William T. Sullivan

Norton Rose Fulbright US LLP

San Antonio
United States
T:+1 210 270 7139
San Antonio
United States
T:+1 210 270 7139
William T. Sullivan

William T. Sullivan

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Bill Sullivan joined the San Antonio office in 2005. As counsel, his current practice focuses primarily on representation of property owners in disputes involving ad valorem taxation at both the administrative and judicial levels. His practice also includes commercial, medical malpractice, nursing home, and health care litigation, including all aspects of pretrial and trial work. 

Bill's experience includes representation of property owners, physicians, hospitals, nursing homes and other health care organizations. In addition, he has handled a variety of other civil litigation matters in areas including collections, contracts, deceptive trade practices, and commercial disputes. AV rating from Martindale-Hubbell

Professional experience

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JD, St. Mary's University School of Law, 1987
BBA, St. Mary's University, 1981

Bill was admitted to practice law in Texas in 1987. He is also admitted to practice law in the following courts: U.S. District Court, Western District of Texas (1988); U.S. District Court, Southern District of Texas (1990); U.S. District Court, Northern District of Texas (1990); U.S. Court of Appeals, Fifth Circuit; and U.S. Supreme Court (1991).

  • Texas State Bar

Property Tax - Negotiation and Litigation

A significant amount of Bill's practice involves the negotiation and litigation of property tax values on behalf of property owners throughout the State of Texas including, among others, petrochemical facilities, telephone and electric utilities, cogeneration facilities, utility scale wind and solar facilities, manufacturing plants, airlines, railroads, pipelines, rail cars, office buildings and private estates.  Bill's property tax experience includes representation of:

  • Owner of coal plant in one of the largest property tax jury trials ever tried in Texas; resulted in market value reduction in excess of $500 million per year
  • Owner of a Gulf Coast cogeneration facility; jury trial resulted in a tax reduction for the client in excess of $18 million for a 3-year period
  • Major Gulf Coast refinery in multi-year litigation resulting in a reduction in market value in excess of $100 million
  • Major telephone company in administrative proceedings relating to the comptroller's annual Property Value Study
  • Alternative wind energy operator in forcing appraisal district to change its method for the valuation of wind turbine sites
  • Automobile manufacturer regarding its manufacturing plant
  • Health care facility with regarding tax exemption issues
  • Property developer in maintaining open-space/wildlife management appraisal on property
  • Owner of a large private estate to achieve a significant reduction in property taxes

Health Care - Medical Malpractice Defense

Bill has significant experience in defending medical malpractice claims against physicians, hospitals, nursing homes, and other health care organizations.  Bill's medical malpractice experience includes defense of:

  • Home health care agency in a suit seeking $10 million dollars in damages for claims of abuse, neglect, and breach of contract
  • Physicians in medical malpractice suits seeking damages in excess of $1 million dollars
  • Nursing homes in suits alleging abuse and neglect

General Civil Litigation

Throughout his career, Bill has represented both individuals and corporations as Plaintiffs and Defendants in a wide variety of civil matters. The cases has handled on behalf of these clients include:

  • Representation of major gas storage company asserting claims against a supplier for DTPA and breach of contract.
  • Representation of financial institutions with regard to collection matters
  • Representation of air freight company regarding claims of misappropriation of trade secrets, breach of fiduciary duty and civil conspiracy
  • Representation of individual in family law matter involving custody dispute 
  • Defense of insurance broker in suit by insured alleging breach of insurance contract
  • Defense of home builder in suit alleging breach of construction contract and DTPA
  • Defense of financial institutions in suits regarding fraud, breach of contract and DTPA claims
  • Texas Top Rated Lawyer, LexisNexis Martindale-Hubbell, 2012 - 2015
  • Co-author, "Litigation of a Tax Exemption Dispute as to One Tax Year Does Not Apply to Subsequent Tax Years," Fulbright Briefing - Tax, November 6, 2012
  • "Fee Disputes: Lawyers Can Resolve Them, and Lawyers Can Avoid Them," San Antonio Lawyer, Sept.-Oct. 1998
  • "Appropriate Standard of Review in TCEQ Litigation Over a Property Tax Challenge," Texas A & M Real Estate Center 24th Annual Legal Seminar on Ad Valorem Taxation, San Antonio, Texas, August 2010
  • "Texas Property Tax Law Changes 2013 - 83rd Texas Legislature," Institute for Professionals in Taxation - San Antonio Chapter, September 2013
  • "Texas Property Tax Incentives, Exemptions and Proper Values - Claiming and Securing Them," Panel Presentation - Tax Executives Institute - Houston Chapter 26th Annual Tax School, Houston, Texas, May 2014
  • "Clean Energy Trends - Litigation and Legislation" - International Association of Assessing Officers Annual Legal Seminar, Chicago, Illinois, December 2014
  • "Clean Energy Trends - Litigation and Legislation" - Texas Oil & Gas Association Property Tax Representatives Annual Conference, Austin, Texas, February 2015
  • "Update on Oil & Gas Tax Litigation" - State Bar of Texas Annual Meeting - Tax Section, San Antonio, Texas, June 2015
  • "How to Put on a Winning Case - Judge's Perspective of a Property Tax Case" - Texas A & M Real Estate Center 29th Annual Legal Seminar on Ad Valorem Taxation, San Antonio, Texas, September 2015
  • "Legislative and Litigation Update" - International Property Tax Institute Oil and Gas Workshop, Houston, Texas, February 2016
  • "You Think it is Worth How Much?-A Look at Property Tax Disputes in Texas and More!" - Texas Advanced Paralegal Seminar, San Antonio, Texas, September 2016
  • "Property Tax Update 2017," Institute for Professionals in Taxation - San Antonio Chapter, September 2017
  • "Current Developments" - ABA/IPT Advanced Property Tax Seminar, New Orleans, Louisiana, March 2018
  • "Multi-Jurisdictional Assessment Problems" - ABA/IPT Advanced Property Tax Seminar, New Orleans, Louisiana, March 2019
  • San Antonio Bar Association, Member
    • Fee Dispute Committee, Chairman (1997 - 1998)
  • Institute for Professionals in Taxation, Member
  • St. Mary's University School of Law Board of Advocates Advocacy Competitions; recipient of award for dedication to advocacy as a volunteer judge for moot court and mock trial competitions (2010 and 2013)
  • Representing underprivileged persons in pro bono family law and estate matters
  • MacArthur High School Athletic Booster Club, President (2007 - 2009)
  • City of San Antonio Parks and Recreation Advisory Board (1999 - 2001)
  • Oak Park-Northwood Neighborhood Association, President (1997 - 2000)