Michael Colborne
Toronto Office

Michael Colborne


Michael Colborne received his LL.B. from the University of Manitoba and a LL.M (U.S. tax) from New York University.

After clerking at the Federal Court of Canada, Michael joined Thorsteinssons LLP and became a partner in 2005. He has been called to the Bar in Ontario and British Columbia. Michael is the managing partner of Thorsteinssons LLP.

Michael’s practice focuses on corporate and international tax planning, regularly advising Canadian and foreign-based multi-national groups on a variety of matters, including financing, mergers and acquisitions, and natural resource taxation. He also has considerable experience in handling tax controversy issues in Canada and a number of other countries. In this regard, Michael has appeared in the Supreme Court of Canada, Federal Court of Appeal, Tax Court of Canada, the superior courts of British Columbia and Ontario, and the Revenue Tribunal of the United Republic of Tanzania.

Over the past 20 years Michael has developed a widely-recognized expertise in issues involving the mining industry, and regularly advises a number of Canadian and foreign-based multinational mining companies. In addition to his transactional experience (which has involved everything from complex acquisitions and divestitures to metal stream financing transactions), Michael has counseled both taxpayers and governments on legislative and tax policy matters relating to the mining industry.

Michael also acts for a number of large multi-national companies in a broad range of industries including aerospace and defence, paper and household products, pharmaceuticals, financial services, nuclear and hydro power, and real estate.

Michael speaks and writes frequently on international and mining tax matters, presents numerous papers for the Canadian Tax Foundation, International Fiscal Association, International Bar Association and Rocky Mountain Mineral Law Foundation.  He is on the editorial boards of the CCH Income Tax Act and the Resource Sector Taxation and International Tax Planning Journals.

In 2007 Michael was named one of the leading lawyers under 40 in Canada by Lexpert magazine, and he is recognized in numerous industry publications such as Chambers and Lexpert. He is a former Governor of the Canadian Tax Foundation.