The Corporate Income Tax in Canada: Does its Past Foretell its Future?
Authors: Bird Richard M. , Wilson Thomas A. 
Published: January 2025

Corporate tax reform has long been a contentious issue in Canada. Official commissions, academics and others have often proposed changes in the way we tax corporations. During the last 30 years, perhaps largely owing to concerns about international competitiveness, the corporate tax rate has been substantially reduced. Since revenues did not decline as a result, those concerned by increased inequality who believe that corporate taxes are paid mainly by the rich have suggested that corporate rates should be increased. Others, more persuaded by the increasing evidence that much of the burden of the corporate tax ultimately falls on workers and wages and that even to the extent it falls on capital the economic price paid in terms of reduced output and productivity for each corporate tax dollar collected is high have taken the opposite tack and argued that, if anything, corporate tax reform should be aimed at reducing even further the effective tax rate on corporate capital. Both the technical and the political aspects of corporate taxation are thus at play in the current discussion of possible corporate tax reform. After a brief review of the history, we consider what is now known about the relation between corporate rates and revenue, the surprisingly complex question of who ultimately pays the tax, and the largely undesirable economic effects of corporate income taxes. If all voters were economists and familiar with the evidence, it is unlikely any would favour big increases in corporate taxes. However, even economists who have read all the studies mentioned here (and more) do not agree about the best way to reform the corporate income tax. We sketch three recent major reform proposals Canadian experts have recently put forward (1) replace the existing corporate tax by a tax on ‘rents’ (above-normal returns on capital), (2) replace both it and the current personal income tax by a ‘dual income tax’ with a flat rate on all capital income (corporate and personal), or (3) adopt a more gradual approach to reform that would broadly keep the present system but make it more uniform in its treatment of investment. On the whole, we suggest that, although the ‘rent’ proposal is clearly the favourite in the academic horse race, and we think a much closer look should be taken at the second (dual income tax), the more incremental third proposal – improve what we now have – is perhaps not only the way we should go now but is also likely to be the politically most acceptable of these schemes. Finally, since one reason corporate tax reform is so difficult is because it is closely related to a number of other issues that are often both technically complex and politically sensitive, we consider several such issues. Some, such as small business taxation, could be reformed independently of the sorts of more general reforms just mentioned. We sketch several reforms that would simplify the system, maintain some incentive for small businesses and reduce the extent to which the current system provides a shelter for the rich. But other issues cannot be dealt with separately. What is the appropriate level and nature of ‘integration’ between the corporate and personal income taxes? What is the appropriate role of federal and provincial governments with respect to the corporate income tax? And, assuming that we continue to use taxes to provide preferences (incentives) to specific sectors and activities, what is the best way in which to do so? Within entering too far in the ‘dismal swamp’ of the inner workings of the tax system, we suggest some possible directions for reform in these areas such as a ‘sunset’ clause for tax preferences to reduce the likelihood that they will be indefinitely preserved whether socially useful or not.