A professional corporation (PC) can be a powerful tax-planning vehicle for a doctor, dentist, or lawyer — but it behaves very differently from a typical operating company. The rules that make incorporation attractive (the small-business deduction, tax deferral, income splitting) are the same rules that have been steadily narrowed over the past several years. Strategies built for a manufacturer or retailer often do not translate cleanly to a service practice.

This article walks through the core decisions an incorporated professional faces — how to pay yourself, how the passive-investment-income rules affect retained earnings, when income splitting is available, whether the Lifetime Capital Gains Exemption is realistically within reach, how an individual pension plan can boost retirement saving, and how to approach holding companies and exit. The figures reflect the rules as they stand in 2026, but tax law changes often, so treat thresholds as a starting point.

First, what a professional corporation can and cannot do

Every regulated profession that permits incorporation does so through its governing body, and the rules on who can own shares vary significantly by province and by profession. This matters enormously, because the most valuable planning levers — splitting income with a spouse, layering in a holding company — depend entirely on who is allowed to hold which shares.

For physicians and dentists in Ontario, the Business Corporations Act permits certain family members (defined as a spouse, child, or parent) to hold non-voting shares of a medicine or dentistry professional corporation, while voting shares must remain with members of the profession. However, the College of Physicians and Surgeons of Ontario does not currently permit a holding company to own shares of a medicine professional corporation, which closes off some structures available to ordinary businesses.

For lawyers, the Law Society of Ontario is more restrictive. All issued shares of a legal professional corporation — voting and non-voting alike — must be legally and beneficially owned, directly or indirectly, by licensees of the Law Society. In practice this means the family-share income-splitting strategies that medical and dental PCs sometimes use are generally not available to a law PC, and any holding company in the structure must itself be owned only by licensees.

Other provinces draw these lines differently, and the rules can change. Before you build any structure, confirm the current share-ownership and holding-company rules with your regulator. Getting this wrong is not merely a tax problem — it can put your licence to practise at risk.

Salary versus dividends: the annual decision

Because a PC is a separate taxpayer, you choose how to extract money from it. The two main routes are salary (deductible to the corporation, taxed as employment income to you) and dividends (paid from after-tax corporate profits, taxed at lower personal rates with a dividend tax credit). Thanks to integration, the combined corporate-and-personal tax on a dollar earned and paid out is roughly similar either way at most income levels — so the decision usually turns on factors other than the headline rate.

The considerations that tend to drive the choice in 2026 are:

RRSP room. Only salary creates RRSP contribution room; dividends do not. The 2026 RRSP dollar limit is $33,810, and because room is calculated as 18% of the prior year's earned income, you generally need roughly $187,800 of prior-year salary to generate the maximum. If you want to fully fund an RRSP, you need to pay yourself salary.
CPP. Salary requires both the employee and employer halves of CPP contributions, which on eligible earnings up to the 2026 Year's Maximum Pensionable Earnings of $74,600 is a meaningful cost. Some professionals view CPP as a worthwhile inflation-indexed annuity; others prefer dividends to opt out.
Borrowing capacity. Lenders generally find a steady T4 salary easier to underwrite than dividend income on a mortgage or practice-acquisition loan.
Cash flow and deferral. Leaving profit in the corporation at the corporate rate, deferring personal tax to a later year, is one of the main reasons to incorporate.

For most incorporated professionals the practical answer is a blend, set each year against personal cash needs, RRSP goals, and how much profit can stay in the company. This is a calculation worth redoing annually rather than locking in once.

The small-business deduction and the passive-income grind

The reason deferral works at all is the small-business deduction (SBD), which taxes the first $500,000 of active business income in a Canadian-controlled private corporation at a low combined rate instead of the general corporate rate. That gap between the low rate and your personal rate is the deferral advantage — money you can reinvest or hold rather than pay out and tax immediately.

The catch for professionals who retain earnings is the passive-investment-income rule that has applied since 2019. Once a corporation's adjusted aggregate investment income (AAII) — broadly, the income its investment portfolio throws off — exceeds $50,000 in a year, the $500,000 business limit is ground down by $5 for every $1 of AAII over the threshold. By the time AAII reaches $150,000, the business limit is reduced to zero and the corporation pays the general rate on all of its active income.

This is precisely the trap a successful practice can walk into. You defer tax by leaving profits in the PC, you invest those retained earnings, the portfolio grows, and eventually the income it generates erodes the very low-rate room that made deferral worthwhile. If you own more than one corporation and they are associated, the $50,000 threshold and the $500,000 limit are shared across the group, so you cannot sidestep the rule by spreading investments around.

Managing the grind is an active exercise. Options include shifting corporate investments toward growth assets that defer realized income, using corporately owned permanent life insurance whose growth is not AAII, or paying out dividends to keep the portfolio from compounding. Each has trade-offs, and the right mix depends on how close you are to the threshold and what you are saving for.

Income splitting and the TOSI limits

Historically, a major attraction of a PC was sprinkling dividends to lower-income family members. The tax on split income (TOSI) rules, in force since 2018, have largely closed this door for service professionals — and understanding why is essential before you assume splitting is available.

TOSI applies the top marginal rate to "split income" received by a family member unless an exception applies. Two exceptions matter most here:

The excluded business exception, where a family member aged 18 or older is actively and regularly engaged in the business — a common benchmark being an average of at least 20 hours per week. A spouse who genuinely works in the practice may qualify; a spouse who does not generally will not.
The excluded shares exception, which can shelter dividends for an owner aged 25 or older who directly holds at least 10% of the votes and value of the corporation. Crucially, this exception is unavailable where 90% or more of the corporation's business income comes from providing services. A medical, dental, or legal practice is almost by definition a service business, so the excluded-shares route is generally closed to professional corporations.

The combined effect is that paying dividends to a non-working spouse or adult child simply because they hold shares will usually attract TOSI at the top rate, eliminating the benefit. Genuine, documented involvement in the practice is the most reliable path to splitting income. Splitting through a salary for actual work performed (at a reasonable rate for that work) sits outside TOSI entirely and is often the cleaner option.

The Lifetime Capital Gains Exemption — and why it is hard for a PC

The Lifetime Capital Gains Exemption (LCGE) can shelter a capital gain on the sale of qualified small business corporation (QSBC) shares. For 2026 the exemption is $1,275,000 and is now indexed to inflation, so it rises modestly each year.

In practice, several hurdles stand between an incorporated professional and the LCGE:

Qualifying as a QSBC. The shares must meet asset tests — broadly, that at the time of sale at least 90% of the corporation's assets by value are used in an active business carried on primarily in Canada, and that more than 50% were so used throughout the prior 24 months. A practice that has invested years of retained earnings can easily fail the 90% test because of accumulated cash and investments. Purification — moving passive assets out before a sale, often to a connected company on a tax-deferred basis — is frequently required and takes planning well ahead of any transaction.
Whether the practice is sold as shares at all. Many practices are sold as an asset sale (the buyer takes the patient or client list, equipment, and goodwill) rather than a share sale, particularly where the regulator restricts who may own the PC's shares. The LCGE applies to a share sale, so an asset sale does not directly access it.
Regulatory limits on buyers. Because only members of the profession (and sometimes limited family members) can hold PC shares, the pool of potential share buyers is narrower than for an ordinary business.

None of this means the LCGE is unavailable — for a practice sold to another professional on a share basis after careful purification it can be valuable, and multiplying the exemption across qualifying family shareholders may be possible where the regulator permits family ownership. But it is rarely automatic, and it requires the structure to be set up with the eventual sale in mind years earlier. You can read more on our Lifetime Capital Gains Exemption page.

Individual pension plans for higher-income professionals

An individual pension plan (IPP) is a defined-benefit pension plan your corporation sponsors for you. For an established professional with consistent high T4 income, an IPP can permit larger tax-deductible retirement contributions than an RRSP, with room growing as you age rather than capped at the flat RRSP dollar limit. Because the corporation contributes, those amounts reduce corporate taxable income, and a one-time deductible "past service" contribution for earlier employment years is sometimes available.

The trade-offs are real: an IPP carries actuarial and administrative costs, the funds are locked in for retirement, and it only helps if you pay yourself a substantial salary (it does nothing on dividends alone, since it is tied to T4 earnings). As a rough guide, IPPs tend to become attractive for professionals over 40 with high, stable salaries, but whether one fits depends on your age, salary level, and other retirement assets.

Holding companies and the road to exit

A holding company sitting above an operating corporation can offer creditor protection for accumulated wealth, a way to manage when income is realized personally, and estate-planning flexibility. For incorporated professionals, the threshold question is again regulatory: as noted, a holdco generally cannot hold shares of an Ontario medicine PC at all, and any holdco in a law PC structure must be owned solely by licensees. Where a holdco is permitted, it is often used to hold investments separate from the practice — which can also help on the QSBC purification front. Our holding company tax strategy page explores these structures in more detail.

As you approach retirement or exit, planning shifts toward winding the practice down tax-efficiently: succession and post-mortem planning, paying out accumulated surplus over several years to smooth personal tax, capital dividend account balances payable tax-free, and the choice between an asset sale and a share sale. Because some of these moves take years to set up, effective exit planning starts long before you intend to stop practising.

A planning framework

For an incorporated professional, a sensible sequence looks like this:

Confirm the regulatory boundaries first. Establish what your governing body allows in terms of share ownership and holding companies before designing anything. The tax plan must fit inside the regulatory rules, not the other way around.
Set your annual compensation mix. Decide each year on salary versus dividends based on RRSP goals, CPP preference, cash needs, and how much profit can stay in the corporation.
Watch the passive-income threshold. Monitor AAII against the $50,000 line so the SBD grind does not quietly erase your deferral advantage.
Be realistic about income splitting. Assume TOSI applies unless a family member genuinely works in the practice or another exception is clearly met, and document the work that supports any splitting.
Fund retirement deliberately. Compare RRSP, corporate investing, and — for higher salaries — an IPP, rather than defaulting to one approach.
Plan the exit years ahead. If the LCGE is a goal, start purifying and structuring early, and decide whether a share sale is even realistic for your profession.

These decisions interact: retaining earnings to defer tax can jeopardize QSBC status later. That is why useful planning treats the PC as a single system reviewed regularly, not a set of one-time choices. You can learn more on our tax planning for incorporated professionals page, or explore related strategies across our tax services.

This article is general information, not legal or tax advice. The rules, thresholds, and dollar figures described here can change, and outcomes depend on your specific facts, your province, and your professional regulator. Speak with a qualified tax lawyer or advisor before acting.

Tax Planning for Incorporated Professionals: Doctors, Dentists, and Lawyers