If you run an incorporated business in Ontario, a single line in this year's provincial budget is worth more to your bottom line than most of the headlines around it. Starting July 1, 2026, Ontario cut its small business corporate income tax rate from 3.2% to 2.2% — a reduction of more than 30% — and raised the amount of income eligible for that rate from $500,000 to $600,000. The province says it will deliver $1.1 billion in relief to more than 375,000 small businesses over the next three years.
That's the announcement. What actually matters for an incorporated freelancer, consultant, or small CCPC owner is messier: a mid-year rate change means a blended tax rate for anyone with a calendar year-end, a new $100,000 band where federal and provincial limits no longer line up, and a set of planning moves that only work if you make them before your fiscal year closes. Here's what changed, why the fine print matters more than the headline number, and what to check before December 31.
The Basic Change: 3.2% to 2.2%
Ontario's small business deduction (SBD) rate applies to the first slice of active business income earned by an eligible Canadian-controlled private corporation (CCPC). Combined with the federal small business rate of 9%, here's how the math moves:
| Before July 1, 2026 | After July 1, 2026 | |
|---|---|---|
| Ontario small business rate | 3.2% | 2.2% |
| Federal small business rate | 9% | 9% |
| Combined rate | 12.2% | 11.2% |
| Income eligible at this rate (Ontario) | First $500,000 | First $600,000 |
For a corporation already earning $500,000 of active business income, the one-point rate cut alone is worth up to $5,000 a year once it's fully phased in. Combined with the $100,000 increase in the eligible income band, an Ontario CCPC pulling in $600,000 of active business income could save considerably more than that once the transition period ends.
It's a real, permanent cut — not a temporary credit or a rebate that needs to be claimed. But "effective July 1" is where the simple story ends.
The Proration Wrinkle Nobody Mentions
Corporate tax rates don't reset on a calendar. If your corporation's fiscal year straddles July 1, 2026 — which describes almost every business with a December 31 year-end — the CRA requires you to prorate the rate change based on the number of days in each period.
For a typical calendar-year CCPC, that works out to roughly 3.2% for the January–June portion and 2.2% for the July–December portion, blending to an effective Ontario small business rate of about 2.7% for the 2026 tax year (a combined federal-provincial rate near 11.7%). You don't get the full 11.2% combined rate until your first complete fiscal year that starts on or after July 1, 2026 — for most businesses, that's the 2027 tax year.
If your corporate tax software or bookkeeper hands you a flat 2.2% assumption for all of 2026, that number is wrong for anyone whose year-end isn't June 30. It's a small discrepancy in percentage terms, but it's exactly the kind of rounding error that turns into a mismatched installment payment or an unpleasant surprise at filing time.
The New $100,000 Gap Between Federal and Provincial Limits
This is the part of the change that's easy to miss entirely. The federal small business limit — the income ceiling for the 9% federal small business rate — stays at $500,000. It did not move. Only Ontario's provincial limit rose, to $600,000.
That mismatch creates a band of income, between $500,000 and $600,000, where the two levels of government now disagree about what counts as "small business" income:
- First $500,000: qualifies for both the federal small business rate (9%) and Ontario's small business rate (2.2%) — combined 11.2%.
- $500,000 to $600,000: no longer qualifies for the federal small business rate, so it's taxed at the federal general rate (15%) — but still gets Ontario's small business rate (2.2%). Combined: 17.2%.
- Above $600,000: taxed at both general rates — the full 26.5% combined.
So a CCPC earning $600,000 in active business income after July 1, 2026 doesn't pay one blended rate — it pays 11.2% on the first $500,000 and a distinct 17.2% on the next $100,000. That $100,000 gap band is a genuinely new bracket that didn't exist before this budget, and it's easy for planning software built around the old $500,000-for-everything assumption to get wrong.
Passive Income Can Shrink Your Limit Before Any of This Applies
None of the above matters if your corporation has already lost part of its small business deduction to the passive income grind. Since 2019, a CCPC's small business limit shrinks by $5 for every $1 of "adjusted aggregate investment income" (AAII) above $50,000 earned in the prior tax year, disappearing completely once that prior year's passive income hits $150,000.
AAII captures most of what a corporation earns from a non-registered investment portfolio — interest, portfolio dividends, and taxable capital gains — but not income inside an RRSP or income from the active business itself. If your corporation parked retained earnings in a brokerage account and had a strong year for capital gains in 2025, your 2026 small business limit could already be reduced before you apply any of the new Ontario numbers. Check last year's AAII before assuming you'll get the full benefit of either the $500,000 federal or $600,000 Ontario limit.
If You Have More Than One Corporation, You're Sharing the Limit
Associated corporations — companies connected through common ownership or the Income Tax Act's related-party rules — don't each get their own small business limit. They share one $500,000 federal limit (and, going forward, one $600,000 Ontario limit) across the whole group, divided however the corporations agree via an annual Schedule 23 filing. Miss that filing and the CRA defaults every associated corporation's share of the limit to zero, pushing all their active income to the general rate.
This trips up incorporated professionals more often than you'd expect: a consultant with an operating company and a separate holding company, or spouses who each incorporated and hold small cross-shareholdings in each other's businesses, can be deemed "associated" without realizing it. If you've set up more than one corporation for liability or income-splitting reasons, confirm the association analysis and the Schedule 23 allocation before year-end — this is worth a conversation with an accountant, not a guess.
Before Your Fiscal Year Closes: A Checklist
- Confirm your fiscal year-end and calculate your actual proration. Don't assume a flat 2.2% or 11.2% for 2026 unless your year-end is June 30.
- Check last year's AAII. If your corporation's passive investment income exceeded $50,000 last year, your small business limit is already reduced this year — model the real number, not the statutory maximum.
- Review associated-corporation status and file Schedule 23 if you or your spouse hold more than one corporation.
- Model the $500,000–$600,000 gap band if your active business income is approaching or above $500,000 — that next $100,000 is taxed at 17.2%, not 11.2% or 26.5%, and it changes the math on whether to accelerate or defer income.
- Revisit your salary-versus-dividend mix. A lower small business rate slightly changes the corporate-personal tax integration math that determines whether paying yourself salary or dividends (or some mix) is more efficient this year.
None of these five items is optional bookkeeping busywork — they're the difference between actually capturing the savings this budget promised and quietly overpaying because your year-end assumptions didn't get updated.
Why This Is a Bookkeeping Problem, Not Just a Tax Problem
Every item on that checklist depends on having clean, dated records of active business income, passive investment income, and related-party structure available when you need them — not reconstructed from bank statements in March. A mid-year rate change is exactly the kind of event that exposes sloppy books: if your ledger doesn't cleanly separate income earned before and after July 1, or active business income from portfolio returns, prorating correctly becomes a guessing game instead of a calculation.
Plain-text accounting makes this specific problem easy, because every transaction carries a real date and every account is explicit. A query for "active business income booked after 2026-07-01" or "portfolio interest and capital gains for the 2025 tax year" is a filter, not a spreadsheet reconstruction project.
Keep Your Books Ready for the Next Rate Change
Tax rates change on government timelines, not fiscal year-ends, and the businesses that benefit are the ones whose records were already clean enough to model the change quickly. Beancount.io gives you plain-text, version-controlled accounting where every transaction is auditable by date and category — see how it works in the docs or explore your numbers visually with Fava. Get started for free and be ready for whatever the next budget brings.