Alberta corporate income tax is a provincial tax that every corporation with a permanent establishment in the province must pay on top of federal corporate tax. Alberta and Quebec are the only provinces that run their own corporate tax systems rather than letting the Canada Revenue Agency collect on their behalf, so an Alberta-based corporation files two returns: the federal T2 and the provincial AT1. Provincial rates are 2% for eligible small business income and 8% on general income, giving combined federal-provincial rates of 11% and 23% respectively.
Who Has to File in Alberta
Any corporation with a permanent establishment in Alberta at any point during its tax year must file under the Alberta Corporate Tax Act. That covers Canadian-resident corporations and foreign entities equally.1Government of Alberta. Alberta Corporate Tax Act
A permanent establishment is a fixed place of business: an office, branch, factory, workshop, warehouse, mine, oil well, farm, or timber land. Ownership isn’t required. Maintaining a business presence at the location is enough.2Government of Alberta. Alberta Corporate Income Tax CTIB-1R2 Taxability of a Corporation With an Alberta Permanent Establishment
A corporation without a physical location is still deemed to have a permanent establishment if it carries on business through an employee or agent with general authority to contract on its behalf, exercised repeatedly. Keeping a stock of merchandise in Alberta from which orders are regularly filled also triggers the filing obligation. Samples and display inventory alone do not.2Government of Alberta. Alberta Corporate Income Tax CTIB-1R2 Taxability of a Corporation With an Alberta Permanent Establishment
For U.S. corporations, the Canada-United States Income Tax Convention narrows the reach. Under Articles V and VII, a U.S. resident’s business profits are only taxable in Canada to the extent they are attributable to a permanent establishment in Canada.3Internal Revenue Service. United States – Canada Income Tax Convention
The Rates
Alberta applies two provincial rates:
- A 2% small business rate on the first $500,000 of active business income earned in Alberta by a Canadian-controlled private corporation (CCPC).
- An 8% general rate on income above that threshold and on corporations that don’t qualify as CCPCs.
The 8% general rate is the lowest provincial corporate rate in Canada.4Government of Alberta. Taxes and Levies Overview Federally, after the tax abatement and general tax reduction, the rate is 15% for most corporations and 9% on income eligible for the small business deduction.5Canada Revenue Agency. Corporation Tax Rates Combined, that produces 11% on the first $500,000 for a CCPC and 23% on general income.
Associated Corporations Share the $500,000 Limit
CCPCs in an associated group must divide the $500,000 small business threshold among themselves. Two related corporations each earning $400,000 cannot both claim the full limit; they allocate it, and the group total cannot exceed $500,000.6Alberta.ca. Corporate Income Tax
Allocating Income Across Provinces
A corporation operating in Alberta and elsewhere allocates taxable income to each province using a formula that averages two factors, each weighted equally: the share of gross revenue attributable to the Alberta permanent establishment, and the share of salaries and wages paid there.7Canada Revenue Agency. Income Tax Folio S4-F3-C2 Provincial Income Allocation Clean records separating revenue by province and tracking where each employee works are what make this defensible on audit.
Filing the AT1 Return
The provincial return is Form AT1, the Alberta Corporate Income Tax Return. You need your Alberta Corporate Account Number, a nine-digit identifier, to file. The AT1 calculation parallels the federal T2, though corporations can claim different discretionary deductions provincially, including different capital cost allowance amounts.6Alberta.ca. Corporate Income Tax
For tax years beginning on or after January 1, 2025, electronic filing through Net File is mandatory for most corporations. Paper filing is available only for insurance corporations, non-resident corporations, corporations reporting in functional currency, and corporations exempt under section 35 of the Alberta Corporate Tax Act.8Government of Alberta. Alberta Corporate Tax Act Software Certified for AT1 Returns
The AT1 is due six months after fiscal year-end. A December 31 year-end means a June 30 filing deadline. Multi-province corporations include allocation details showing Alberta gross revenue and wages against their totals, and Schedule 1 handles adjustments to net income for items like charitable donations and provincial tax credits.
When to Pay
The payment deadline is separate from the filing deadline and comes sooner. Most corporations pay their Alberta balance within two months of fiscal year-end. Eligible CCPCs get a third month.6Alberta.ca. Corporate Income Tax
A CCPC qualifies for the three-month window if it meets any one of these tests:
- It claims the Alberta small business deduction and has taxable income of $500,000 or less in the current tax year.
- It claimed the Alberta small business deduction and had taxable income of $500,000 or less in the immediately preceding tax year.
- Its Alberta corporate income tax payable for the current year, or its first instalment base, is $2,000 or less.
Non-CCPC corporations pay within two months. Any corporation whose Alberta tax payable or first instalment base is $2,000 or less is exempt from installments and simply pays the full amount by the balance-due day.6Alberta.ca. Corporate Income Tax
Corporations that aren’t exempt pay in equal monthly installments due on the last day of each month during the tax year, with any remaining balance due by the balance-due day. A new corporation (other than one formed by amalgamation) is not required to pay installments in its first tax year.6Alberta.ca. Corporate Income Tax
Late Filing Penalties and Interest
A late AT1 attracts a penalty of 5% of the unpaid tax at the filing deadline, plus 1% for each complete month the return remains outstanding, up to 12 additional months. A return a full year overdue can be hit for 17% of the unpaid balance.9Government of Alberta. Alberta Corporate Income Tax CT-4R7 Interest and Penalties
Overdue balances also accrue interest. Alberta’s prescribed debit interest rate for corporate tax is 7.0% as of early 2026. The rate is set quarterly and can move during the year.10Alberta.ca. Tax, Levy, and Prescribed Interest Rates
Provincial Tax Credits
Alberta offers provincial credits that reduce corporate tax beyond what’s available federally. Two carry the most weight.
Innovation Employment Grant
The grant provides 8% on eligible R&D spending up to the corporation’s base level, which is the average qualifying R&D spending over the previous two years, and an enhanced 20% on spending above that base. Maximum eligible annual spending is $4 million. Eligible expenditures must match those that qualify for the federal Scientific Research and Experimental Development program.11Alberta.ca. Innovation Employment Grant
Agri-Processing Investment Tax Credit
Corporations or registered partnerships investing at least $10 million in a value-added agri-processing facility in Alberta can claim a 12% non-refundable, non-transferable credit on eligible capital investment. The credit is claimed over time: up to 20% of the total in year one, up to 30% in year two, and up to 50% in year three, with any remainder claimable over the following seven years for a 10-year total window.12Alberta.ca. Alberta Agri-Processing Investment Tax Credit
Record Retention
Books, records, and supporting documents must be kept for six years from the end of the last tax year they relate to. That covers general ledgers, contracts, bank statements, and sales receipts. Destroying records before that period ends, or failing to produce them on audit, can result in penalties and unfavorable assumptions about what the missing records would have shown.