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Engineering firm tax services: the T2, the C of A, and an honest read on SR&ED
Most of what a consulting engineering firm does is excellent engineering and ineligible SR&ED — applying known methods to a new site is standard practice, not experimental development. We tell firms that plainly, claim the credits that are real, and run the rest of the tax file properly: a clean T2 behind the PEO Certificate of Authorization, billing timing that matches milestone contracts, and HST that handles US clients correctly.
By the AnalytIQ Accounting team · Last reviewed: August 12, 2026
The corporate structure behind the Certificate of Authorization
An Ontario firm offering professional engineering services to the public needs a Certificate of Authorization from PEO, with a licensed engineer taking professional responsibility for the work. The C of A holder is usually an ordinary corporation, and its T2 follows the standard playbook: Ontario's combined 12.2% small business rate on the first $500,000 of active income, a salary-dividend mix for the principals set annually rather than by habit, and instalments trued up quarterly because project-driven income rarely repeats last year's pattern.
Two structural notes we check early. Firms that spin up separate corporations — one per discipline, or an operating company beside a holding company — are usually associated and share one $500,000 small business limit, so the second entity should exist for a business reason, not an imagined tax one. And the C of A conditions on who controls the practice are a licensing matter that any share reorganization has to respect before the tax logic even starts.
SR&ED for consulting firms: honesty first
SR&ED eligibility turns on technological uncertainty resolved through systematic investigation — not difficulty, novelty of the site, or tightness of the deadline. A firm applying established methods, codes, and software to a new project is doing what CRA calls standard practice, and claims built on that description fail technical review. Where consulting firms have genuine claims, they are usually narrow and specific:
| Work | SR&ED prospects |
|---|---|
| Designing to code with established methods, however complex the site | Not eligible — standard practice |
| Developing an in-house analysis tool where existing software demonstrably could not solve the problem | Potentially eligible — if the uncertainty and the attempts are documented as they happen |
| A novel material, process, or design approach tested because established ones failed | Potentially eligible — the failures are the evidence |
| Experimental work a client paid for under the contract | Contract payments reduce your claim — often the client, not you, has the real claim |
That last row is the one consulting firms miss. When a client funds the work, contract payments grind down your eligible pool, and the economics of the claim often belong to whoever bore the cost and kept the rights. Where a claim is real, a CCPC earns a 35% refundable federal credit plus Ontario credits on top — worth documenting properly with contemporaneous records, and not worth stretching. A firm known to CRA for one disallowed claim buys reviews of the next five.
Milestone billing, holdbacks on your fee, and year-end
Engineers, like architects, were never on the list of professions that could elect billed-basis accounting — so unbilled work has always been on the tax table, and the year-end cut-off deserves real attention. Fees earned by milestone are income when the milestone is reached; amounts invoiced ahead of the work sit as deferred revenue until it is done; and unbilled work at year-end enters income as WIP at the lower of cost and fair market value — cost meaning the direct salaries behind the unbilled hours. Where a client contract holds back a percentage of your fee pending project completion, the holdback is generally not income until it becomes receivable under the contract, which is a timing difference worth tracking deliberately on multi-year infrastructure work. We reconcile the project-management system to the ledger at year-end so the T2's revenue picture matches what the contracts actually say — and the same schedule serves the bank and the bonding company, who read WIP as closely as CRA does.
HST, US clients, and where the Canadian return stops
Consulting fees to Canadian clients carry HST at the client province's rate, and the firm recovers tax on its own inputs as ITCs — routine, provided sub-consultant flows run through the books. Fees to a non-resident client for work on a US project are typically zero-rated, which drops the tax but not the paperwork: the file needs evidence of non-residence, and the US side may want a W-8BEN-E, worry about state nexus from site visits, or ask for a protective US filing. That layer — including how SR&ED interacts with US contract revenue — is covered in our cross-border tax guide for engineering firms. The full shape of our compliance work is on the tax services page.
Source: CRA — SR&ED tax incentive program.
Common questions.
Our projects are genuinely hard. Why might they not qualify for SR&ED?
Because eligibility turns on technological uncertainty, not difficulty. Applying established methods and codes to a demanding site is standard practice in CRA's framework. Claims survive when existing approaches demonstrably could not work and the systematic attempts to resolve that are documented as they happened.
A client paid for our experimental work — can we still claim it?
Usually not in full. Contract payments reduce your eligible expenditure pool, and the claim often belongs to the party that bore the cost and kept the rights. We read the contract before anyone counts the credit.
Do we charge HST to a US client?
Fees to a non-resident client for a US project are typically zero-rated — no HST, full input tax credits — but you need proof of non-residence on file, and the engagement may raise US questions like W-8BEN-E forms or state nexus from site work.
Related reading
Real credits claimed, nothing invented.
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