The agency model, and why incorporation is usually the agency's idea
In the standard placement, the agency holds the contract with the end client and you hold a contract with the agency, so your corporation invoices the agency, the agency invoices the client with a margin on top, and the client never pays you directly. Most agencies will only place you two ways: on their own payroll as a T4 employee of the agency, or through a corporation you own. Many will not place an unincorporated contractor at all, and the incorporation requirement is usually presented as standard, which it is, but the reason it is standard belongs to the agency rather than to you.
The reason is payroll exposure. Under the CPP and EI rules, a worker placed by an agency to perform services under the direction and control of the client is treated as the agency's employee for contributions and premiums, unless a corporation stands between the worker and the agency. An incorporated contractor takes that obligation off the agency's books, along with vacation pay, termination notice and the other consequences of employment. The corporation is therefore doing a job for the agency on day one; whether it also does a job for you is the question this page answers, and the answer depends on facts the agency's onboarding form does not ask about.
None of this makes the arrangement improper or the agency adversarial. Agencies sell staffing, the end client wants a flexible resource without a headcount, and the corporate structure is how that market works in Canada. What it means is that the incorporation decision has already been made for the agency's reasons, and the tax consequences of that decision fall on you.
Why the placed IT contractor is the classic PSB fact pattern
An incorporated contractor working full-time at one end client, on the client's laptop, inside the client's systems, at an hourly or daily rate set by the agency, with a manager assigning tickets and approving time off, is the arrangement the personal services business rules were written to catch. Every test points the same way: the client controls the work, supplies the tools, carries the financial risk and integrates you into the team. The corporation's only function is to receive the invoice, and a corporation whose owner would plainly be the client's employee without it is a personal services business, taxed at roughly 44.5 per cent on its profit with almost no deductions.
The agency chain adds two aggravating facts. The agency's contract with the end client, which you rarely see, usually describes supervision, hours, site attendance and a right to replace you, in language written to satisfy the client's procurement department rather than the tax tests. And the sequence of placements that makes up a contracting career, six months here, a year there, never produces concurrent clients, because you have one end client at a time however many names accumulate. Why a long list of past placements does not count as multiple clients, and what genuinely concurrent clients look like, is the subject of does having more than one client protect you from the PSB rules.
The practical conclusion is not that you should refuse to incorporate; it is that you should incorporate without expecting the tax outcome that incorporating gives other businesses. The corporation of a placed contractor is, for tax purposes, usually a payroll vehicle with a corporate return attached. Plan it that way from the start and it is inexpensive; plan it as a tax shelter and it becomes an audit.
The honest math: when incorporation still helps
Incorporation still helps a placed contractor in four situations, only one of which is about tax deferral, and the first is the rate. Agencies and clients typically pay an incorporated contractor a daily or hourly rate above what the same work earns as a T4 placement, because they are not paying vacation, statutory holidays, benefits, employer CPP and EI, or severance on a corporate contract. That premium is real money, and it is yours whether or not the corporation ever shelters a dollar of tax. When the premium exceeds the corporation's running costs, incorporation pays for itself on the contract terms alone.
The second is deferral, and it exists only if the corporation is not a PSB. A contractor with genuinely independent facts, fixed-price deliverables, their own equipment, concurrent clients and the right to substitute, retains profit at 12.2 per cent and defers personal tax on it, which is the standard case for incorporating a consultancy and is set out in should a consultant incorporate in Ontario. Be honest about whether that is you. If it is not, the deferral is not merely unavailable; reaching for it is what creates the reassessment.
The third is income splitting, and it is narrower than the forums suggest. Dividends to a spouse or adult children from a services corporation are caught by the tax on split income rules and taxed at the top rate unless an exclusion applies. The reliable exclusion is a family member who actually works in the business an average of at least 20 hours a week; once the owner is 65 or older, amounts to the owner's spouse are also excluded, and the excluded-shares route generally does not work where the corporation's income is mostly from services. For a solo contractor, splitting is usually limited to paying a family member a reasonable salary for real work, which is deductible even to a PSB.
The fourth is liability. The corporation puts the agency contract and any commercial obligations in the company's name, so a dispute over a deliverable or a terminated engagement reaches corporate assets before personal ones. It does not protect you from claims about your own negligent work, which is what errors-and-omissions insurance is for, and most agency contracts require that insurance regardless. Treat the shield as real but modest.
When a T4 placement or a sole proprietorship is better
A T4 placement is better when the rate premium for incorporating is small, when you value EI coverage and simplicity, or when the engagement is short. A sole proprietorship is better when the agency permits it, because the personal services business rules apply only to corporations: a sole proprietor's business income is taxed once at personal rates with ordinary business deductions, and the risk shifts to being treated as the agency's employee under the placement rules rather than to a punitive corporate rate. The corporation earns its place when the premium is large, the engagement is long, and the facts have some chance of moving toward genuine independence.
| T4 placement with the agency | Sole proprietor | Your own corporation | |
|---|---|---|---|
| Who pays you | The agency, on payroll | The agency pays your business | The agency pays your corporation; your corporation pays you |
| Rate | Lowest; benefits and statutory costs come out of it | Higher; often not offered by agencies | Highest; the agency's usual preferred structure |
| Tax on profit | Personal rates, withheld at source | Personal rates, with ordinary business deductions | 12.2 per cent if genuinely a business; roughly 44.5 per cent if a PSB, with salary as the escape |
| CPP and EI | Both, shared with the agency | CPP both halves; no EI | CPP both halves through your payroll; no EI |
| HST | None | Register and charge once over the small-supplier threshold | Register and charge; the agency recovers it |
| Compliance cost | None | A business schedule on your personal return | Corporate return, payroll, HST, minute book |
| Deferral | None | None | Only if the corporation is not a PSB |
The comparison most contractors never run is the corporation as a PSB against the T4 placement. Once the corporation pays all its profit out as salary, its tax result is close to the T4 result: the same personal tax, CPP paid in full rather than shared, no EI, plus the cost of a corporate return and payroll filings, offset by the rate premium and whatever the corporation's genuinely allowed expenses save. If the premium is worth more than those costs, incorporate. If it is not, the corporation is a fee you pay for the agency's convenience.
HST registration and the agency
Your corporation must register for HST once its taxable revenue passes the 30,000 dollar small-supplier threshold, and for a contractor billing a full-time rate that happens within the first quarter, so register at incorporation and be done with it. You charge HST on every invoice to the agency; the agency, as a registrant, recovers it as an input tax credit, so it costs the agency nothing and is not a negotiating point. You then recover the HST on your own costs, and that recovery is unaffected by any personal services business finding, because the income tax denial of deductions does not reach the HST rules.
Agencies usually specify how invoices must be presented, including your HST number, the period, the approved hours and the rate, and they pay on their own cycle, often 30 days or more after the client approves the timesheet. Your corporation is carrying that receivable, which is a business risk, and it is worth noting in your file as one. Filing frequency is annual by default at your revenue level, with instalments once the balance is large enough; some contractors elect quarterly filing to keep the remittance from becoming a lump. The simplified quick method of accounting may be available to an IT contractor and sometimes leaves a small margin, but it is a calculation rather than a default, and it stops paying off once the corporation carries meaningful HST-bearing costs.
The salary-first discipline, and what changes the answer
If you incorporate as a placed contractor, pay yourself salary from the first month and leave as little profit in the corporation as your cash needs allow. Salary and benefits paid to you are the only deductions a PSB keeps, so a corporation that clears its profit through payroll each year has almost nothing exposed to the 44.5 per cent rate even if CRA later applies the label; a corporation that accumulates profit at 12.2 per cent and pays dividends is the one that gets the expensive letter. The discipline costs you the deferral, and on placed-contractor facts the deferral was never safely yours.
The salary route also builds RRSP room and CPP entitlement, which a dividend-paid contractor accumulates none of, and it produces the T4 income lenders want to see when the mortgage application comes. Run it properly: a payroll account, monthly salary, a year-end bonus for the remainder paid within 180 days of the year-end, T4s filed by the end of February. Adjust the retained amount upward only as the facts change, a second concurrent client, your own tools, a fixed-price statement of work, and adjust it back when a renewal reintroduces exclusivity or full-time hours.
The facts that change the answer:
- The size of the rate premium over a T4 placement: the whole commercial case for the corporation, measured against its running costs.
- Whether the agency permits any structure other than a corporation: if not, the question is how to run it, not whether to have it.
- Engagement length and the number of concurrent clients: a long placement at one client is the PSB pattern; genuine parallel work changes it.
- Who supplies the tools and controls the day: the client's laptop and manager, or your own equipment and method.
- Family members who genuinely work in the business: real hours support a deductible salary; nothing else supports splitting.
- Your appetite for the fight: an incorporated contractor who wants deferral has to build the facts for it and defend them, year after year.
We set up placed contractors' corporations with the payroll, HST and salary policy built in from day one, and we tell you plainly when the corporation is not worth having; that work is described in IT consultant incorporation. If an agency has told you to incorporate and you want the honest math before you sign, a free 15-minute discovery call is where it starts.
