Corporate tax in Alberta: what the provincial layer adds

Alberta adds one return and subtracts two systems. Your corporation files the federal T2 with the CRA and a second corporate income tax return, the AT1, with Alberta’s Tax and Revenue Administration — because Alberta collects its own corporate tax rather than having the CRA collect it. Against that, there is no provincial sales tax and no provincial payroll levy. Sales tax stays 5% GST on one federal registration, and payroll stops at income tax withheld, CPP and EI.

Two returns, one set of books

Most provinces let the CRA collect their corporate tax under a federal-provincial collection agreement. One T2 goes in, the CRA assesses the federal and provincial tax together, and the province never appears as a separate filing. Alberta is not one of those provinces. It assesses its own corporate income tax, on its own return, through its own administrator: Tax and Revenue Administration, or TRA, a division of Alberta Treasury Board and Finance.

The AT1 starts from the same books as the T2. Alberta computes taxable income largely on the federal base, then applies its own rates on its own schedules and runs its own corporate credits, claimed with Alberta rather than on the T2. What differs is not the bookkeeping but the filing: two returns, two assessments, two notices, two accounts that can each fall behind on their own.

The rates themselves are layered, not alternative. Alberta sets a small-business rate on active business income up to a provincial business limit and a general rate on the rest, and both sit on top of the federal layer — 9% on the first C$500,000 of active business income for an eligible CCPC in 2026, with the general federal rate above that. Your corporation’s real rate is the federal number plus the Alberta number. Only the federal half is stated here; Alberta’s rates and its business limit move on provincial budgets.

The AT1 keeps its own calendar

The date that catches owners is not the AT1’s deadline. It is the assumption that Alberta’s dates are the CRA’s dates. Alberta sets the AT1’s filing deadline, its balance-due date and its instalment requirement under its own legislation, and enforces them with TRA’s own penalties and interest. Where instalments are required, they run on Alberta’s schedule alongside the federal ones. A missed federal instalment and a missed Alberta instalment are two separate problems with two separate bills.

Not every Alberta corporation has to file the AT1. Alberta exempts corporations meeting a set of conditions — broadly, no permanent establishment outside Alberta, taxable income under a limit, and no Alberta credits claimed for the year. The conditions are specific and the limit moves, so “we have never filed one” is worth confirming each year. The federal filing year is set out separately, and the deadline table flags that provincial filings, Alberta’s AT1 in particular, run on their own calendars.

Sales tax: 5% GST, and that is the layer

Alberta charges no provincial sales tax. A corporation selling in Alberta deals with one sales tax, one registration and one return — GST at 5%, federal, filed with the CRA on the reporting period your revenue and your elections set.

That simplicity is about where you sell, not where you sit. For goods, GST/HST generally follows the province the goods are delivered to, so an Alberta corporation shipping to an Ontario customer generally charges 13% HST on that sale, and one shipping into a province with its own retail sales tax may have to register there separately. The place-of-supply mechanics decide it.

The employer layer: WCB, and what is not there

Hiring in Alberta adds one provincial account, and it is not a tax. Employers with workers in Alberta generally register with Alberta’s Workers’ Compensation Board (WCB-Alberta) and pay premiums on assessable earnings, at a rate set by industry classification rather than by profit. Owners and directors are generally not automatically covered by the corporation’s account; personal coverage is a separate election.

There is no Alberta payroll levy. Ontario’s employer health tax, British Columbia’s, Quebec’s health services fund, the Manitoba and Newfoundland levies — none has an Alberta counterpart. So payroll stops at the federal obligations: income tax withheld, CPP, EI, remittances on the schedule your withholding size sets, and T4s by the last day of February.

When you operate in more than one province

A permanent establishment in another province — generally a fixed place of business, and in some cases an employee or agent with authority to contract — makes the corporation taxable in that province too. Income is then allocated among provinces generally by a formula weighting the gross revenue and the salaries and wages attributable to each establishment, computed on a federal schedule and carried into each province’s return.

For an Alberta corporation, expansion means additions, not replacements. The T2 and the AT1 stay. What arrives on top is a share of income taxed at another province’s rates, sales-tax registration where selling into that province triggers it, a workers’-compensation account wherever you have workers, and any payroll levy that province charges. It runs the other direction as well: a corporation based elsewhere that opens a permanent establishment in Alberta generally picks up the AT1.

The year at a glance for an Alberta corporation

Illustrative, on a December 31 year-end.

• The T2 with the CRA, six months after year-end — June 30 — with the balance generally due sooner.
• The AT1 with TRA, on Alberta’s own filing and payment dates, where a filing obligation exists.
• Instalments to the CRA, and separately to Alberta, where each is required.
• GST returns with the CRA at 5%, and no provincial sales tax return at all.
• T4 and T5 slips by the last day of February, with source deductions on your remitter schedule.
• WCB-Alberta’s payroll estimate and premiums, on the board’s own cycle.
• No provincial payroll levy return.

What Cadence does

We prepare the AT1 alongside the T2 from the same file, rather than remembering it in month seven, and set both instalment schedules at the start of the year instead of carrying last year’s forward. The WCB payroll estimate comes off the same numbers the T4s do. Where the corporation has establishments outside Alberta, the allocation gets decided before the year closes, while the answer can still change what you do rather than only the bill. Corporate returns, instalments and the provincial layer are business and corporate tax. Multi-jurisdiction filing is most of the work for carriers and owner-operators, whose trucks raise allocation questions a purely Alberta corporation never has to answer.