The same Canadian tax system treats employment, business and investment income differently. If you receive a T4 salary, the useful question is which rules apply to your actual income and expenses—not whether there is a secret tax trick.
1. What would the new business investment proposal do?
On September 15, 2026, the federal government announced the proposed Productivity Mega Deduction: permanent immediate expensing for a broader range of eligible depreciable assets. The relevant deduction year is generally when an asset becomes available for use, rather than simply when it is paid for. The proposal targets eligible acquisitions from September 15, 2026, with exclusions including certain vehicles and other assets. This article describes the proposal; confirm the law and CRA guidance applicable when filing. Department of Finance backgrounder
Keep this separate from the earlier temporary small-business measure. For CCPCs, that measure covered eligible property acquired from April 19, 2021, and available for use before 2024, with a $1.5 million annual limit shared among associated businesses. Do not automatically carry that old limit into the new proposal. Finance Canada: earlier measure
A deduction is not reimbursement. If a $10,000 expense is fully deductible at an assumed 30% tax rate, a simplified calculation gives approximately $3,000 in tax savings—not $10,000. A purchase should first make sense for the business.
2. Genuine side-business income? Understand T2125
If you independently operate a consulting, professional-service or contract business alongside your employment, Form T2125 reports personal business or professional income and expenses. Employment status depends on the actual working relationship. Receiving a T4A alone does not establish self-employment, and T4A slips can report other income types. CRA: business or professional income
Reasonable business expenses may be deductible, including eligible home-office costs, phone expenses and the business-use portion of vehicle costs. Personal spending is excluded. Capital purchases, such as a computer, require a review of CCA or applicable immediate-expensing rules rather than automatically being treated as current expenses. CRA: business expenses
Keep invoices, payment records and business-mileage logs, and separate personal from business use. T2125 reports real business activity; it does not automatically convert salary into business income.
3. Investment-loan interest: potentially deductible, with conditions
CRA permits certain interest deductions on money borrowed to earn investment income; incorporation is not a prerequisite. The use of funds and supporting records matter. Interest on borrowing for investments that can produce only capital gains, or to contribute to registered accounts such as an RRSP, TFSA or FHSA, generally does not qualify under these rules. CRA: Line 22100
A tax deduction does not remove borrowing costs or investment losses. Consider income stability, repayment capacity, changing interest rates and market volatility. Have a qualified professional review fund tracing and deductibility. Borrowing solely for a tax deduction is not a sound reason to invest.
Start with your own income structure
List your employment income, genuine business income, planned business purchases and existing investment loans. Then review the rules that apply to each. A T4 does not necessarily rule out other deductions, but completing a form or incorporating does not create eligibility by itself.
To explore how these rules relate to your circumstances, book a consultation through Wallace Wang's main website to discuss your income structure, cash flow and long-term planning.
General educational information only, not individualized tax, legal or investment advice. Policy information reviewed September 26, 2026.