Accounting Firms in Mississauga: How to Compare Them (2026)

Reviewed by Bader A. Chowdry, CPA, CA, LPA on September 19, 2026

Search for an accounting firm in Mississauga and you will get a page of results that are almost impossible to tell apart. Similar service lists, similar designations, similar photographs of similar boardrooms. Nothing on those websites answers the question you actually have, which is not “who is good” but “which of these can do the specific thing I need, and what should it cost”.

There is a real answer, and a surprising amount of it is written into Ontario legislation rather than into anyone’s marketing. This page sets out the three criteria that separate firms in practice — legal scope, engagement type, and fee model — and how to check each one before you make a call.

What actually differs between one Mississauga accounting firm and another?

Less than the marketing suggests, and more than most owners check. Every firm here files T2s and payroll. The real differences are three: whether the firm holds an Ontario public accounting licence, which engagement standards it is set up to perform, and how it prices. Those three decide whether a firm can serve you at all — not how good it is.

That distinction matters more than it sounds. Most comparison advice treats the licence as a quality badge, as though licensed firms are the serious ones and everyone else is second tier. That is not what Ontario law says, and getting it backwards leads owners to disqualify capable firms for no reason while failing to ask the one question that would actually narrow their list.

The first fork is scope. Ontario restricts a specific, narrow category of work — broadly, the work where an outside party relies on financial statements you present — and leaves everything else open. Bookkeeping, corporate and personal tax returns, HST filings, payroll, advisory, forecasting, and reorganisation planning are all outside the restricted category. So a firm’s licence status tells you what it may sign, not what it may do, and certainly not how well it does it.

If you have already settled on wanting a CPA and are choosing between individual practitioners, our guide to choosing a CPA for a small business in Mississauga works through that decision. This page is about comparing firms as organisations.

What does a public accounting licence in Ontario actually let a firm do?

Under the Public Accounting Act, 2004, s.2(1), the practice of public accounting means providing, independently, either assurance engagements — including an audit or a review engagement — or compilation services, where a third party can reasonably be expected to rely on the result. Section 3(1) requires an individual doing that work to be licensed, and the firm to hold a certificate of authorization.

Two features of that definition are easy to miss and both change how you read a firm’s credentials.

Independence sits inside the definition, not beside it. The statute says the services must be provided “on a basis that is independent of the person for whom the services are being provided”. Independence is not a professional courtesy layered on top of public accounting; it is part of what the term means. A firm that keeps your books all year and then reports on those same statements has an independence problem to solve, not merely a preference to declare.

An assurance engagement does not require an opinion. Section 2(2) provides that assurance engagements “may or may not include the rendering of an opinion or other statement by the person who is providing the services.” So the absence of a signed opinion page is not evidence that no licence was needed. The trigger is third-party reliance, not the format of the report.

Then comes the provision that most comparison articles omit entirely, and that changes the whole picture.

The s.2(3) carve-out. Where a compilation and its associated materials carry a notice in the prescribed form providing that any assurance given is limited to the accuracy of the computations required to complete the compilation, section 2(3) says the provision of those compilation services “does not constitute public accounting for the purposes of this Act.” In plain terms: a properly noticed compilation is not public accounting, so it does not require a licence. That is the statutory basis on which a great many capable, entirely lawful Ontario firms operate without one. They are not cutting corners. They are working inside a carve-out the legislature wrote deliberately.

The licence requirement also has a narrow exception in section 3(2), for persons providing public accounting services exclusively in respect of a public authority or Crown corporation, a bank or loan or trust company, a transportation company incorporated by an Act of the Parliament of Canada, or a publicly-owned or publicly-controlled public utility organization. It is worth knowing the exception exists, but it will almost never describe an owner-managed Mississauga business.

On eligibility, section 4(1) provides that to be eligible for a licence a person must be a member of CPA Ontario, and section 4(2) revokes the licence on the day the person ceases to be a member. Section 11(1) permits licensed individuals and partnerships to establish a professional corporation to practise public accounting. This is why the register, rather than a website, is the thing to check — membership and licence move together.

The engagement standards themselves are worth knowing by name, because they are what a lender or board will actually specify:

• CAS — Canadian Auditing Standards, for audits. The highest level of assurance.
• CSRE 2400 — for review engagements. A moderate, limited level of assurance.
• CSRS 4200 — for compilation engagements. No assurance on the underlying information. This standard replaced the former Section 9200 “Notice to Reader” communication, which is why a compilation report today looks materially different from one issued years ago, and why a lender working from an old template sometimes asks for a document that no longer exists.

The reframe worth carrying into your shortlist: the licence tells you what a firm may sign, not how well it works.

Do I need an audit, a review, or a compilation?

Usually someone else decides this for you. A lender, a franchisor, a bank covenant, a board, a grant agreement or a shareholders’ agreement names the engagement it will accept. Read that document before you call anyone. If nothing external requires assurance, a compilation is normally the right and cheapest answer, and the licence question stops mattering.

Who is asking	What they usually specify	What that means for your shortlist
Nobody — internal use and CRA only	No assurance required	Compilation; the licence question is moot
Bank or lender, small facility	Review engagement, sometimes compilation	Firm must be licensed for a review
Bank or lender, larger facility or covenants	Audit	Firm must be licensed, and staffed for audit
Franchisor, grantor, or regulator	Named in the agreement — read it	Match the named engagement exactly
Condo corporation, charity, or NPO board	Set by statute or by-law	Confirm before shortlisting

This table describes who typically asks, not what the law requires of you — the requirement comes from whichever agreement or statute applies to your own situation, and the hedging in the middle column is deliberate. The practical sequence is: find the document that names the engagement, read the clause, and only then start comparing firms. Owners who do it the other way round routinely shortlist on price, sign, and then discover the engagement they bought is not the one their lender will accept.

How should I compare fees between Mississauga firms?

Compare the scope, not the number. A fixed annual fee and an hourly estimate are not the same product, and neither is comparable until you know what is inside. Ask each firm for the same written scope: which returns, which engagement, how many entities, how many bank accounts, who does the bookkeeping, and what triggers a fee outside the quote.

Four pricing models are common in this market, and each is a reasonable choice for a different kind of client:

• Fixed annual fee. Predictable, easy to budget, and it rewards you for being organised. Scope creep is handled by a change order rather than a surprise.
• Hourly. Flexible and fair where the work genuinely cannot be estimated, but the number you are quoted is an estimate, not a price.
• Per-engagement. Common where a discrete piece of work — a review, a reorganisation, a valuation — sits alongside ongoing compliance.
• Monthly retainer. Suits businesses that want year-round access and bookkeeping bundled rather than an annual event.

None of these is superior in the abstract. What makes a quote comparable is the scope behind it, so ask every firm to price the same written list:

1. The T2 return, and which schedules are included.
2. Personal T1 returns, and for which shareholders and spouses.
3. HST returns, and the filing frequency.
4. Payroll processing and the annual information returns.
5. Bookkeeping — in scope or yours to provide, and in which software.
6. The engagement type from the section above, named explicitly.
7. Year-end adjusting entries and the working-paper file.
8. CRA correspondence, review letters, and who handles them.
9. Planning time, and whether a mid-year call costs extra.

One more point, because it is the most expensive thing on this page. The cheapest compliance quote can be the costliest choice over a decade, and not because of the fee. A corporate reorganisation, a family share issuance or a business sale that was structured without advice is expensive to unwind. The lifetime capital gains exemption on qualified small business corporation shares — $1,275,000 for 2026 — turns on conditions tested over a period of time, not on the day you decide to sell. A firm that never asks about your plans cannot flag the problem three years before it matters. CRA’s small business and self-employed hub is a reasonable starting point for the compliance baseline; the planning layer is what you are actually buying.

For current fee ranges by service and entity size, see what a CPA costs in Ontario.

What can I verify about a firm before I call?

More than most people check, and all of it free. CPA Ontario publishes whether a firm holds a public accounting licence. The CRA publishes the filing status of every registered charity. Your own corporate filings tell you whether previous advisors kept the registry current. Verify first, then use the call to ask about fit.

• The CPA Ontario member and firm register. Check the licence, not the logo. A designation on a website tells you someone is a CPA; the register tells you whether the firm holds a public accounting licence or certificate of authorization, which is the question that decides whether it can perform the engagement you need.
• If you are a charity or a not-for-profit, the CRA’s List of charities and certain other qualified donees shows registration status and whether filings are current — useful for checking your own organisation before a board meeting as much as anyone else’s.
• Your own filing obligations, so you can judge whether a proposed timetable is realistic. A corporation resident in Canada files its return within six months after the end of the taxation year under ITA s.150(1)(a), and CRA’s corporation income tax return page sets out who has to file. Note that the payment deadline is separate and earlier for many corporations — a firm that treats the filing date as the only date is planning your cash flow badly.
• The statute itself, if you want to check anything on this page: the Public Accounting Act, 2004 is published in full on Ontario e-Laws.
• How long your records have to support the file. Under ITA s.152(3.1), CRA can generally reassess within three years of the original notice of assessment for a Canadian-controlled private corporation, and four years for a corporation that is not one — the subsection carries carve-outs, so treat those as the general case rather than an absolute. That window is why continuity of records, and a clean handover when you change firms, is worth asking about before you engage anyone.

Does size matter — sole practitioner, small firm, or national?

Size changes three things: continuity, capacity, and who actually does your work. A sole practitioner offers one consistent relationship and a single point of failure. A multi-partner firm offers coverage and specialisation, with more handoffs. A national firm brings depth you may never use. Match the structure to how complicated your business actually is, not to how large you hope it becomes.

A sole practitioner. You speak to the person doing the work, every time, and nothing is lost in translation. The limitation is structural rather than professional: illness, leave or a busy season lands on one desk, and depth in an unusual area may have to be bought in.

A small or mid-sized multi-partner firm. Coverage during absences, a second opinion in the building, and usually some genuine specialisation by industry or engagement type. The trade is that the person who sells the work is often not the person who does it, and continuity depends on staff turnover rather than on one individual.

A national or international firm. Real depth in complex areas, formal quality-management systems, and the capacity to handle a group of entities or a cross-border structure. The trade is cost, and the risk that a straightforward owner-managed file is neither interesting nor profitable enough to attract senior attention.

Four questions cut through all three:

1. Who does the work, and who sold it? Ask for the name and the designation of the person who will actually prepare the file.
2. What happens during a personal leave or a busy season? Ask for the specific arrangement, not a reassurance.
3. How many businesses like mine does the firm handle? Same entity count, same industry, same engagement type.
4. What is the handover process if we part ways? A firm confident in its work will describe this without hesitation, because it happens routinely and reflects on nobody.

If your real question is day-to-day support rather than year-end compliance, bookkeeping is where to start instead. And if you are choosing between individual practitioners rather than comparing organisations, the small-business CPA selection guide covers that ground.

Case study: when the bank, not the firm, forced the change

Anonymised and non-identifying.

A Mississauga distribution company with two operating entities approached its bank for an equipment facility. The term sheet came back specifying a review engagement on the consolidated statements. The company’s incumbent provider — entirely properly — performed compilations under the s.2(3) notice and was not licensed for assurance work. The engagement had to move.

The useful point is the sequencing, not the outcome. Nothing was wrong with the incumbent’s work: a noticed compilation was the correct product for a company whose statements had never been relied on by an outsider. What changed was the audience. The moment a lender was going to rely on those statements, the engagement crossed into the territory section 2(1) restricts, and the licence question became the only question that mattered.

Reading the term sheet three months earlier would have turned a rushed mid-year transition — new firm, new working papers, a first-year engagement under time pressure, and two sets of professional fees in one year — into an orderly planned change. The lesson for a shortlist is simply this: find out what the engagement has to be before you decide who performs it.

Frequently Asked Questions

Q1. Does every accounting firm in Mississauga need a public accounting licence?

No. Under the Public Accounting Act, 2004, s.2(1), the licence is required for assurance engagements and for compilations a third party will rely on. Section 2(3) excludes compilations that carry a notice in the prescribed form limiting any assurance to the accuracy of the computations. Bookkeeping, tax return preparation and advisory work fall outside the definition entirely.

Q2. What is the difference between an audit, a review and a compilation?

An audit gives the highest level of assurance and a review a moderate, limited level; both are assurance engagements under s.2(1) and require a licensed practitioner. A compilation assembles information you provide into financial statement format without providing assurance on the underlying information.

Q3. Which standard applies to a compilation engagement in Canada?

CSRS 4200, Compilation Engagements, which replaced the former Section 9200 “Notice to Reader” communication. A compilation report prepared under the current standard therefore reads differently from an older Notice to Reader, which occasionally surprises a lender working from a dated checklist.

Q4. How do I check whether a Mississauga firm is licensed?

CPA Ontario maintains the register of members and of firms holding a public accounting licence or certificate of authorization. Check the register rather than relying on the designations shown on a website — under s.4(2) a licence is revoked the day CPA Ontario membership ends.

Q5. When is my corporation’s tax return due?

A corporation resident in Canada files within six months after the end of its taxation year, under ITA s.150(1)(a). That deadline is the same regardless of which firm prepares the return. Payment deadlines are separate and earlier for many corporations.

Q6. Is a firm without a public accounting licence a worse firm?

No — the licence is about scope, not quality. Section 2(3) of the Public Accounting Act, 2004 expressly provides that a compilation carrying the prescribed notice is not public accounting, so an unlicensed firm doing bookkeeping, tax and noticed compilations is operating exactly as the legislation contemplates. The right question is whether you need assurance, and only then whether a given firm can provide it.