For Business Owners — Guide
Your corporation's investments are taxed twice: once on their income, and again by quietly grinding away the small business rate. Here's the rule, the cost, and the four ways out.
What is the passive income grind?
Since 2019, a Canadian-controlled private corporation loses $5 of its $500,000 small business limit for every $1 of passive investment income above $50,000 a year. At $150,000 of investment income the limit is gone — and active profits are taxed at 26.5% instead of 12.2% in Ontario.
Here's how most owners meet this rule. You've run a profitable company for a decade. You didn't need all the profit personally, so it stayed inside — first as cash, then as GICs, then a portfolio. Nobody sent a warning letter. Then one spring your accountant mentions, almost in passing, that your corporate tax bill went up because "your investment income ground the SBD." That sentence costs some owners more than their mortgage does.
The measure is adjusted aggregate investment income (AAII) — broadly, your corporation's interest, rent, royalties, portfolio dividends and the taxable half of realized capital gains, aggregated across associated corporations. The test looks at last year's AAII to set this year's small business limit:
| Passive income (AAII) | Small business limit left | Extra Ontario corporate tax* |
|---|---|---|
| $50,000 or less | $500,000 (full) | $0 |
| $75,000 | $375,000 | $17,875/yr |
| $100,000 | $250,000 | $35,750/yr |
| $125,000 | $125,000 | $53,625/yr |
| $150,000+ | $0 | $71,500/yr |
*Assumes active profits of at least $500,000; ON combined rates 12.2% small business vs 26.5% general, 2025/26. Source: ITA s.125(5.1); Ontario 2025 corporate rates.
Two things make the grind sneakier than the table suggests. First, it's driven by income, not intent — a one-time realized gain on a rental property inside the corporation can wipe out next year's limit even if your "normal" yield is modest. Second, it compounds against you: retained earnings keep growing, so a portfolio that's safely under $50,000 of income today crosses the line on autopilot in a few years. Run your own numbers in LAB 01 — the crossing year surprises most owners.
The 2018 federal budget's target was the deferral advantage: money earned at 12.2% and invested corporately has roughly 40 cents more working capital per dollar than money taxed personally first. Ottawa didn't ban the deferral — it made large-scale corporate investing progressively more expensive. Owners occasionally hope this rule gets repealed; it has survived two governments, and Budget 2025 tightened the perimeter around it (limiting Part IV deferral through tiered corporations) rather than loosening it. Plan as if it's permanent.
Counts: interest, foreign dividends, portfolio (non-connected) dividends, net rental income, royalties, and the taxable half of realized capital gains.
Doesn't count: active business income; dividends from connected corporations (those face Part IV rules instead); capital gains on assets used in the active business; gains sheltered in a deferral you haven't triggered — unrealized appreciation only counts when you sell; and — the one that reshapes planning — growth inside an exempt life insurance policy. Cash value accumulating in a corporately-owned participating policy is not annual investment income, because the corporation doesn't receive it annually. It compounds inside the exempt policy and never touches the AAII test.
Salary or dividends move future investing outside the corporation. It works — at the price of the very tax you were deferring (up to 53.53% salary / 47.74% non-eligible dividends at the top). Sensible when personal registered room (RRSP/TFSA/IPP) is unfilled; expensive as a wholesale strategy.
Which investments sit where matters. Interest-heavy assets are the worst AAII offenders per dollar of return; deferred-growth equities barely register until sold. Some families move income-producing assets to a holding company structure to protect the operating company's QSBC status — note this moves the AAII problem, it doesn't remove it, since the grind aggregates across associated corporations.
Repositioning part of the portfolio into a corporately-owned participating whole life policy takes that capital out of the AAII test entirely, while it keeps compounding (tax-free inside the exemption) and adds a death benefit that later exits through the Capital Dividend Account. On $1.5M yielding 5%, that's the difference between $75,000 of AAII and $25,000 — between losing $17,875 every year and losing nothing. Owners who want the capital still deployable can layer an Immediate Financing Arrangement on top — with its own risks, covered honestly on that page.
If your corporation's investment horizon is short — a sale, a large purchase, retirement drawdown within a few years — restructuring costs can exceed the grind. Part of an honest diagnostic is telling you when the boring answer wins.
Fair warning
The insurance route only fits owners with stable surplus cash flow and a 5+ year horizon. If either is missing, fixes #1 and #2 — or doing nothing — will serve you better. We'll say so.
AAII is a CCPC's passive investment income for the small business deduction test: interest, portfolio dividends, rents, royalties and the taxable half of realized capital gains, aggregated across associated corporations. Active business income and exempt life insurance policy growth are not included.
Up to $50,000 of AAII per year has no effect. Above that, the $500,000 small business limit shrinks by $5 per $1 of passive income, disappearing entirely at $150,000.
No. Growth inside an exempt life insurance policy is not adjusted aggregate investment income, because the corporation doesn't receive it as annual investment income. This is why corporately-owned participating policies are a common response to the grind.
No — only the taxable half of realized gains counts, in the year of sale. That cuts both ways: deferring sales protects your limit, but a single large sale can grind away next year's limit all at once.
Book a Tax Diagnostic
The first conversation is free — your situation, our method, and whether we fit. Complex files quote a planning fee up front: you'll know before we start.
// the only variable in this plan that gets more expensive every year is your age