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This is a photo of Jeff Oldewening




Contact by email at [email protected]

t. 416-601-7778


Law School

University of Western Ontario

Bar Admission

Ontario, 2006

A recognized leader in corporate and cross-border tax law, Jeff helps clients navigate complex transactions and reorganizations

Jeff is a Partner in the Firm’s National Tax Group in Toronto with a practice focusing on domestic and cross-border mergers & acquisitions and reorganizations.  He develops success-driven tax planning structures.

Jeff is an experienced senior tax practitioner, renowned for developing innovative tax planning structures. He has extensive experience guiding clients through complex domestic and cross-border M&A transactions, reorganizations and investments. He is one of the leading tax advisors in Canada in the area of corporate reorganizations and butterfly transactions. 

Jeff frequently acts for clients across a range of industry groups. Jeff teaches butterfly transactions at the Tax Law for Lawyers course and previously lectured on capital gains stripping at the In-Depth Tax Course for CPA Canada.  He is a member of the editorial board for the International Tax Planning journal, and a contributor to the Canadian Tax Journal.

Jeff has advised on the Canadian tax aspects of a variety of deals and reorganizations, including the following notable transactions:

  • UnitedHealth Group, in connection with its acquisition of Catamaran Corporation for US$12.8 billion;
  • Burger King Worldwide, in connection with its acquisition of Tim Hortons Inc. for US$12.5 billion, the U.S. tax inversion of Burger King under Restaurant Brands International Inc., the related financing, which involved a US$3 billion preferred equity investment from Berkshire Hathaway Inc., a secured US$7.25 billion credit facility and a private placement of US$2.25 billion of second lien secured notes, and an associated tender offer for Tim Hortons' outstanding US$1.2 billion of debt securities;
  • Lithium Americas Corp., as special tax counsel, in connection with its C$4.75 billion “butterfly” spin-off of Lithium Americas (Argentina) Corp., including an equity subscription by General Motors of US$970 million;
  • Rio Tinto, in connection with its US$3.3 billion take-private acquisition of Turquoise Hill Resources;
    • M&A Deal of the Year at the Canadian Law Awards;
  • Toronto-Dominion Bank, in connection with its C$80 billion Global Legislative Covered Bond programme;
  • Canadian Imperial Bank of Commerce, in connection with its US$40 billion Medium Term Note programme; and
  • Chrysler, in respect of its bankruptcy and restructuring.

Awards & Rankings

The Douglas J. Sherbaniuk Distinguished Writing Award in respect of the paper cited as Jeff Oldewening, Rachel A. Gold and Chris Sheridan, “Statutory Ratification” (2016) 64:1 Canadian Tax Journal 293-325.  The Canadian Tax Foundation confers this honour for the best writing undertaken for the Canadian Tax Foundation every year.