill.
  • Reference Handbook on Insurance Company Runoff and Receiverships Property/Casualty & Life/Health (5th ed. June 2009). Contributing Editors (DC Circuit): William C. O'Neill and Matthew W. Cheney.
  • Coping with the CDS Crisis: Lessons Learned from the LMX Spiral (Spring 2009). Co-Authors: William O'Neill, Nilam Sharma, Michael Carolan and Zainab Charchafchi.
  • Recent Developments in Excess, Surplus Lines, and Reinsurance (Spring 2008). Co-Authors: William C. O’Neill, Michelle A. Jones and Lori T. Hildebrand.
  • The Duty of Utmost Good Faith in Facultative and Treaty Reinsurance (Winter 2007). Co-Authors: William C. O’Neill and Stacy A. Puente.
  • Key Principles and Concepts: Utmost Good Faith and Rescission (2007). Co-Authors: William C. O’Neill and Michelle A. Jones.
  • Consolidation of Reinsurance Arbitrations (2006). Co-Authors: William C. O’Neill and Ryan Craig.

Client Alerts & Newsletters

In the News

Firm News & Announcements

May.27.2016 Chambers USA Ranks 56 Crowell & Moring Attorneys and 19 Leading Practice Areas Among Best in U.S.
Oct.30.2015 21 Crowell & Moring Lawyers Recognized by the International Who's Who of Business Lawyers 2015
May.19.2015 Chambers USA Ranks 53 Crowell & Moring Attorneys and 20 Leading Practice Areas Among Best in U.S.
May.27.2014 Crowell & Moring's Insurance/Reinsurance Group Nominated for Chambers USA "Award of Excellence"
May.23.2014 Chambers USA Ranks 51 Crowell & Moring Attorneys and 19 Leading Practice Areas Among Best in U.S.
Dec.08.2008 Credit Market Leaders Discuss What’s Next in Market Forces, Litigation, Regulation, Accounting & Tax
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