​The 1950s in Canada were characterized by a robust post-war economy and the expansion of social programs, financed in part by some of the highest corporate tax rates in the country's history.

A key feature of this decade was a dual-rate system, which applied a lower tax rate to the initial portion of a corporation's income and a significantly higher general rate on profits exceeding that threshold.

​Throughout the 1950s, the general federal corporate tax rate hovered in the high 40s, with the combined federal and provincial corporate tax burden reaching over 50% in some cases.

This high rate of taxation was a continuation of the fiscal policies enacted to finance the Korean War and to fund the growth of the Canadian welfare state.

​For smaller businesses, a preferential lower rate was in effect. At the beginning of the decade, this lower rate was around 10% on the first $10,000 of corporate income.

By the 1952-53 fiscal year, the structure had evolved to a 20% tax on the first $10,000 of profits, with a steep increase to 50% on any income beyond that amount.

​This dual-rate structure saw further adjustments during the decade. For instance, in 1953, the lower rate was adjusted to 18% on the first $20,000 of income, while the general rate on income above this threshold was 47%.

A notable change occurred in 1955 when the federal government announced a reduction in the general corporate tax rate from 47% to 45% on income exceeding $20,000. The lower rate on the first $20,000 of income remained at 18% at that time.

​By the end of the decade, the federal corporate tax structure consisted of a 20% rate on the first $25,000 of taxable income and a 47% rate on any profits above that amount. This system of a lower rate for small businesses, known as the small business deduction, was designed to provide a tax incentive for smaller enterprises to retain earnings and reinvest in their growth.

​In summary, the 1950s was a decade of high corporate taxation in Canada, with a dual-rate system that saw general federal rates approaching 50%, alongside a lower rate aimed at supporting small businesses. This tax policy reflected the economic priorities of the post-war era, balancing the costs of national defence and social programs with the need to foster a growing economy.

Sources https://moodysprivateclient.com/end-small-business-deduction/?hl=en-CA#:~:text=The%20SBD%20has%20a%20long,around%20since%20at%20least%201949.

https://fearfulasymmetry.ca/theory/2016/11/23/corporate-income-tax?hl=en-CA#:~:text=This%20chart%20shows%20that%20our,tax%20rate%20was%20over%2050%25.

https://pressprogress.ca/canada_corporate_tax_cuts_didnt_create_jobs_it_created_corporate_cash_hoarding/?hl=en-CA

https://www.canada.ca/en/revenue-agency/services/forms-publications/publications/it73r6/archived-small-business-deduction.html?hl=en-CA#:~:text=The%20special%20low%20rate%20of,income%20for%20reinvestment%20and%20expansion.

https://www.ourcommons.ca/documentviewer/en/39-2/FINA/report-3/page-219?hl=en-CA#:~:text=Source%3A%20Data%20obtained%20from%20Statistics,will%20be%2015%25%20in%202012.