Mark Tonkovich 2818

Mark Tonkovich

Baker & McKenzie LLP


Mark Tonkovich is a partner in Baker McKenzie's Toronto Tax Practice Group and a member of the Firm's North America Tax Controversy Steering Committee. He practices exclusively in the tax controversy field. The Canadian Federal Court of Appeal commented on his work as follows in a 2013 judicial review application: "In exemplary fashion, Mr. Tonkovich untangled a confusing body of evidence and argument, discerned the most important legal issues, and effectively presented submissions that were of significant assistance to the Court in the efficient resolution of this case."

Prior to joining the Firm, Mr. Tonkovich was a government tax litigator with the Department of Justice and a judicial clerk at the Federal Court of Appeal. He held a Lord Beaverbrook Scholarship in Law and received several academic awards in the course of his legal studies, including prizes in corporate law & taxation and administrative law. He has published in Canada's leading peer-reviewed journals on taxation law and on constitutional law, and he regularly speaks at events for tax professionals.

Practice Focus

Mr. Tonkovich helps clients resolve all manner of tax and related public law disputes with the Canada Revenue Agency and provincial tax authorities. He works on all aspects of the dispute resolution process, including the analysis of tax assessment and litigation risks, disclosure and negotiation with government agencies, audit management and defence, administrative appeals, and litigation in federal and provincial courts. He has successfully represented clients in the Tax Court of Canada, the Federal Court, the Federal Court of Appeal, the Ontario Superior Court of Justice, the Court of Appeal for Ontario, and in resisting leave to appeal to the Supreme Court of Canada.

Representative Legal Matters

  • Acted for taxpayers in appellate-­level cases concerning the general anti­-avoidance rule (GAAR) and employer­ provided taxable benefits.
  • Acted for taxpayers in trial­-level tax disputes concerning the provincial GAAR, taxation of foreign affiliates in the offshore banking industry, the scientific research and experimental development (SR&ED) tax incentive program, characterization of foreign legal entities, and the tax consequences of employee/shareholder fraud.
  • Acted for taxpayers in applications for judicial review concerning the refusal to provide relief from double taxation under the Canada­-US Tax Treaty, the failure to issue timely assessments of federal income tax, and the intersection of employment insurance and bankruptcy law.
  • Acted for taxpayers in administrative appeals relating to foreign affiliates, transfer pricing, non-resident withholding tax, debt forgiveness, sales tax, and the scope and validity of provincial income tax assessments.
  • Acted for taxpayers in rectification proceedings to correct substantial transactional errors in a cross-­border hybrid refinancing plan.
  • Guided clients through a large number of tax audits, including several reviews by the CRA’s Aggressive Tax Planning Section, as well as in applications for taxpayer relief and voluntary disclosure.

Professional Associations and Memberships

  • Ontario Bar Association - Chair of Section on Taxation Law
  • Canadian Tax Foundation - Member (Past: Toronto YP Steering Committee)
  • Halton County Law Association - Member
  • International Fiscal Association - Member
  • Philip C. Jessup International Law Moot Court Competition - Volunteer Judge
  • The Advocates' Society - Member


  • Ontario~Canada (2009)


  • Osgoode Hall Law School (LL.M. Tax) (2014)
  • University of New Brunswick (LL.B. Distinction) (2008)
  • University of Guelph (B.A. Dean's Honour List) (2005)


  • Croatian
  • English
  • Ukrainian