Tax Controversy & Litigation

Close-up of steel ball in round maze.

Navigating a complex, evolving landscape

Against a backdrop of amplified public and governmental discourse on tax avoidance, and increasingly complex and ever-changing rules and compliance requirements, corporations face greater scrutiny of their tax planning practices and a growing risk of involvement in tax controversy. As the size and stakes of tax disputes increase, the reputational and financial consequences to businesses also increase, with potential exposure capturing the attention of executive leaders and enterprise risk managers. Access to strategic and experienced tax law counsel is imperative in mitigating the impact of tax disputes and litigation.

Recognized as the “[c]ornerstone of the Canadian tax market with a formidable presence in tax litigation,” (Chambers Global 2015), Osler advises Canadian and foreign-based corporations doing business in Canada on all aspects of avoiding, managing and litigating tax disputes. Our advice, which leverages our market-leading tax planning and transfer pricing expertise, is focused on prevention and risk management.  We work closely with our clients’ business and legal teams, providing focused and strategic advice to help our clients avoid debilitating tax payments and penalties – especially in “bet the company” controversies.

Our clients benefit from our considerable experience in proactively managing and resolving audit and appeal disputes with the CRA, as well as our in-depth knowledge of the Income Tax Act and the CRA’s decision-making processes. While we work with clients to avoid going to court whenever possible, Osler litigators have successfully represented clients in several of the most significant tax litigation cases in Canada. Osler has acted as counsel on landmark and complex tax cases of national importance affecting large classes of taxpayers, before the Supreme Court of Canada, the Federal Court of Appeal, the Tax Court of Canada and other courts in numerous tax cases that have shaped Canadian tax law. Our work includes acting as counsel on the first GAAR case in which a taxpayer succeeded before the Supreme Court of Canada and the first transfer pricing case in which a taxpayer succeeded before the Supreme Court of Canada.  Osler’s strategic focus and the depth and breadth of our experience is invaluable to our clients. Our clients also benefit from the experience and judgment of lawyers in our industry-leading civil litigation group and our sophisticated litigation support team.

Osler is at the leading edge of the market, advising clients on the full range of contentious tax issues including:

  • Transfer pricing
  • Tax avoidance and the general anti-avoidance rule in the federal and provincial context
  • Resources taxation
  • Computation of profit
  • Goods and services tax
  • Interest deductibility
  • Scientific Research and Experimental Development (SR&ED) credits
  • Treaty interpretation
  • Corporate reorganizations
  • Corporate control
  • Shareholder and employee benefits
  • Deductibility of settlement payments and other types of expenses
  • Foreign tax credits
  • Meaning of inventory
  • Residence for tax purposes
  • A range of administrative and procedural tax matters (including requirement letters, access to information and privilege related issues)


  • Canada Trustco Mortgage Co. v. The Queen, 2005 SCC 54; 2004 DTC 6119 (F.C.A.) – The Supreme Court of Canada held that GAAR did not apply to a sale-leaseback transaction.
  • The Queen v. GlaxoSmithKline Inc., 2012 SCC 52 - The Supreme Court of Canada articulated the proper approach to determining appropriate arm’s length prices in Canadian law.
  • The Queen v. General Electric Capital Canada Inc., 2010 FCA 344 – The first transfer pricing case in Canada to apply the modern transfer pricing regime set out in section 247 of the Income Tax Act (Canada), in addition to the regime set out in former subsection 69(2).
  • TD Securities (USA) LLC v. The Queen, 2010 TCC 186 - Overturned the CRA’s long-standing policy of denying treaty benefits to US limited liability companies.
  • Inter-Leasing Inc. v. Ontario (Minister of Revenue), 2014 ONCA 575, rev’g 2013 ONSC 2927 – Application of the Ontario provincial GAAR regime to interprovincial tax planning.
  • Husky Energy Inc. et al v. Alberta / The Queen, 2011 ABQB 268, aff’d 2012 ABCA 231 – Application of the Alberta provincial GAAR regime to interprovincial tax planning.
  • Daishowa – Marubeni International Ltd. v. Canada, 2013 SCC 29 – The tax treatment of the assumption of reclamation obligations.
  • CIBC World Markets Inc. v. Alberta / The Queen, 2011 FCA 270  - Successful GST appeal dealing with the fundamental principle of claiming input tax credits for purposes of the goods and services tax.
  • The Queen v. 3850625 Canada Inc. (Formerly Fording Coal, Ltd.), 2011 FCA 117 – Decision is favourable for many resource businesses seeking a broad interpretation of the resource allowance rules.
  • Gifford v. The Queen, 2004 SCC 15 – Confirmed the treatment of interest expense as a current expense to moneylenders.
  • Telus Communications Inc. v. Canada (Attorney General), 2015 ONSC 6245 - Rectification of error in an election for the alignment of a multi-tier partnership fiscal year end.





Al Meghji

Partner, Tax


Louis Tassé

Partner, Tax


Edward Rowe

Partner and Co-Chair, Tax


David Jacyk

Partner, Tax


  • Chambers Canada: Canada's Leading Lawyers for Business: Recognized in Tax (Band 1)
    • "The depth of the team is unbelievable."
    • "Top operator in the market."
    • "I enjoy working with them - they bring a level of technical expertise that is extremely deep. We get tremendous insight."
    • "Osler is technically strong. They are also commercial and will take a view supported by reasoned and principled judgement in areas with no clear answer. I am very happy with their advice."
  • Chambers Global: The World's Leading Lawyers for Business: Recognized in Tax (Band 1)
    • "They are a premier tax group."
    • "They bring credibility and objectivity in their advocacy."
  • The Canadian Legal Lexpert Directory: Recognized in Litigation - Corporate Tax (Calgary, Alberta; Toronto, Ontario; Montreal, Quebec)
  • The Lexpert/American Lawyer Guide to the Leading 500 Lawyers in Canada: Osler lawyers recognized as leaders in Tax Litigation
  • Benchmark Litigation Canada: Received the 2021 ‘Impact Case Award’ for our work on Cameco Corporation v. Her Majesty the Queen
  • The Legal 500: Tax (Tier 1)
  • International Tax Review
  • Who’s Who Legal: Osler lawyers recognized in Tax
  • Best Lawyers Canada: Recognized as "Law Firm of the Year" in the area of Tax Law (Canada), 2022

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