31 August 2026
Adjusted Aggregate Investment Income and Your Corporation’s Small Business Deduction
Adjusted aggregate investment income can take away the small business deduction even when the operating business is healthy. If a CCPC and its associated corporations earn more than $50,000 of that income in the prior year, the $500,000 federal business limit starts to shrink. At $150,000, the limit can fall to nil. This guide explains the grind, what counts as passive income, and how Vancouver owners plan around it. Thresholds below are the current federal rules as of August 2026.
Investment income inside the company has a second cost
Passive income in a corporation is already taxed at a high refundable rate. The grind is the extra cost: last year’s investment income can push this year’s active business income onto the higher general rate. For a BC CCPC, that is the difference between about 11% and about 27% on income that used to qualify for the small business deduction.
What is adjusted aggregate investment income?
For the small business deduction grind, CRA and the Income Tax Act use a defined amount called adjusted aggregate investment income, or AAII. In plain terms it is the group’s investment income for taxation years ending in the previous calendar year, with specific inclusions and exclusions. It generally includes interest, most taxable capital gains (net of current-year capital losses), portfolio dividends from non-connected corporations, rental income that is not active business income, and certain income from life insurance policies.
AAII generally excludes dividends from connected corporations and capital gains on assets used in an active business. Net capital-loss carryforwards from earlier years do not reduce AAII. That last point surprises owners who sell a portfolio and assume an old capital-loss pool will protect the business limit.
This is a different issue from the high tax rate on investment income itself. A CCPC still pays a high refundable tax on most passive income, with part refundable when it pays taxable dividends. The grind is about next year’s corporate tax rate on active income. Both can apply in the same year.
Who does the small business deduction grind apply to?
The reduction applies to a Canadian-controlled private corporation when the AAII of the corporation and the corporations associated with it, for taxation years ending in the preceding calendar year, exceeds $50,000. Associated corporations share one business limit. They also share the AAII that grinds that limit. A holding company with a large investment portfolio can therefore reduce the operating company’s small business deduction even if the operating company itself owns no GICs or rentals.
The grind is the greater of the passive-income reduction and the older taxable-capital reduction. Very large CCPCs can lose the SBD because of taxable capital even if AAII is low. Most Vancouver owner-managed groups hit the passive-income rule first.
How the $50,000 / $150,000 formula works
Subsection 125(5.1) reduces the business limit by five dollars for every dollar of associated-group AAII above $50,000. The federal business limit is $500,000, so $100,000 of excess AAII wipes it out. That excess is $150,000 minus $50,000.
| Prior-year group AAII | Limit remaining | Active income still at the SBD rate |
|---|---|---|
| $50,000 or less | $500,000 | Full limit, if no other reduction applies |
| $70,000 | $400,000 | $20,000 excess × 5 = $100,000 reduction |
| $100,000 | $250,000 | Half the federal limit is gone |
| $125,000 | $125,000 | $75,000 excess × 5 = $375,000 reduction |
| $150,000 or more | $0 | All qualifying active income is at the general rate |
The reduction uses AAII of the corporation and associated corporations for taxation years that ended in the preceding calendar year. Confirm associated-status and the exact AAII computation on Schedule 7 and the T2 for your year.
A British Columbia example with numbers
A Vancouver operating company earns $400,000 of active business income. Its associated holding company earned $90,000 of AAII last year from interest, portfolio dividends, and a capital gain on publicly traded shares. Excess AAII is $40,000. The federal business limit falls by $200,000, to $300,000.
| Scenario | Income at ~11% | Income at ~27% | Estimated corporate tax |
|---|---|---|---|
| Full $500,000 limit available | $400,000 | $0 | ~$44,000 |
| Limit ground to $300,000 | $300,000 | $100,000 | ~$60,000 |
| Limit ground to $0 | $0 | $400,000 | ~$108,000 |
The middle row costs about $16,000 more than the full-limit row, using the same rounded BC rates as our corporate-tax-rate guide (about 11% small business and 27% general, current as planning figures for 2026). The holding company’s portfolio also paid high refundable tax in the year it earned the $90,000. Owners often notice the investment tax first and miss the grind until the next T2.
What counts, and what does not
Usually in AAII
Interest, most portfolio dividends, taxable capital gains on investments, and rental income that is not an active business.
Usually out of AAII
Dividends from connected corporations and gains on assets used principally in an active business.
Associated groups share it
You cannot hide the grind by parking investments in a Holdco if the companies are associated. The group AAII is what matters.
Last year drives this year
A large gain in 2025 can grind the 2026 business limit even if you sell the portfolio and hold cash this year.
Planning options, without inventing loopholes
There is no election that turns investment income off. Owners who want to keep the small business rate usually change what sits inside the associated group, or when income is realized:
Measure group AAII early
Estimate interest, rents, portfolio dividends, and planned capital gains before year-end, including every associated company.
Watch one-time gains
A single securities sale can push AAII over $50,000 or $150,000. Timing and the active-business-asset exclusion need a file-specific review.
Review the structure
A holding company still has asset-protection and estate uses. It does not automatically shelter the operating company from the grind if the companies are associated.
Plan compensation and refundable tax
Paying taxable dividends can recover refundable tax on hand. That is separate from restoring the business limit. Coordinate both with salary versus dividends.
Common mistakes
Looking only at the operating company
Associated Holdco interest and capital gains count. The T2 association schedule is part of the SBD calculation, not optional extra paper.
Treating rental as always passive
Some rental operations are active businesses. Most small portfolios are not. The classification changes both the tax rate and AAII.
Using old capital losses to “fix” AAII
Current-year capital losses can offset current-year gains in the AAII computation. Loss carryforwards from earlier years generally do not.
Forgetting the grind lasts a year
Cleaning up the portfolio this year protects next year’s limit. This year’s SBD is already set by last year’s AAII.
When professional CPA advice becomes useful
Get advice when the group has a Holdco with investments, you expect a large capital gain, taxable capital is also rising, or the operating company is approaching $500,000 of active income. The file needs an association analysis, an AAII estimate, and a comparison of SBD tax against refundable tax and personal tax on extraction. That is standard corporate tax planning and should show up correctly on the T2.
Frequently asked questions
Is investment income reducing your small business deduction?
J. Wang Chartered Professional Accountant calculates group adjusted aggregate investment income, the remaining business limit, and whether investment income inside the company is costing more than it should.
