The order matters more than the products
Answer first: hold back genuine working capital, direct enough salary to fill your RRSP and TFSA, then invest what remains inside the corporation, and revisit the split every year. Most incorporated professionals do this backwards. Surplus piles up in the corporate account, a portfolio gets opened inside the corporation by default, and only later does anyone ask whether some of those dollars had a better home. By then the money is locked behind a personal tax bill on the way out.
The order exists because each destination is taxed differently, and the differences compound for decades. A dollar left in the corporation was taxed at 12.2 percent if your practice income sits within the Ontario small business limit, so more of it goes to work immediately; that is the real advantage of incorporation. But once that dollar starts earning interest or dividends inside the corporation, the earnings are taxed at roughly fifty percent as they arise, while the same earnings inside an RRSP or TFSA would grow untouched.
So the honest framing is a race between a bigger starting amount growing in a taxed account and a smaller starting amount growing in a sheltered one. Neither wins universally. The sequencing above wins on average because it captures the corporate deferral and the personal shelters instead of choosing one, and it is the default we set for physicians, dentists and therapists in our dentist tax planning work before any product discussion happens.
Why corporate investing is still worth doing, honestly stated
The corporation earns its place in the plan through deferral, not through a low rate on investment returns. Keeping profit inside the corporation instead of drawing it means personal tax is postponed, sometimes for decades, and the postponed tax stays invested in the meantime. For a professional earning well above their spending, that deferred layer becomes the largest pool of capital they will ever control, which is why the corporate portfolio usually ends up bigger than the registered accounts even when it is filled last.
The offset is how the earnings on that pool are taxed. Interest, foreign income and portfolio dividends inside a Canadian-controlled private corporation are taxed at roughly half as they arise, with part of that tax sitting in a refundable pool that comes back only when the corporation pays you taxable dividends. Capital gains do better: only half the gain is taxable, and the untaxed half lands in the capital dividend account, which can move to you tax-free. The system is built so corporate and personal investing land in a similar place once everything is paid out; the win is the timing, not the rate.
Two practical consequences follow. First, asset location matters: growth assets that produce capital gains suit the corporation better than interest-heavy holdings, a conversation for your advisor once the structure is set. Second, the refundable-tax plumbing only works if your dividend plan and your portfolio plan are coordinated, which is exactly the kind of ongoing decision our Ongoing Financial Partnership exists to keep on schedule rather than discover at year-end.
The grind: your portfolio can raise your practice’s tax rate
Past a threshold, investment income inside the corporate group starts taking away the small business rate on your practice income, and this is the constraint that should size the corporate portfolio. The measure is adjusted aggregate investment income: broadly interest, portfolio dividends, rents and the taxable half of capital gains, counted across your corporation and any associated corporations.
| Investment income in the group, per year | What happens to your small business limit |
|---|---|
| Under 50,000 dollars | Nothing. The full 500,000-dollar limit stands and practice profits keep the 12.2 percent combined Ontario rate. |
| 50,000 to 150,000 dollars | The limit shrinks by five dollars for every dollar over the threshold. At 100,000 dollars of investment income, half the limit is gone. |
| 150,000 dollars and above | The limit is gone entirely. Every dollar of practice profit is taxed at the general corporate rate. |
| What does not count | Gains on assets used in the active practice, and income already sheltered in registered plans or exempt insurance policies, sit outside the measure. |
Feel the scale of that. A portfolio in the low millions producing ordinary yield can cross the threshold on its own, and every dollar of limit lost moves practice profit from the small business rate to the general rate. The grind does not make corporate investing wrong; it makes portfolio size and composition a tax decision, not just an investment one. Capital-gains-oriented holdings, realization timing and, for some professionals, corporately owned exempt life insurance are the standard pressure valves, each with trade-offs worth a real conversation.
Compensation sets your options: salary, dividends and the accounts each one opens
How you pay yourself decides which shelters you are allowed to fill, so compensation and investing are one decision, not two. Salary creates RRSP contribution room and counts as earned income; dividends create no room at all. A professional who has paid themselves dividends only for a decade often discovers they have built no RRSP room and no eligibility for an individual pension plan, and that discovery usually arrives at exactly the age those vehicles matter most.
Our default for most incorporated professionals is enough salary to generate full RRSP room, with dividends layered on top to fund lifestyle and manage the refundable tax pools. Past the late forties, an individual pension plan becomes worth pricing for professionals with T4 history and steady practice income, because it allows larger deductible contributions than an RRSP and moves investment growth out of the corporation, away from the grind. It brings actuarial costs and less flexibility, so it is a fit question, not a default.
One caution on family. Dividends to a spouse or adult child who holds shares are usually caught by the tax on split income rules and taxed at the top rate unless a specific exception applies, and the exceptions are narrower for professional corporations than owners expect. Family compensation planning still has room to work, but it runs through actual work performed and careful share design, not through casual dividend sprinkling.
Structure: what the professional corporation rules allow, and what they block
For regulated health professionals in Ontario, the shareholder rules usually mean the portfolio lives inside the professional corporation itself, because the standard holding-company structure is off the table. Shares of a health-profession PC must be held by members of the profession, with a carve-out that lets family members of physicians and dentists hold non-voting shares directly. A holding company cannot own shares of the PC, so surplus cannot be dividended up to a separate investment company the way an ordinary operating business would do it. The full ownership map is in our professional corporations in Ontario guide.
Investing inside the PC works, but it stacks every egg in the entity that also carries your practice, so the design has to compensate. College rules generally require the corporation’s business to stay within the practice of the profession plus related or ancillary activities, and passively investing surplus is accepted practice territory, but a PC that starts to look like an investment company with a licence attached invites questions. Professionals whose college rules are more permissive, and non-health professionals such as consultants, have more room for multi-entity structures, which changes this answer materially.
The multi-entity considerations that remain for health professionals are narrower but real: a spouse’s corporation or a family trust operating outside the PC for non-professional activities, direct family share ownership where the profession allows it, and lending between entities done on documented terms. Every one of these has tax rules attached, so they get designed deliberately as Strategic Projects, not assembled from forum advice.
Keep the portfolio out of the practice’s way: reporting, financing, the exit
A portfolio inside the corporation changes how your financial statements read, and two audiences care: your lender and, for some professions, your eventual buyer. Banks financing a clinic build-out or an equipment purchase want to see the practice’s operations cleanly, and a statement where investment gains and practice income blur together makes underwriting slower and covenants clumsier. We keep clinic reporting separated from portfolio activity so the practice’s real margins stay visible, which is a quiet but constant part of how we support financing applications.
The exit matters for professionals whose practices actually sell, dentists and veterinarians most of all. A corporation heavy with passive investments can fail the tests that make the lifetime capital gains exemption available on a share sale, and cleaning that up in the year of sale is expensive and sometimes impossible. If a sale is plausible within your horizon, the portfolio’s size inside the practice corporation becomes an exit-planning constraint, and periodic purification belongs on the calendar.
What changes the answer, for any incorporated professional deciding where the surplus goes:
- The gap between what you earn and what you spend, because deferral only exists on dollars you truly do not need personally.
- Your profession’s corporation rules, which decide whether a holdco or family shareholders are even available.
- Your age and horizon, which set the value of RRSP room, pension options and deferral itself.
- Portfolio size against the passive-income threshold, which decides whether the grind is a future issue or a current cost.
- Whether the practice will ever be sold, which turns the portfolio into an exemption problem.
- Debt in the picture, because paying down practice or personal debt is a guaranteed return competing with everything above.
As a CPA firm for incorporated healthcare professionals in Ontario, we run this annually as part of the practice’s regular rhythm: set the salary-dividend mix, size the corporate portfolio against the grind, coordinate with your investment advisor, and keep the statements lender-ready. If you are still deciding whether incorporation is worth it at all, start with should a psychologist incorporate in Ontario, because retained earnings strategy only matters once there are retained earnings to strategize.
