William "Bill" Colgin

William "Bill" Colgin

Holland & Hart LLP

Recognized since 2023

Denver, Colorado

Practice Areas

Tax Law

Spinning circle Big letter B

Bill represents corporate taxpayers in complex, high-stakes federal tax controversies and tax litigation with significant implications for his clients’ bottom line.

Bill litigates in the US Tax Court, federal district courts, state courts, and appellate courts throughout the country. His cases and controversies typically involve high dollar amounts and tend to include international tax, transfer pricing, intellectual property, economic substance, and other high-profile areas of tax dispute.

Bill began his tax litigation career as a trial attorney in the Tax Division of the US Department of Justice and he draws on that experience to represent clients in complex Internal Revenue Service (IRS) examinations and appeals, anonymous IRS disclosure disputes negotiations, and coordinated resolution of multistate state tax issues. Bill continues to defend clients in federal criminal and civil tax investigations by the Tax Division of the US Department of Justice or the US Attorney’s Offices around the country.

Prior to joining Holland & Hart, Bill was a partner at Morgan Lewis.

Contact & Links


  • 555 Seventeenth Street, Suite 3200
    Denver, CO 80202-3979
  • 645 South Cache Street, Suite 100
    P.O. Box 68
    Jackson, WY 83001

Holland & Hart LLP
Headquarters: Denver, Colorado

185 The Best Lawyers in America® awards

61 Best Lawyers: Ones to Watch® in America awards

Best Law Firms Badge Full Firm Profile

Recognized in The Best Lawyers® in America 2023 for work in:

  • Tax Law


Your browser is not fully compatible with our automatic printer friendly formatting.

Please use the print button to print this profile page.

Spinning circle Big letter B