Passive Investment Income in Your Corporation: How It Grinds Down Your Small Business Limit

Many Ontario business owners discover the appeal of leaving money inside their corporation: pay corporate tax at the low small-business rate, then invest the after-tax retained earnings in stocks, bonds, or rental properties — all sheltered inside the company. For years this was a popular strategy. Then the rules changed.

Today, passive investment income earned inside a Canadian-controlled private corporation (CCPC) triggers a mechanism that can reduce — or completely eliminate — your corporation's access to the small business deduction. This is commonly called the passive income grind or the small business limit grind. Understanding it is essential for any Ontario owner-manager with significant savings inside a corporation.

As always, the specific thresholds and rates involved are set by legislation and can change with each federal budget. Confirm current figures with a licensed accountant.

What Counts as Passive Investment Income?

Passive income, for purposes of these rules, includes income your corporation earns from investments rather than from actively running a business:

• Interest on bonds, GICs, savings accounts
• Taxable dividends received from non-connected corporations (e.g., publicly traded shares)
• Taxable capital gains (the portion included in income) from selling investments
• Rental income from a property that does not constitute an active business
• Royalties and similar passive receipts

Active business income — what the corporation earns from selling goods, providing services, or operating a genuine business — does not count toward the passive income threshold.

Note: dividends received from connected corporations (other Canadian private corporations with which you have a connection under the tax rules) are excluded from the calculation in most cases.

How the Grind Mechanism Works

The Income Tax Act provides a formula: for every dollar of adjusted aggregate investment income (AAII) that your CCPC and any associated corporations earn above a defined annual threshold (as of writing — confirm the current threshold with the CRA), the federal small business limit is reduced by a set multiple of that excess.

In practical terms, if your corporation earns passive income above the threshold, you lose access to more and more of the low small-business rate, dollar for dollar. If your passive income is high enough, the small business limit goes to zero entirely. At that point, all active business income is taxed at the higher general corporate rate.

The Ontario small business deduction is similarly reduced in line with the federal limit.

The Refundable Tax Mechanism: RDTOH

To prevent double taxation on passive income earned inside a corporation, a portion of the tax your corporation pays on that passive income is refundable. The mechanism involves a notional account called Refundable Dividend Tax on Hand (RDTOH). When the corporation pays taxable dividends, it gets a refund of a portion of the RDTOH balance.

The idea: the government taxes passive income at a high corporate rate, but refunds the excess when the money is eventually paid out as dividends, so that the total tax — corporate plus personal — is approximately equal to what a high-income individual would have paid on the income directly. It keeps the system "integrated."

There are two RDTOH pools — eligible RDTOH (linked to eligible portfolio dividends) and non-eligible RDTOH (linked to interest, capital gains, and other passive income). The refund is triggered by paying the corresponding type of dividend. The mechanics are detailed; your accountant manages the RDTOH balance annually.

Capital Dividend Account: The Tax-Free Slice

One genuinely valuable feature of the corporate investment structure is the Capital Dividend Account (CDA). When your corporation realizes a capital gain, only a portion of that gain is included in income (the taxable portion). The other portion — the non-taxable part of the capital gain — is added to the CDA.

Amounts in the CDA can be paid to shareholders as a capital dividend: a tax-free dividend at the personal level. The CDA is discussed in more detail in a separate article, but it is one reason why holding investments that generate capital gains inside a corporation can still be advantageous even after the passive income rule changes. The tax-free CDA distribution is a real benefit that survives the grind.

Planning Around the Grind

Option 1: Keep Passive Income Below the Threshold

If your CCPC earns modest passive income — below the annual threshold — the grind does not apply. Careful management of the investment portfolio (e.g., preferring growth assets with deferred capital gains over interest-paying instruments) can keep passive income low in any given year.

Option 2: Hold Investments Personally

For business owners whose corporation is already earning passive income near or above the threshold, it may make sense to stop accumulating more investments inside the corporation and instead take salary or dividends to fund personal investment accounts (RRSP, TFSA, or a non-registered account). The loss of the small business limit on active income can outweigh the corporate investment advantages.

Option 3: Segregate Investment Activities

Some advisors suggest holding passive investments in a separate holding company that is not associated with the operating company — but the rules catch associated corporations in the grind calculation, so this only works in limited circumstances. Get professional advice before attempting this.

Option 4: Life Insurance Products

Certain exempt life insurance policies held inside a corporation accumulate investment value without triggering AAII in the same way. This is a specialized planning tool that an insurance advisor and accountant should evaluate together.

Frequently asked questions