Cross-Border Business Traveler: Short-Term Assignment Tax Rules (Canada-US)

A Canadian employee who travels to the US for business (client meetings, a project site, a training program, a temporary secondment) creates a potential US tax obligation from day one. Under US domestic law, compensation for services performed in the US is US-source income, taxable regardless of how short the trip is. The Canada-US treaty provides an exemption (Article XV) that can eliminate the US tax if certain conditions are met, but the exemption is not automatic, and the employer may still have withholding obligations.

How does the 183-day test work?

The treaty’s 183-day test counts days of physical presence in the work country during any 12-month period that begins or ends in the applicable fiscal year. For the US, the fiscal year is the calendar year.

Key points:

• Any purpose counts. Days spent in the US for business, vacation, or transit all count toward the 183-day total. It is not limited to workdays.
• The 12-month period is rolling. Unlike the substantial presence test (which uses a 3-year weighted formula), Article XV looks at any 12-month period. A traveler who spends 90 days in the US from July to December 2025 and 95 days from January to June 2026 has exceeded 183 days in the July 2025 to June 2026 period, even though they were under 183 in each calendar year.
• Part-day counts as a full day. Arriving in the US at 11 PM counts as a day of presence.

If the 183-day condition is met (presence exceeds 183 days), Article XV does not apply, and the work country can tax the income. The other two conditions become irrelevant.

Who is the employer for Article XV?

The second condition requires that the remuneration be paid by, or on behalf of, an employer who is not a resident of the work country. For a Canadian employee of a Canadian company traveling to the US:

• If the Canadian company sends the employee to the US and continues paying them from Canada, the employer is a Canadian resident. Condition 2 is met.
• If the Canadian company has a US subsidiary, and the US subsidiary is the legal or economic employer (directs the work, bears the cost, controls the day-to-day), the employer may be treated as a US resident. Condition 2 fails.
• If the Canadian company charges the cost of the employee’s services to a US client or US affiliate under a cost-sharing or secondment arrangement, the CRA and IRS may argue that the remuneration is “borne by” the US entity’s permanent establishment. Condition 3 fails.

The practical challenge for multinational employers is that intercompany charge-backs for employee time can convert a short-term trip into a taxable event in the work country, even if the employee is present for only a few weeks.

What are the employer’s withholding obligations?

Even when the Article XV exemption applies, the employer may still have a withholding obligation:

US withholding on a Canadian employee working in the US:

• Under US domestic law, an employer paying wages for services performed in the US must withhold federal income tax (and applicable state tax). The treaty exemption does not automatically override this.
• To stop withholding, the employee files Form 8233 with the employer, claiming the Article XV exemption. The employer forwards the form to the IRS. If the IRS does not object within 10 business days, the employer can stop withholding.
• Some employers choose to withhold anyway and let the employee claim a refund on Form 1040-NR. This is conservative but avoids risk for the employer.

Canadian withholding on a US employee working in Canada:

• A US employee sent to Canada triggers Canadian employer obligations if the Canadian entity is the employer or if the US employer has a PE in Canada. The CRA’s Regulation 102 waiver process allows the employer to reduce or eliminate Canadian withholding when the Article XV exemption applies.
• Without the waiver, Canadian withholding applies at graduated rates on the Canadian-source portion of the compensation.

What about state and provincial tax?

The treaty exemption applies only to federal tax. State and provincial tax obligations run separately:

• US state tax. Most states with an income tax require withholding from day one on wages for services performed in the state. Some states (like New York) have no de minimis exception for business travelers. Others (like Illinois) apply a threshold or convenience-of-the-employer rule. A Canadian business traveler to New York for 3 days may owe New York state tax on the 3 days of wages, even if the federal tax is exempt under the treaty.
• Canadian provincial tax. Provincial tax follows the same rules as federal: if the employment income is exempt under the treaty, the provincial tax does not apply separately (the province piggybacks on the federal determination).

The state income tax guide covers the state-level obligations in more detail.

What if I cross the border frequently?

Frequent business travelers (weekly trips, commuters, consultants who split time) face a cumulative tracking problem. Every day in the work country counts, and the 183-day threshold can be reached faster than expected. Employers with employees who regularly cross the border typically implement a day-tracking system and allocate compensation based on workdays in each country.

• For a Canadian who commutes daily from Windsor to Detroit, or from Vancouver to Seattle, the 183-day threshold is reached in about 6 months. Once exceeded, Article XV no longer applies, and the compensation for all US workdays in that 12-month period is US-taxable (with an FTC on the Canadian return to prevent double taxation).
• The cross-border payroll guide covers the employer’s obligations for split-jurisdiction employees.

What should I do next?

If you travel to the US (or Canada) for business, track your days of physical presence in the work country. If you are under 183 days and the other Article XV conditions are met, file Form 8233 (for US work) or request a Regulation 102 waiver (for Canadian work) to avoid unnecessary withholding. If you exceed 183 days, the work-country income is taxable, and the FTC on the other country’s return prevents double taxation.

• Form 8233 withholding exemption, claiming the treaty exemption at source
• Cross-border payroll and employer withholding, the employer’s obligations
• Substantial presence test, the US residency test (different from the 183-day treaty rule)
• State income tax for cross-border workers, state-level obligations for business travelers
• Tax equalization for cross-border employees, employer-managed tax programs
• Moving from Canada to Georgia, film industry assignments and permanent relocations to Atlanta

This guide is general information, not tax advice for your specific situation. Which points apply, and how, depends on your facts.