What Counts as Passive Income in a Corporation (and What Doesn't)?

Once your corporate portfolio is large enough that the $50,000 passive income rule is in play, the next question is precise: what exactly counts? The measure is called adjusted aggregate investment income, or AAII, and the definition has enough edges that reasonable people guess wrong about half of it. Interest counts. Unrealized gains don't. Dividends depend entirely on who pays them. And several things that feel like they should matter, like taking money out, change nothing.

Here is the checklist, followed by the edges worth knowing.

The checklist

Two reminders on how the number is used: the threshold is tested against the prior year's AAII (this year's investment income sets next year's business limit), and when corporations are associated, the grind runs on the group's combined AAII against one shared limit.

Interest, rent, and royalties: the always-counted core

Interest is the simplest and the harshest case: it counts in full, every year, with no timing control. A corporation holding $1.5 million in 4.5% GICs generates about $67,500 of AAII annually before anything else is added, which is already $17,500 past the threshold. This is why a "safe" corporate GIC ladder is often the very thing quietly shrinking a small business deduction.

Rent and royalties count too, with one exception that matters to professionals with real estate: rent received from an associated corporation that uses the property in its active business is recharacterized as active income. Rent from arm's-length tenants stays passive. The classification is done lease by lease, so mixed-use buildings need an accountant's eye.

Capital gains: realized only, and only half

Capital gains have two built-in discounts. Nothing counts until a gain is realized, and when it is, only the taxable half enters AAII. The inclusion rate is 50%: the proposed increase was cancelled in March 2025. A $60,000 realized gain therefore adds $30,000 to AAII, while the same $60,000 sitting unrealized adds zero, indefinitely.

That makes realization timing the single most controllable AAII input. Selling a large position in one year can blow through the threshold once; selling it across three years may keep every year under $50,000. The same logic applies to the untaxed half of each gain, which is credited to the capital dividend account for eventual tax-free extraction, a mechanic covered in the pillar guide.

One asymmetry to respect: current-year capital losses net against current-year gains and reduce AAII, but net capital losses carried forward from other years do not. The AAII definition adds those carryovers back, precisely so that old losses cannot be used to protect the small business limit.

Dividends: the 10% rule

Whether a dividend counts depends on the relationship between your corporation and the payer. Dividends from portfolio holdings, meaning corporations in which you hold less than 10%, count toward AAII, and that includes foreign dividends. Dividends between connected corporations, where your corporation holds a significant stake (broadly, more than 10% of votes and value), generally flow tax-free and stay out of AAII.

For an incorporated physician or dentist whose portfolio is mutual funds, ETFs, and individual stocks, the practical answer is blunt: effectively all of those distributions are portfolio dividends, and they count. The connected-corporation exclusion mostly matters to owners with genuine multi-company structures.

What never counts

Three exclusions do real planning work:

• Growth inside an exempt life insurance policy. Cash value growth in a corporately-owned permanent policy is tax-sheltered and produces no AAII at all. This is why insurance appears in nearly every serious grind-management conversation, and it is one of the strategies compared in the pillar guide.
• Unrealized gains. A growth-tilted portfolio with low distributions can compound for years while reporting very little AAII. Composition, not just size, sets your number.
• Registered assets. RRSPs and Individual Pension Plans are not corporate investment assets; income inside them never touches AAII. Moving corporate savings into an IPP shrinks the AAII engine directly.

If the goal is choosing among these levers rather than defining them, the comparison with numbers lives in the pillar guide's strategy section.

Two portfolios, same size, very different grind

Because the checklist weighs income types so differently, two corporations with identical $2 million portfolios can face completely different grinds. Compare a GIC-heavy portfolio with a growth-tilted one:

Portfolio A never sells anything and feels conservative, yet it costs $12,000 a year in extra tax on the corporation's active income (the ground-down income pays 17.2% instead of 11.2%, since Ontario does not parallel the federal grind), before counting the roughly 50% annual tax on the interest itself. Portfolio B reports less than half the AAII while (in most long runs) compounding faster, because most of its return accrues as unrealized gains that count for nothing until sold.

This is not an argument that every professional corporation should hold equities; risk tolerance and time horizon come first. It is an argument that the same risk decision can often be implemented in a more or less AAII-efficient wrapper, and the difference between wrappers is measured in thousands to tens of thousands of dollars a year once the portfolio is large, counting both the grind and the annual tax on the income itself.

Why taking money out doesn't help

This is the most common instinct and it does nothing: paying yourself a dividend or a salary does not reduce AAII, because AAII measures what the corporation earns on its investments, not what it holds or distributes. The portfolio that generated $80,000 of investment income has generated it, whether you then withdraw $200,000 or nothing.

Withdrawals do work indirectly, over time. Money paid out (into an RRSP, a TFSA, a mortgage paydown) is money no longer inside the corporation producing next year's AAII. But that is a slow lever measured in years, not a fix for the current test. What moves the number this year is changing what the remaining assets earn and when gains get realized.

How to find your number

The authoritative figure is on Schedule 7 of your T2 return, and the one that matters for planning is last year's, since prior-year AAII sets the current business limit. Two figures worth requesting from your accountant every year: prior-year AAII, and the projected figure for the current year while there is still time to act on it.

For a directional check before that conversation, the passive income and SBD calculator shows what any given level of investment income does to the business limit and the tax bill at 2026 Ontario rates. If your AAII is within $20,000 of the threshold in either direction, the composition questions above stop being trivia and start being money.

And if the composition questions raise more than the calculator can answer, the way I work through AAII planning with incorporated physicians is on the financial planning for physicians page.