How to Choose a CPA for a Medical Practice in Ontario (2026)
Reviewed by Bader A. Chowdry, CPA, CA, LPA on
Quick answer (55 words)
To learn how to choose a CPA for medical practice Ontario 2026, filter for eight criteria: MPC and CPSO Certificate of Authorization familiarity, OHIP/HRP reconciliation depth, physician-incorporation experience, TOSI defence for medical corporations, passive-income planning under s.125(5.1), locum vs. employee tax fluency, T4A/T4 knowledge, and a written engagement letter. Interview three CPAs before signing.
Last updated: July 19, 2026. Author and reviewer: Bader A. Chowdry, CPA, CA, LPA — Founder, Insight Accounting CPA Professional Corporation, Mississauga, Ontario.
Why “who is the best physician CPA” is the wrong first question
Most physicians start CPA-shopping the wrong way. They ask a colleague at the hospital, “who does your books?” and hire that person. Or they Google “top medical accountant Mississauga 2026” and pick a firm from the first page. Neither approach tests whether the CPA actually knows what a Medical Professional Corporation is, how OHIP payments reconcile against a general ledger, or why a professional corporation practising medicine cannot use the excluded-shares TOSI exception.
The better question is: what does my medical practice actually require of a CPA, and what does a CPA who does that work well look like? A salaried hospitalist with locum shifts has a completely different tax picture than a fee-for-service family physician in an incorporated group practice, and neither looks like a solo surgical specialist running an MPC with a family holdco on top.
Learning how to choose a CPA for medical practice Ontario 2026 starts with a criteria-based filter — the same filter this guide teaches. This is not marketing copy; it is a working buyer’s guide on how to choose a CPA for medical practice Ontario 2026 that you can use on any firm you shortlist. Insight Accounting CPA is used throughout as one worked example of a firm that meets these criteria — not as the only option. You pick the firm that fits, and you validate any CPA (including us) against the criteria below.
Compliance note. This guide follows CPA Ontario’s Code of Professional Conduct, including Rule 401 (practice names) and Rule 217 (advertising and solicitation). We do not identify, compare, or rank named competitor firms. We teach the physician-CPA selection criteria and let you evaluate any CPA against them.
The eight criteria: how to choose a CPA for medical practice Ontario 2026
1. MPC and CPSO Certificate of Authorization familiarity
A Medical Professional Corporation in Ontario is not an ordinary Ontario Business Corporations Act company. It is governed by the Medicine Act, 1991 and Ontario Regulation 665/05, which restricts voting-share ownership to members of the College of Physicians and Surgeons of Ontario and limits non-voting shares to specified family members (spouse, child, parent) and family trusts that meet the regulation’s conditions. Every MPC must hold a Certificate of Authorization issued by CPSO — application fee approximately $400, annual renewal $175 in 2026 — and must file an annual renewal on time to remain in good standing (CPSO — Incorporation Issuance and Renewal).
Test the CPA: ask them to describe the difference between voting and non-voting share ownership under Regulation 665/05 and who is eligible to hold each class. If they cannot answer without notes, they have not incorporated a physician in the last twelve months.
2. Physician incorporation experience — beyond the setup form
Setting up the numbered corporation, applying for the CoA, filing Articles of Amendment for the required share classes, and preparing the initial minute book is the easy part. The hard part is the design decisions that follow:
- Share-class architecture: how many classes, what discretionary dividend rights, what redemption features, whether non-voting shares are issued to a spouse directly or to a family trust.
- Salary vs. dividend mix in the first year and beyond, indexed to the physician’s OMA pension contributions and CPP position.
- Retained-earnings deployment: whether to build an in-corporation investment portfolio, how to structure the passive-income runway, and when to layer in a family holdco.
- Buy-sell mechanics if the MPC is a shareholder in a group-practice holdco or clinic operating company.
Ask any prospective CPA how many MPCs they set up in the last 12 months and how many they took from setup through year-three optimization.
3. OHIP and Health Reconciliation Payment reconciliation
Fee-for-service physicians receive weekly Ontario Health Insurance Plan (OHIP) payments and periodic Reconciliation Payments (rejects, holdbacks, retroactive adjustments). A CPA who has never mapped an OHIP remittance advice against a general-ledger revenue account will produce financial statements that look right at the top line and misstate accrued revenue, holdbacks, and cash timing.
Test the CPA: ask how they handle the timing gap between an OHIP fee code being submitted, adjudicated, paid, and later reconciled — and where the reconciling entries land in your monthly close.
4. TOSI defence for medical corporations — the professional-corp carve-out
The tax on split income (TOSI) rules restrict dividend income splitting with adult family members unless a specific exception applies. Physicians face a specific problem: the excluded-shares exception under s.120.4(1) of the Income Tax Act is not available to shares of a professional corporation that carries on the professional practice of medicine — this is explicitly stated in the CRA guidance (CRA — Tax on split income: Excluded shares).
A CPA who tells a physician they can “just pay a dividend to your spouse because the shares are excluded” is wrong for medical corporations. The available TOSI defences for MPC dividends to a spouse or adult children are:
- Excluded business — the family member is actively engaged on a regular, continuous, and substantial basis (generally 20 hours/week average) in the practice or a related business.
- Reasonable return — dividends measured against the family member’s labour, capital, risk, and historical contributions.
- Age-65 pension-splitting — once the physician-shareholder turns 65, dividends paid to a spouse from the MPC are excluded from TOSI regardless of the spouse’s contribution.
- Retirement transition of shares — pre-planned share redemptions or gifts around retirement age.
See the CRA’s general guidance at CRA — Guidance on the application of the split income rules for adults.
Test the CPA: ask them why the excluded-shares exception does not apply to an MPC. If they hesitate, they will get your dividend policy wrong.
5. Passive-income planning under s.125(5.1)
An MPC that retains after-tax earnings and invests them inside the corporation triggers the passive-income small-business-deduction (SBD) grind under subsection 125(5.1) of the Income Tax Act. The mechanic: for every $1 of adjusted aggregate investment income (AAII) above $50,000 in the prior year, the $500,000 SBD is reduced by $5. Full elimination at $150,000 of AAII. When the SBD is ground down, active business income is taxed at the general corporate rate rather than the small-business rate — a meaningful multi-year drag.
A physician-fluent CPA models the trade-off:
- Keep passive investments inside the MPC (defer personal tax, accept SBD grind) vs.
- Distribute active earnings as salary/dividend and invest personally (no grind, higher current personal tax) vs.
- Use a family holdco with individual pension plan (IPP) contributions to shelter active earnings from the passive pool.
6. Locum tax expertise: T4A vs. T4, GST/HST, and business-use-of-home
Locum physicians are almost always independent contractors, not employees. They receive T4A slips (or in some hospital-run programs, T4 slips), file GST/HST on non-exempt work, and can deduct a wider range of expenses than a salaried physician. But the CRA employee-vs-contractor test remains fact-based, and a locum working exclusively at one clinic can be reclassified as an employee — cancelling the deductions and triggering payroll assessments.
A CPA who does not routinely file locum returns will miss:
- Home-office deduction properly bracketed for licence-exempt vs. taxable revenue.
- CCA classification on medical instruments, computer equipment, and vehicle claims.
- CPP contributions on self-employment earnings (locum physicians pay both the employee and employer halves).
- RRSP room preservation and IPP eligibility once income supports it.
See the worked example: Case study — locum physician saves $24K via mid-year incorporation and spousal income split.
7. CDCP and program-payment awareness
The Canadian Dental Care Plan (CDCP) and expanding federal-provincial health programs are changing the payment mix for allied and adjacent practices — and, for family physicians who share administrative infrastructure with dental or vision practices, they change the HST allocation, cost-share arrangements, and revenue-recognition timing. A CPA who tracks federal-provincial health program rollouts will flag exposure and opportunities before the payer does.
8. Income splitting through a family holdco — done properly
For physicians with meaningful retained earnings, layering a family holdco above the MPC is a common structure. Done right, it enables:
- Creditor protection for post-tax earnings distributed as inter-corporate dividends.
- A vehicle for prescribed-rate spousal loans at the CRA prescribed rate (3% in Q3 2026; check the current quarter at CRA — Prescribed interest rates Q3 2026).
- A cleaner path to eventual capital-gains-exemption planning if the MPC and holdco meet the qualified small business corporation share tests — the 2026 lifetime capital gains exemption is $1,275,000.
Done wrong, it triggers TOSI, blows the excluded-shares question wide open again, and creates a Part IV tax exposure on inter-corporate dividends. Ask any CPA to walk through the reasoning behind their recommended holdco structure — a firm that recommends the same structure to every physician is a firm to walk away from.
What to ask any CPA who wants your medical practice work
Use these ten questions on every CPA on your shortlist. Compare the answers side by side. This is the practical version of the medical practice CPA Ontario checklist discussed above.
- How many Medical Professional Corporations did you set up or take on as clients in the last 12 months?
- Walk me through Ontario Regulation 665/05 share-ownership rules — who can hold voting and non-voting shares in my MPC?
- Why is the excluded-shares TOSI exception unavailable to a medical professional corporation, and which TOSI exceptions are actually available to me?
- How do you handle the OHIP remittance-to-general-ledger reconciliation in a monthly close?
- What is your passive-income plan for a physician with $200K/year of retained earnings — and how does s.125(5.1) enter your model?
- If I take locum shifts alongside my incorporated practice, how do you split my income and expenses across the two structures?
- Are you a Licensed Public Accountant (LPA)? If a bank refinance or clinic acquisition ever needs a review or audit report, can you sign it in-house or will I need a second firm?
- What is your written engagement letter, fixed fee, and quarterly cadence?
- What software do you use for bookkeeping (Xero, QBO, Sage), receipt capture (Dext, Hubdoc), and physician-friendly billing integration?
- What is your documented AI-governance policy, and how do you protect PHIPA-scope personal health information that touches financial workflows?
Any CPA who hedges on questions 2, 3, 5, or 7 does not do this work at depth. Print the list. Interview three CPAs. Sign with the one whose answers you understand and trust.
Comparison: general small-business CPA vs. medical-specialist CPA
This table compares categories of CPA — not named firms. Use it to test any CPA you shortlist.
| Dimension | General small-business CPA | Medical-specialist CPA |
|---|---|---|
| MPC setup + CPSO CoA filing | Occasional; may outsource | Routine; done in-house monthly |
| Ontario Reg 665/05 share-class fluency | Basic; likely refers to lawyer | Deep; drafts share structures with counsel |
| OHIP reconciliation | Rarely handled | Standard monthly workflow |
| TOSI for medical corporations | Often defaults to excluded-shares (wrong) | Applies excluded-business / reasonable-return / age-65 tests |
| Passive-income s.125(5.1) modelling | Awareness only | Annual forecast + IPP overlay |
| Locum T4A vs. T4 filings | Occasional | Routine |
| Family holdco structuring | Templated | Bespoke; tied to retirement horizon |
| Assurance (review/audit) capacity if MPC is a shareholder in a clinic | Referral to an LPA firm | In-house if the firm is LPA-led |
| PHIPA-aware document handling | General privacy policy | Documented workflow separating PHI from financial data |
The purpose of this table is not to imply general small-business CPAs are inadequate — many are excellent at what they do. It is to give a physician a concrete list of capabilities that must exist somewhere in the CPA relationship, and to help a physician decide whether one CPA can cover it or whether the practice needs a specialist plus an assurance referral.
Red flags that disqualify a CPA for medical work
Any two of the following flags is a signal to keep looking.
- “You can just pay a dividend to your spouse — the shares are excluded.” Wrong for medical corporations. See criterion 4 above.
- “You don’t really need a Certificate of Authorization renewal — CPSO doesn’t check.” CPSO does check, and a lapsed CoA means the MPC is not authorized to carry on the practice of medicine.
- No LPA in-house and no referral relationship. The day a bank or franchise wants a review-level financial statement, you will be scrambling for a second firm mid-year.
- Hourly billing with no cap and no written scope. A physician’s marginal hour is worth more at the clinic than negotiating fees with the CPA.
- Refusal to give you an engagement letter. CPA Canada Handbook requires it for every engagement. This is not negotiable.
- The CPA also handles kickback-style referral fees between healthcare providers. Referral fees between physicians and pharmacies, imaging clinics, or specialists are restricted under CPSO by-laws and can trigger both regulatory and tax consequences. A CPA who normalizes this practice is a CPA who will get you into trouble.
- No documented ethics wall between physician clients who refer to each other. A specialist and a referring family physician sharing a CPA is fine, but the firm should be able to describe how it manages conflicts and independence.
- They cannot name the current year’s OMA fee schedule change, the current-quarter CRA prescribed rate, or the current LCGE amount without checking notes. These are the physician-CPA equivalent of a physician not knowing this year’s CPSO renewal date.
When you need an LPA vs. a regular CPA
A Licensed Public Accountant (LPA) is a CPA who holds the Public Accounting Licence issued by CPA Ontario, authorizing the licensee to sign audit and review engagement reports on financial statements. Most physicians never need an LPA — a Notice-to-Reader compilation is sufficient for the annual T2 and personal tax cycle.
You need an LPA the day a stakeholder external to your practice will rely on your financial statements. Common triggers for physicians:
- Bank refinance or new loan facility with a review-engagement covenant.
- Buying into a group-practice clinic or specialty imaging centre that requires an audit for shareholder-agreement compliance.
- Selling shares in an MPC or clinic to a corporate buyer who requires audited financials in the diligence pack.
- A minority-shareholder dispute in a group practice that requires an independent review.
- Non-profit medical foundation board work under the Ontario Not-for-Profit Corporations Act.
Bader A. Chowdry, CPA, CA, LPA is one of approximately 250 practising Ontario LPAs. That means Insight Accounting CPA can carry a physician’s file from Notice-to-Reader through an in-house review or audit if the trigger event arrives, without a mid-relationship firm switch. Any LPA-led CPA firm can do the same — the point is to ask the question at engagement start, not the week your bank requests a review.
For a broader treatment of CPA selection outside the medical vertical, see the parent guide: How to Choose a CPA in Canada — 2026 Buyer’s Guide.
A composite example: Dr. K’s incorporation and TOSI restructure (anonymized)
Dr. K is a family physician in the GTA in her early 40s, married with two teenage children. Annual practice revenue $520K, direct expenses $110K, taking home $410K pre-tax through an unincorporated sole proprietorship. Spouse works part-time in an unrelated field earning $45K.
What a generalist CPA had recommended: incorporate, set up two classes of shares, pay Dr. K $180K salary, pay the spouse $60K dividend from non-voting shares under the “excluded-shares” TOSI exception.
Why that fails for a medical practice: the excluded-shares exception does not apply to professional corporations practising medicine. The $60K dividend to the spouse would be subject to TOSI at the top personal rate — approximately a $18K–$20K tax pickup rather than the assumed splitting benefit.
The physician-fluent restructure:
- Incorporate the MPC and apply for the CPSO Certificate of Authorization.
- Establish share classes compliant with Ontario Regulation 665/05 — voting Class A to Dr. K, non-voting Class B to spouse, Class C for future flexibility.
- Pay Dr. K a salary of approximately $175K — enough to maximize CPP contributions and RRSP room without triggering the top marginal bracket unnecessarily.
- Instead of a TOSI-exposed spousal dividend, establish a prescribed-rate loan from the MPC to the spouse (or to a family trust with the spouse as beneficiary) at the CRA prescribed rate — 3% in Q3 2026. The spouse invests the loaned funds; investment income is attributed based on the loan mechanics, not TOSI.
- Retain the balance of after-tax earnings in the MPC, monitoring adjusted aggregate investment income against the $50K–$150K passive-income band under s.125(5.1).
- Layer in an Individual Pension Plan (IPP) once salary supports it, shifting active-earnings deferral out of the passive-income pool.
- Model the eventual sale or wind-down against the 2026 LCGE of $1,275,000 — noting that MPC share sales require the qualified small business corporation share tests to be met over the preceding 24 months.
The result: legally defensible splitting, no TOSI reassessment risk on the spousal component, passive-income runway preserved, and a clean line to retirement optimization. This is one worked example — the right structure for any specific physician depends on age, spouse income, children’s ages, retirement horizon, and appetite for holdco complexity.
Frequently asked questions — how to choose a CPA for medical practice Ontario 2026
Q: What is a Medical Professional Corporation (MPC) in Ontario? An MPC is a corporation authorized to carry on the practice of medicine under the Medicine Act, 1991 and Ontario Regulation 665/05. It must hold a Certificate of Authorization issued by the College of Physicians and Surgeons of Ontario, and its share ownership is restricted to the physician member and specified family members.
Q: How much does a CPSO Certificate of Authorization cost in 2026? The new-application fee is approximately $400 and the annual renewal fee is approximately $175 as of 2026. Confirm current amounts on the CPSO Incorporation Issuance and Renewal page before filing.
Q: Can a physician pay dividends to a spouse from an MPC without triggering TOSI? Not automatically. The excluded-shares TOSI exception under s.120.4(1) of the Income Tax Act is specifically unavailable to professional corporations practising medicine. Dividends to a spouse are subject to TOSI unless another exception applies — most commonly excluded business (spouse works 20+ hours/week in the practice), reasonable return, or once the physician-shareholder reaches age 65.
Q: What is the passive-income small-business-deduction grind for an MPC? Under s.125(5.1) of the Income Tax Act, the $500,000 small business deduction is reduced by $5 for every $1 of adjusted aggregate investment income above $50,000 in the prior tax year, eliminated at $150,000. A physician-fluent CPA models this against retirement, investment, and IPP options before it becomes binding.
Q: How does a CPA reconcile OHIP payments in a physician’s books? Weekly OHIP remittance advices are matched to submitted fee codes; adjudicated rejects and holdbacks are recorded as receivable-in-suspense; Reconciliation Payments are booked to revenue in the period they relate to (not the period cash arrives). A CPA who has never done this monthly will misstate accrued revenue and cash timing.
Q: Do I need a Licensed Public Accountant for my medical practice? Most physicians do not — a compilation (Notice-to-Reader) prepared by any CPA is sufficient for the annual T2 and personal tax cycle. You need an LPA the day a bank, clinic partner, or acquirer requires a review or audit report on your financial statements.
Q: Can a locum physician be paid on a T4 instead of a T4A? Only if the CRA employee-vs-contractor factors point to employment. Most locum arrangements are contractor arrangements paid on T4A. A locum working exclusively at one hospital or clinic over a long period risks CRA reclassification and should discuss the fact pattern with a CPA before the fiscal year closes.
Q: What is the 2026 lifetime capital gains exemption on MPC shares? The LCGE for qualified small business corporation shares is $1,275,000 in 2026. QSBCS eligibility for an MPC is technical and requires 24-month asset and share-holding tests before the sale of shares — planning is done years, not months, in advance.
Q: Should my CPA also handle referral fees between me and other providers? Referral fees between physicians and other healthcare providers are restricted under CPSO by-laws and can carry both regulatory and tax consequences. A CPA who normalizes referral-fee practices as a matter of course is a red flag. Structure any inter-provider arrangement with legal counsel first, then bring it to your CPA.
Where to start
If you are a physician evaluating CPAs, print the ten-question checklist above and interview three firms. Look at the pattern of answers, not just the individuals. Ask each firm for a written engagement letter, a fixed fee, and a documented quarterly cadence before you sign.
If you would like to put Insight Accounting CPA through the same test, we welcome it. Book a 30-minute physician CPA fit-check at /start/, review our services and pricing pages, and see the vertical case study at Case study — locum physician saves $24K via mid-year incorporation and spousal income split. For a physician-vertical hub see /medical-practice-cpa-ontario-2026/; for the dental parallel see /cpa-for-dentists-ontario-2026/; for the broader Canada-wide buyer’s guide see /how-to-choose-a-cpa-canada-2026-buyers-guide/.
We are led by Bader A. Chowdry, CPA, CA, LPA — one of approximately 250 practising Licensed Public Accountants in Ontario — and we work with incorporated Ontario physicians, dentists, and other regulated health professionals. If your file is outside our specialties, we will tell you honestly and refer you to a firm better placed to serve you.
Reviewed by Bader A. Chowdry, CPA, CA, LPA — Insight Accounting CPA Professional Corporation, Mississauga ON. This article is general information for Ontario physicians and does not constitute accounting, tax, or legal advice for your specific situation. Please engage Insight Accounting CPA — or another Ontario CPA firm led by a Licensed Public Accountant — before acting on any information above.
Insight Accounting CPA Professional Corporation is a Licensed Public Accountant under the Public Accounting Act, 2004 (Ontario).
Important — informational only, not advice. Do not use this article to make any decision.
This article is published by Insight Accounting CPA Professional Corporation for general educational purposes only. It is not tax, legal, accounting, financial, or investment advice, and nothing in this article should be relied upon — by anyone, for any purpose — to make a business, tax, financial, accounting, legal, or investment decision.
Tax law, CRA administrative positions, court interpretations, and Ontario provincial rules change frequently, sometimes retroactively, and the content of this article may be incomplete, simplified, out of date, or wrong by the time you read it. The right answer for your specific situation depends on facts this article does not know — your structure, history, jurisdiction, filings, contracts, and goals.
Before acting, engage your own Chartered Professional Accountant or qualified advisor who has reviewed your specific circumstances in writing. Insight Accounting CPA Professional Corporation, the author, and any contributors expressly disclaim all liability — direct, indirect, or consequential — for any action taken or not taken on the basis of this content.
Insight Accounting CPA Professional Corporation is led by Bader A. Chowdry, CPA, CA, LPA — licensed by CPA Ontario under the Public Accounting Act, 2004. To engage us for situation-specific advice, book a free 30-minute discovery call.