I enjoy working with clients and their other advisors to achieve clients’ objectives.

How I represent clients at Schwabe

I assist clients with tax and business law issues in ‎transactions and controversies. My transactional ‎practice emphasizes choice of entity and formation, ‎mergers and acquisitions, real property development, ‎foreign bank account and asset reporting, and tax-‎exempt entity formation, qualification, and operation. ‎On the controversy side, I handle a wide variety of tax ‎collection and controversy matters, both federally and ‎at the state level in Oregon and Washington. I litigate ‎cases before the United States Tax Court and the ‎Oregon Tax Court, where I formerly clerked for the ‎Hon. Henry C. Breithaupt.‎

Since the enactment of Oregon’s Corporate Activity Tax (“CAT”) in ‎‎2019, I have been at the forefront, frequently speaking on the CAT and co-authoring a number of articles on CAT developments. For more on the CAT, please refer to those articles here. To be ‎added to our email list of CAT updates, please contact me at ‎deller@schwabe.com.‎

I am also an Adjunct Professor at Lewis and Clark Law School and an ‎Adjunct Instructor in the School of Business Administration at ‎Portland State University.‎


“Almost 20 years ago, Mark Stayer was referred to us for real estate transactions. We have ‎used him ever since in multiple states. Recently we have also had the pleasure of working with Dan Eller on tax questions. In ‎every case, they have been very professional and a pleasure to work with.‎”



  • University of Washington, School of Law, LL.M., Taxation (2008)
  • University of California, Los Angeles, Bachelor of Arts degree in Business Economics (1992)
  • Lewis & Clark, Law School, Juris Doctor degree, cum laude (2004)
  • Portland State University, Master of Science degree in Financial Analysis (2001)


  • Oregon State Courts
  • Washington State Courts
  • U.S. Court of Appeals - Ninth Circuit
  • U.S. Court of Appeals - Federal Circuit
  • U.S. Court of Federal Claims
  • U.S. District Court - District of Oregon
  • U.S. District Court - Eastern District of Washington
  • U.S. District Court - Western District of ‎Washington
  • U.S. Tax Courts
  • U.S. Supreme Court


  • FEI Portland, Member (2023-present)
  • American College of Tax Counsel, Fellow
  • Oregon State Bar Taxation Section, Past Chair
  • American Bar Association, Taxation Section, Member


  • JD Supra Readers’ Choice Awards, Top Author: Tax (2021)
  • Oregon State Bar Taxation Section Pro Bono Award, Inaugural Recipient (2018)
  • Thomson Reuters, Oregon Rising Stars (2009 – 2010, 2012 – 2014)
  • Lewis & Clark Law School, Andrea Swanner Redding Outstanding Mentor Award
  • Oregon State Bar Taxation Section, New Tax Lawyer Committee, Mentor of the Year (2012)
  • Lewis & Clark Law School, Cornelius Honor Society
  • Lewis & Clark Law School, Joyce Ann Harpole Scholarship
  • Selected to the Oregon Super Lawyers List, Tax (2016 – 2023)

Additional Events

Oregon State Bar Taxation Section CLE Luncheon Series
TEFRA Repeal
May 25, 2017

Mid-Valley Tax Forum
TEFRA Repeal Presentation
January 17, 2017 (Salem, Oregon)

Oregon State Bar Real Estate & Land Use Section
Real Estate Choices-of-Entity and Hot Tax Topics for the RELU Professional
November 15, 2016

The Life Cycle of an Oregon Department of Revenue Case
Presented to Legal Aid Services of Oregon
September 23, 2016

Pub Talk: The Many Specialties in Tax and Whether to Specialize
Oregon State Bar Taxation Section
September 22, 2016

Community Activities

  • Portland Tax Forum, Board Member and Former Chair
  • Oregon State Bar, Taxation Section, Laws Committee, Former Chair
  • Lewis and Clark Law School, Joyce Ann Harpole Award Committee, Member
  • Lewis & Clark Law School Alumni Board, Former Member and Former President
  • Oregon, Southwest Washington, Idaho, and Montana Chapter of the Leukemia & Lymphoma Society, Former Board Member and Former Chair
  • Portland State University Graduate Alumni Ambassador Council, Former Council Member
  • Oregon State Bar, Taxation Section, Portland Luncheon CLE Series, Former Co-Host
  • Lake Oswego School District Foundation, Former Board Member
  • Lewis & Clark Law School, PILP Stipend Committee, Former Member

Outside Interests

Cycling, photography and spending time outdoors with friends and family.

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