Professional Biography
Image of Robert L. Mahon

Robert (Bob) L. Mahon Partner

Firmwide Chair, Tax Practice

  • Seattle

    D +1.206.359.6360

    F +1.206.359.9000

    Seattle

    1201 Third Avenue, Suite 4900

    Seattle, WA 98101-3099

    +1.206.359.6360

    RMahon@perkinscoie.com

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Overview

Experience

News

Insights

  • 2021 | Book
    Cannabis Law: A Primer on Federal and State Law Regarding Marijuana, Hemp, and CBD
    Until now, there has been no single reference to guide cannabis lawyers through the full continuum of legal challenges in the industry. This treatise fills that gap from a sophisticated perspective by highlighting key issues in more than a dozen practice areas and covering the impact of cannabis law from U.S. state and federal, as well as Canadian, enforcement and regulatory agencies.
  • 07.09.2020
    Seattle Payroll Tax: Update and Frequently Asked Questions
    Updates
    The Seattle City Council passed a bill creating a new payroll tax on persons engaged in business in Seattle. While the ordinance has not yet been signed by the mayor (as of publication), the tax was passed by the council on July 6, 2020, by a veto-proof majority (7-2) and is expected to become law effective January 1, 2021.
  • 05.06.2019
    New Washington State Real Estate Excise Tax Legislation
    Updates
    The Washington Legislature completed its 2019 legislative session with the passage of sweeping changes to the real estate excise tax (REET).
  • 05.02.2019
    New Washington Business and Occupation Tax Legislation Affects Service Businesses
    Updates
    The Washington Legislature’s 2019 session produced four bills increasing business and occupation (B&O) taxes.
  • 06.22.2018
    South Dakota v. Wayfair: Practical Answers to Tax Questions Raised by Supreme Court Decision
    Updates
    Yesterday, the U.S. Supreme Court overruled more than 50 years of Commerce Clause precedent to hold that a state may require an out-of-state retailer with no physical presence in the taxing state to collect sales and use taxes on sales of goods and services delivered in the state.
  • 12.01.2017
    New Seattle Personal Income Tax Ruled Illegal
    Updates
    The King County Superior Court held on November 17, 2017, that Seattle’s recently adopted city income tax is illegal under Washington law.
  • 07.27.2017
    New Seattle Income Tax: Answers to Your FAQs
    Updates
    The City of Seattle adopted Ordinance 125339 on July 14, 2017, which imposes an income tax on Seattle residents and certain irrevocable trusts.
  • 05.01.2015
    Washington Court of Appeals: No Transactional Nexus Requirement or Dissociation for Washington B&O Tax
    Updates
    On April 292015, the Washington Court of Appeals issued an important tax decision in Avnet, Inc. v. Washington Department of RevenueDkt. No. 45108-5-II.  In its most significant holding, the court of appeals effectively eliminated the transactional nexus requirement for Washington B&O tax.  
  • 12.12.2013
    Oregon Supreme Court Decides Sales Factor Case
    Updates
    On December 12, 2013, the Oregon Supreme Court issued its decision in Tektronix, Inc. v. Oregon Dep’t. of Revenue.  The court held that the taxpayer’s receipts from the sale of goodwill, making up a part of the sale of a business division, were excluded from the sales factor under ORS 314.665(6)(a).
  • 07.11.2013
    Washington Service B&O Tax Rate Drops From 1.8% to 1.5%
    Updates
    In 2010, the Washington legislature passed significant B&O tax changes including the adoption of economic nexus and market sourcing for service activities, as well as the imposition of B&O tax on directors’ fees. However, the largest revenue raiser came from a temporary increase of the service B&O tax rate from 1.5% to 1.8% from May 1, 2010 through June 30, 2013. While there were concerns that the 2013 legislature would extend the “temporary” increase, it did not. As a result, the service B&O tax rate reverted to 1.5% beginning on July 1, 2013.
  • 04.01.2013
    2012 - 2013 Northwest State Tax Summary: Washington
    Articles

    Tax Analysts, State Tax Notes

    This article, Part II of a two-part series, highlights some of the major state and local tax questions and developments in Washington state.
  • 03.25.2013
    2012 - 2013 Northwest State Tax Summary: Oregon
    Articles

    Tax Analysts, State Tax Notes

    There was a great deal of state tax activity in Oregon and Washington in 2012 with the prospect of more developments to report in 2013. This article, Part I of a two-part series, highlights some of the activity in Oregon.
  • 12.20.2012
    No Oregon Income Tax Nexus for Company Owning Intangibles Used in State
    Updates
    A federal bankruptcy court judge has held that Washington Mutual, Inc. (WMI), a parent holding company that owned bank subsidiaries conducting business in Oregon, did not have nexus in Oregon by virtue of its ownership of the banks, the ownership of intangibles used by the banks in Oregon for no fee and the receipt of dividends from the banks.
  • 05.25.2012
    AOL Gets Its Day in Court (Finally) and Is Awarded Washington Sales Tax Refund
    Updates
    On May 9, 2012, the Washington State Board of Tax Appeals granted summary judgment to AOL, Inc., holding that AOL's purchases of services permitting its customers to connect with AOL's data center and the Internet were not subject to retail sales tax.  AOL Inc. v. Wash. Dep't of Revenue, No. 11-076 (Wash. B.T.A. May 9, 2012).  The procedural lessons of this case may be as important in Washington tax practice as the substantive case.
  • 04.12.2012
    2012 Washington Legislative Session: State Taxes
    Updates
    In double overtime, the Washington State Legislature ended the 2012 legislative session Wednesday morning, April 11, closing a roughly half-billion dollar shortfall for the two-year budget cycle.
  • 09.03.2010
    Washington State Retail Sales Tax Litigation
    Updates
    Collecting the right retail sales tax is sometimes a difficult task, but the government should not intentionally make it harder.  Unfortunately, because of a recent change in the law, retailers with operations in Washington state faced a confusing and uncertain tax environment, made worse by an unfortunate injunction obtained by the City of Bellingham and Whatcom County.
  • 05.04.2010
    Significant Tax Change in Washington State: Business & Occupation Tax Extended to Corporate Directors
    Updates
    On April 23, 2010, Governor Christine Gregoire signed into law Second Engrossed Substitute Senate Bill 6143, which extends Washington's business and occupation (B&O) tax to corporate directors beginning July 1, 2010.
  • 04.15.2010
    2010 Washington State Tax Legislation: What You Need to Know
    Updates
    On April 12, 2010 the Washington State Legislature resolved the budget impasse and adopted a $794 million tax package that the governor is expected to sign.  The tax bill, 2ESSB 6143, contains a number of major changes to Washington’s tax system.
  • Monthly, 2003 to present
    U.S. Supreme Court Update
    Articles
    Journal of Multistate Taxation and Incentives
  • 03.15.2023
    ABA/IPT Advanced Sales & Use Tax Seminar
    Speaking Engagements
    Moderator
    2023 ABA - IPT Advanced Tax Seminar / New Orleans, LA
  • 06.15.2022
    2022 Annual Labor & Employment Law Workshop (Virtual)
    Webinars
    A half-day, virtual employment law workshop, which covered a variety of topics, including an update on seminal federal and state employment law developments including in the areas of wage-and-hour law and the gig economy, family and medical leave and accommodations, arbitration and confidentiality in employment agreements, and other trends employers should watch in 2022.
  • 11.19.2020
    2020 Labor and Employment Law Virtual Workshop
    Webinars
    A half-day, virtual employment law workshop, which will cover a variety of topics, including diversity and inclusion in the workplace, navigating sensitivities around political law issues, key considerations for remote working, and recent employment law changes all business owners should know.

RELATED INFORMATION

Bar and Court Admissions

  • Washington

Education

  • University of Washington School of Law, LL.M., Taxation, 1996
  • The University of Iowa College of Law, J.D., with high distinction, 1995
  • Grinnell College, B.A., with honors, 1992