CRA T2, Revenu Québec CO-17 and Alberta AT1 Corporate Tax Returns: Key Differences Canadian Corporations Should Know
In Canada, most corporations file a T2 Corporation Income Tax Return with the Canada Revenue Agency (CRA), and that return generally calculates both federal corporate tax and provincial or territorial corporate tax.
For a broader overview of Canadian corporate tax obligations, see our Corporate Tax Return in Canada Complete Guide.
Why Québec and Alberta Corporate Tax Filings Are Different
Québec and Alberta are different.
A corporation with a permanent establishment in Québec generally has to file a separate Québec corporate income tax return, the CO-17, with Revenu Québec. A corporation with a permanent establishment in Alberta generally has to file a separate Alberta corporate income tax return, the AT1, with Alberta Tax and Revenue Administration.
This distinction matters because a corporation in Québec or Alberta cannot assume that filing the federal T2 completes all of its corporate tax obligations. It may also have separate provincial filing, payment, instalment, tax credit and administrative requirements.
The CRA T2 Return: The Federal Starting Point
The T2 Corporation Income Tax Return is the federal corporate tax return for Canadian corporations. It reports taxable income, calculates federal income tax, tracks losses, reports dividends, claims deductions and tax credits, and includes supporting schedules such as the General Index of Financial Information (GIFI).
In most provinces and territories, the T2 also calculates provincial or territorial corporate tax. Québec and Alberta are the main exceptions because they administer their own corporate income tax systems.
For Canadian-controlled private corporations that qualify for the small business deduction, the federal small business tax rate is generally 9% on eligible active business income. The general federal corporate tax rate, after the general tax reduction, is generally 15%.
If you need a detailed explanation of corporate tax rates across Canada, see Corporate Federal and Provincial Tax Rates in Canada.
The Québec CO-17: A Separate Provincial Corporate Tax Return
The CO-17 – Corporation Income Tax Return is Québec’s provincial corporate income tax return. A corporation carrying on business in Québec or having a permanent establishment in Québec generally has to file a CO-17 in addition to its federal T2.
Although much of the accounting information may be similar, the CO-17 applies Québec tax rules. Some Québec rules are harmonized with federal tax rules, but others are not. Québec has its own provincial credits, its own administrative forms, its own instalment rules and its own payment accounts.
The CO-17 should not be treated as a simple duplicate of the T2. The figures must be consistent, but the provincial adjustments, credits, deductions and payment rules must be reviewed separately.
The Alberta AT1: A Separate Return for Corporations with an Alberta Permanent Establishment
The AT1 – Alberta Corporate Income Tax Return is Alberta’s separate provincial corporate income tax return. A corporation with a permanent establishment in Alberta generally has to file an AT1, even if it was incorporated outside Alberta.
The Alberta AT1 is filed with Alberta Tax and Revenue Administration, not with the CRA. Alberta has its own payment system, corporate account requirements, electronic filing rules, instalment rules and provincial tax credits.
Difference No. 1: Separate Provincial Returns in Québec and Alberta
In most provinces, the T2 filed with the CRA handles both federal and provincial corporate income tax. In Québec and Alberta, the provincial return is separate.
- Federal: T2 – CRA
- Québec: CO-17 – Revenu Québec
- Alberta: AT1 – Alberta Tax and Revenue Administration
Difference No. 2: Filing Deadlines vs. Payment Deadlines
The federal T2 is generally due within six months after the end of the corporation’s tax year. The Québec CO-17 and Alberta AT1 generally follow the same six-month filing deadline.
However, tax balances are often due earlier than the filing deadline. Corporations can incur interest even when returns are filed on time if taxes were not paid by the applicable balance-due date.
For additional guidance, see Corporate Tax Filing Deadlines Canada.
Difference No. 3: Balance-Due Dates Must Be Reviewed Separately
Federal balances are generally due two months after year-end, although certain eligible CCPCs may qualify for a three-month deadline.
Québec balances are generally due within two months after year-end.
Alberta balances are generally due by the end of the second month following year-end, with certain eligible CCPCs qualifying for a three-month payment deadline.
Difference No. 4: Instalments Are Separate by Tax Authority
Federal instalments are paid to the CRA.
Québec instalments are paid separately to Revenu Québec.
Alberta instalments are paid separately to Alberta Tax and Revenue Administration.
Corporations operating in Québec or Alberta must track both federal and provincial instalments independently.
Difference No. 5: Provincial Tax Rates Differ
Québec’s general corporate tax rate is 11.5%. The small business rate was 3.2% and is reduced to 2.2% for taxation years beginning after April 29, 2026.
Alberta’s general corporate income tax rate is 8%, and its small business rate is 2%, making Alberta one of the lowest-tax jurisdictions in Canada for corporate income tax purposes.
Difference No. 6: Provincial Tax Credits Are Different
Québec offers numerous provincial credits related to research and development, technology, multimedia, training, cultural industries and investment activities.
Alberta also offers provincial incentives related to innovation, research, agri-processing and targeted economic sectors.
Difference No. 7: Electronic Filing and Payment Systems Differ
CRA systems are used for T2 filing and payments.
Revenu Québec administers CO-17 filing, payments and communications separately from the CRA.
Alberta administers AT1 filing and payments through its own systems, including TRACS where applicable.
What Corporations Should Remember
A Québec corporation generally requires both a T2 and a CO-17. An Alberta corporation generally requires both a T2 and an AT1. Corporations operating in multiple provinces may also require interprovincial allocation schedules and additional compliance reviews.
Businesses that need assistance preparing or submitting returns can review our guides on How to File a T2 Corporate Tax Return and CRA Penalties for Late Corporate Tax Filing.
Conclusion
The CRA T2, Revenu Québec CO-17 and Alberta AT1 all report corporate income tax, but they do not operate in the same way.
Québec and Alberta require separate provincial corporate tax returns, separate payments and separate attention to local rules. Proper coordination between federal and provincial filings helps avoid reporting errors, interest charges and penalties.
