William E. "Bill" Tanis


PHONE 303-628-3654
  • Biography
  • Insights
  • Memberships
  • Community Involvement
  • Firm News

Bill Tanis has been a partner of Ireland Stapleton Pryor & Pascoe, PC, one of the leading general practice law firms in Denver, Colorado, since 1982. Bill has extensive experience in general corporate and securities law matters, including initial public offerings, private placements, partnerships, joint ventures, acquisitions and dispositions, and entity formations. He has provided general advice to, and completed transactions for, public and private clients in industries as diverse as real estate, construction, equipment leasing, medical devices, banking, financial services, oil and gas, and renewable energy. Bill’s experience also includes counseling and representing companies undergoing ownership transitions. His client roster has also included several non-profit corporations. During his career, Bill has worked closely with boards of directors and management on strategic planning, financial matters, employee incentive plans, corporate governance issues, and restructurings.



  • Colorado


  • J.D., Harvard Law School, 1975
  • M.S. Economics, London School of Economics,  1972
  • B.A., Dartmouth College, 1971

Honors & Awards

  • Selected to The Best Lawyers in America® for Business Organizations (including LLCs and Partnerships) and Corporate Law, 2013-2024
  • Recognized by The Best Lawyers in America®  as a 2021 “Lawyer of the Year” for Business Organizations (including LLCs and Partnerships)
  • Colorado Bar Association
  • Colorado Bar Association Ethics Committee
  • Denver Bar Association
  • American Law Institute
  • Monte Pascoe Civic Leadership Award Committee Member
  • Board Member, Willows Water District