Mississauga is full of incorporated businesses, from the logistics yards around Pearson to dental offices, distributors and second-generation family manufacturers. Whatever they do, they all hit the same layered tax system. There’s federal corporate tax, Ontario corporate tax, and a handful of provincial filings that sit next to the main return. Here’s how the layers fit together, and what a Mississauga corporation has to file each year.
One Return for Two Governments
The Canada Revenue Agency has run Ontario’s corporate income tax since 2009. So an Ontario corporation files one T2 with the CRA, and it covers both federal and Ontario tax. The Ontario-specific math happens on Ontario schedules attached to the T2 (the Ontario corporation tax calculation, for example), and whatever is owed to either government gets paid to the CRA in one go.
It’s a lot simpler than it used to be. The flip side is that a mistake on the provincial portion travels with the federal return.
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The Rates That Apply
Odds are good your company’s a CCPC (a Canadian-controlled private corporation, to give it the full mouthful), and if so, the small business deduction applies to the first $500,000 of active business income. Which is the whole ballgame, rate-wise. Roughly:
- Federal: 9% on the part that gets the small business deduction, 15% (the general rate) on anything past it.
- Ontario: 2.2% on the small business slice since July 1, 2026, down from 3.2% (years that straddle the date land somewhere in between, prorated), and 11.5% on the rest.
For a full year after the change, qualifying income in Ontario faces a combined small business rate of 11.2%. Income over the business limit is taxed at the combined general rate.
One quirk worth knowing. Federally, a corporation’s small business limit gets ground down once its passive investment income passes $50,000. Ontario never adopted that rule. A Mississauga company sitting on a big investment portfolio can therefore lose some of the federal deduction while the Ontario lower rate stays fully intact.
Allocating Income Between Provinces
Plenty of Mississauga businesses reach past Ontario: a warehouse in Alberta, staff in Quebec, a branch in B.C. A corporation with a permanent establishment in more than one province has to split its taxable income among them, usually by a formula based on the salaries and gross revenue tied to each establishment. The split decides how much tax each province gets, so it has to be right.
Filing and Payment Deadlines
- T2 filing: within six months of the tax year-end.
- Balance owing: within two months of year-end, or three months for CCPCs that meet the small business conditions.
- Instalments: generally required if total tax payable topped $3,000 in the current or previous year. They’re paid monthly, or quarterly for qualifying small CCPCs.
Most corporations are now required to file the T2 electronically, using CRA-certified software.
Ontario Filings Outside the T2
Ontario Annual Return
Every year, an Ontario corporation also has to confirm details like its directors and registered office by filing an annual return with the Ontario Business Registry. It’s separate from the T2, with its own due date tied to the anniversary of incorporation. Keep missing it and the province can eventually dissolve the corporation administratively.
Employer Health Tax
If you have staff in Ontario, Employer Health Tax (EHT) is charged on that payroll. Eligible private-sector employers are exempt on their first $1 million of annual Ontario remuneration, and associated employers share that exemption. Employers over the exemption, or who have to file for other reasons, generally file an annual return by March 15. Plenty of smaller Mississauga firms never get near that number. If you’re hiring quickly, though, watch it.
GST/HST
HST in Ontario is 13%, and it goes to the CRA like everything else. How often you file (monthly, quarterly, annually) hinges on your sales and on which reporting period you’ve chosen.
Ontario Tax Credits Worth Knowing
A number of Ontario credits are claimed through the T2. Growing companies most often run into the Ontario Innovation Tax Credit, which rewards qualifying R&D and pairs with the federal SR&ED program. There are others for apprenticeship training and for certain media and production work. Each has detailed eligibility rules. Check them against your own facts; don’t assume you qualify.
Common Issues for Mississauga Corporations
- Associated corporations: own two or three companies and they’ll usually split one $500,000 limit, with schedules to match.
- Transportation businesses: a trucking or logistics company with a big fleet has a lot riding on capital cost allowance and on how income is allocated between provinces.
- Owner-operators: an incorporated driver who hauls only for one carrier can look, to the CRA, like a personal services business, and that classification is expensive enough that you’ll want advice before it ever comes up.
- Straddling the July 2026 rate change: a March 31, 2027 year-end, for example, has three months before the cut and nine after; the Ontario rate gets prorated, and instalments set on the old rate may now be too high.
In practice, most owners face the same federal and Ontario rules, just applied to their own facts. When you’re choosing who prepares your corporate tax return Mississauga, care less about where they’re located and more about how well they know the Ontario schedules, the allocation rules and the deadlines that run alongside the T2.
Conclusion
So: one T2, Ontario schedules attached, both governments paid through the CRA. Off to the side you’ve got the Ontario annual return, Employer Health Tax if your payroll’s big enough, and HST. With the small business rate cut in 2026, this year’s a good one to sit down and check that your rate, instalments and filings all line up.
Frequently Asked Questions
Do Ontario corporations file a separate provincial tax return?
No. Since 2009, Ontario corporate income tax has been reported on the federal T2 with Ontario schedules and administered by the CRA.
What is the small business tax rate in Ontario?
It’s 2.2% provincially since July 1, 2026 (it was 3.2%). Add the 9% federal rate and you get 11.2% for full years after the change.
Is the Ontario annual return the same as the T2?
No. It’s a separate filing, through the Ontario Business Registry, that updates corporate information.
Does my business have to pay Employer Health Tax?
Eligible employers are exempt on their first $1 million of Ontario payroll. Past that, EHT applies, and an annual return is generally required.
