The $50,000 passive income rule and your small business limit

If your corporation has been accumulating for a decade, this is the rule that quietly starts charging you for it. Most physicians meet it for the first time in a letter from their accountant, a year after it began.

What the rule actually says

A Canadian-controlled private corporation gets a small business limit of $500,000 of active business income taxed at the reduced rate. That limit is reduced when the corporation, together with any associated corporations, earns adjusted aggregate investment income between $50,000 and $150,000 in the previous tax year.

The reduction is $5 of business limit for every $1 of adjusted aggregate investment income above $50,000. At $150,000 of investment income the business limit is nil (Canada Revenue Agency).

There is a second, older reduction based on taxable capital employed in Canada, which starts at $10 million. Very few professional corporations reach it. The passive income grind is the one that bites.

What does the grind cost?

Active business income that no longer fits under the small business limit is taxed at the general combined Ontario rate of 26.5 per cent instead of the small business rate, which blends to 11.7 per cent for a 2026 calendar year end (Canada Revenue Agency; Ontario Ministry of Finance).

Now the part most articles skip. That extra corporate tax is not all lost. Income taxed at the general rate goes into the corporation's general rate income pool and can be paid out as eligible dividends, which are taxed more lightly in your hands than the non-eligible dividends that small business income produces. The permanent cost is therefore smaller than the headline figure. What you genuinely lose is the deferral, and the deferral is the reason you incorporated.

How passive income is taxed inside the corporation anyway

Investment income earned in a professional corporation is taxed at roughly 50 per cent in Ontario when it is earned, which is close to your top personal rate. A large refundable portion is tracked in refundable dividend tax on hand and returned to the corporation when it pays taxable dividends, at a rate of $38.33 for every $100 of dividends paid (Canada Revenue Agency).

So the corporation is not a tax shelter for investment income. It is a deferral on active income, with investment income taxed at a personal-like rate while it sits there and a refund mechanism when it comes out.

How do I know whether I am close?

The threshold is about income, not about the size of the account, so the answer depends on what the portfolio holds.

At a 4 per cent taxable yield, $50,000 of adjusted aggregate investment income corresponds to roughly $1.25 million of corporate investments. At a 2 per cent yield it takes $2.5 million. A portfolio of guaranteed investment certificates crosses the line at a much smaller balance than a portfolio of broad equity funds held for growth, because interest is fully included the year it is credited and unrealised growth is not included at all.

The figure you need is on schedule 7 of your T2 return, and your accountant already calculates it each year. Ask for the number rather than estimating it. Associated corporations are added together, so if you and your spouse each hold a professional corporation and they are associated, one $500,000 limit is shared between them and both portfolios count.

What you can actually do

Pay more out. Increasing salary or dividends moves money from the corporation to registered and personal accounts, where the grind does not apply. Salary also creates RRSP room. Check the effect in the salary vs. dividends calculator.

Fill the registered accounts first. TFSA, RRSP, FHSA where you qualify, and RESP contributions all sit outside the corporation and outside adjusted aggregate investment income.

Change what the portfolio holds, not just how much. A corporate portfolio weighted towards broad equity growth and Canadian dividends generates less adjusted aggregate investment income per dollar invested than one weighted to interest. This is a real trade-off: you are choosing an asset mix partly for tax reasons, and that should not override your risk tolerance or your time horizon.

Consider a pension. An individual pension plan, or HOOPP for incorporated physicians drawing salary, moves retirement assets out of the corporation entirely.

One thing to be clear about: none of these responses makes the grind disappear while a large corporate portfolio keeps producing income. They shift when and where the income is reported. A corporation holding $3 million of interest-bearing investments will grind the limit to nil in most years, and the honest conclusion is that the corporation stopped being the right home for that money some time ago.

And run the timing. The grind uses the previous year's investment income, so a large realised gain this year affects next year's small business limit. If you are rebalancing a corporate portfolio, knowing that in November is worth more than knowing it in April.

AAII

Adjusted aggregate investment income. The measure of passive income that triggers the grind, broadly interest, rents, foreign dividends and taxable capital gains.

Small business limit

The $500,000 of active business income eligible for the reduced corporate rate, before any reduction.

General rate

The combined Ontario corporate rate of 26.5 per cent that applies to active business income above the small business limit.

RDTOH

Refundable dividend tax on hand. The pool of corporate tax on investment income that is refunded when the corporation pays taxable dividends.

GRIP

General rate income pool. The balance that lets a corporation pay eligible dividends, which are taxed more lightly in your hands.

What to bring to a 20-minute review

Bring your last two T2 returns, a current statement for every corporate investment account, and your realised gains for the year to date. We will work out where you sit against the $50,000 threshold, what next year's business limit looks like, and whether the fix is a payout, a portfolio change or a pension.

Book a 20-minute review