One Client, One Problem: The PSB Rule and Your Small Business Deduction

You incorporate to save tax. You work for one client because the work is good. Then CRA reclassifies your corporation as a Personal Services Business under ITA section 125(7). Your small business deduction disappears. Your tax rate jumps from roughly 12.2% on the first $500,000 to the general rate of 26.5%. Most expenses become non-deductible. That is the PSB trap.

The PSB rule applies when a CCPC has a single client, the individual performing work is a specified shareholder (10% or more), and the individual would reasonably be considered an employee without the corporate structure. CRA interprets this broadly. If 80%+ of your revenue comes from one client, you are in PSB territory. If you use their office, equipment, or cannot subcontract, the test tightens. Solo founders with one revenue source face a 90%+ probability of audit flag based on CRA's internal criteria.

The tax impact is severe. A solo founder earning $120,000 net through a regular CCPC in Ontario pays roughly $14,640 in corporate tax (12.2% small business deduction rate). That same founder classified as PSB pays $27,000–$31,800 (26.5% general rate). The difference: $12,360–$17,160 per year in additional tax. The small business deduction is a 19% rate advantage that PSB removes entirely.

Under PSB, almost every expense a solo founder relies on is disallowed. CRA lists what is deductible for a PSB: salary, wages, and employer CPP/EI contributions to the specified employee. Benefits like health insurance? Deductible. Everything else — rent, supplies, marketing, professional fees, vehicle, home office, meals, travel — is not. A founder claiming $30,000 in expenses in a regular CCPC deducts them fully. Under PSB, those $30,000 are added back to taxable income. The effective tax hit jumps by $8,000–$12,000.

The remedy requires structural changes. The single most effective protection: two or three active clients, each contributing a meaningful share. Not 90% from one and 10% from another. CRA's bright-line test looks for economic dependency that mirrors employment. Three clients at 40/30/30 passes. One at 95% does not.

Second protection: a risk of loss clause in every contract. If your contract says "fees are earned upon completion" and includes a penalty for late delivery or allows the client to withhold payment for defective work, you demonstrate entrepreneurial risk. CRA's PSB audit guidance specifically cites risk of loss as a mitigating factor.

Third: own your tools. Your own laptop, software licenses, accounting system, and office space. A solo founder paying $200/month for their own Notion, QuickBooks, and Zoom subscriptions spends $2,400 per year to maintain PSB protection. That $2,400 saves $12,000–$17,000 in potential tax penalties.

Fourth: subcontract. If your contract lets you subcontract and you do — even for one small piece — CRA considers that a strong indicator of independent business. A Toronto-based strategist had a single retainer at $14,000/month. We restructured: she subcontracted quarterly report production to a junior analyst for $1,200/month. That 8.5% subcontract demonstrated she was not an employee. Audit risk dropped from high to moderate.

A common myth: paying dividends instead of salary avoids the PSB trap. It does not. PSB classification examines the relationship between the corporation and the client, not the shareholder. However, salary does have one advantage: it is deductible to the PSB corporation. Dividends are not. If already classified as PSB, pay yourself salary up to the CPP maximum ($68,500) to optimize the deduction.

The incorporation breakeven for Canadian solo founders sits around $80,000–$100,000 annual net income. Below that, accounting costs for a T2 return ($1,500–$3,000 per year) often outweigh the deferral benefit. But above that threshold, PSB protection is not optional. It is structural.

Scelvara Lounge runs a PSB risk assessment in every Solo Strategy Canvas session for incorporated founders. Four variables: client concentration ratio, contract terms (risk of loss clause present or absent), tool independence, and subcontracting history. Output: a red-yellow-green risk rating and a two-action mitigation plan. The takeaway: incorporation without structural independence is just expensive employment.