This article discusses the 2020 Dow Chemical Canada case. A downward transfer pricing adjustment is permitted under the Income Tax Act only if in their “opinion” the Canadian tax authorities determine that “the circumstances are such that it would be appropriate that the adjustment be made”. The question addressed in this case is whether the Tax Court of Canada rather than the Federal Court is the appropriate forum to review the exercise by the tax authorities of their authority to deny a downward adjustment. The Tax Court decided that it has that authority on the basis of the connection of the tax authorities’ opinion to the determination of a taxpayer’s assessable income under the Income Tax Act. This decision of the Tax Court of Canada may have implications beyond its immediate transfer pricing context for how decisions made by the Canada Revenue Agency in administering the Income Tax Act may be judicially reviewed.