The Small Business Deduction, fully explained
Canada's most valuable tax benefit for incorporated businesses. How it works, who qualifies, and the gotchas.
Published January 29, 2025 · 7 min read
The Small Business Deduction (SBD) is the single most valuable tax benefit available to Canadian incorporated businesses. It reduces the federal corporate tax rate from 15 percent to 9 percent on the first $500,000 of active business income. That is a 6 percent savings on every dollar of profit up to half a million dollars.
Who qualifies
You must be a Canadian-Controlled Private Corporation (CCPC). That means a corporation that is incorporated in Canada, is not publicly traded, and is not controlled by non-resident persons or public corporations.
If you are a sole proprietor or partnership, this does not apply to you. The SBD is exclusively for corporations.
What income qualifies
Active business income. Revenue from the actual operation of your business: selling products, providing services, doing work. Not passive investment income.
Investment income gets taxed at the higher general rate. Rental income usually counts as passive unless you are running a serious property business with five or more full-time employees.
The taxable capital phase-out
Here is where it gets technical. The full $500,000 SBD limit phases out as your corporation's taxable capital exceeds $10 million. Above $15 million in taxable capital, you lose the SBD entirely.
For most small businesses this is irrelevant. You would have to be reasonably substantial before you hit the threshold. But if you are growing fast, this is something to watch with your accountant.
The passive income reduction
Recently changed rules also phase out the SBD if your corporation earns significant passive investment income. Specifically, if your adjusted aggregate investment income exceeds $50,000, the SBD limit reduces by $5 for every dollar over.
The fix, if you have meaningful passive income building up, is to hold investments in a holding company instead of your operating company. This is a conversation for your accountant.
Provincial stacking
Most provinces offer their own version of the SBD that stacks on top. Combined federal and provincial rates can be as low as 9 to 12 percent depending on your province, versus general corporate rates of 25 to 27 percent.
On $500,000 of qualifying income, that is the difference between paying $45,000 in tax and paying $130,000. A staggering difference. Almost nobody realizes the SBD is worth this much.
How to claim it
File your T2 corporate tax return. Complete Schedule 7 (Aggregate Investment Income) and Schedule 23 if you are part of an associated group of corporations. The SBD is calculated automatically based on these schedules.
If your accountant is not claiming the SBD on your behalf and you are a CCPC, ask why. There is rarely a good reason to not claim it.
The SBD is the single most important reason to incorporate a Canadian business once you are profitable. The math becomes overwhelming somewhere around $80,000 to $120,000 of annual profit. Below that, the cost of incorporation often outweighs the benefit. Above it, you are leaving real money on the table by staying a sole proprietor.