When Canada and South Dakota Meet
BOMCAS is based in Edmonton and works on both sides of the border, which makes cross-border files a natural fit. South Dakota does not touch Canada, but North Dakota is all that separates it from Manitoba and Saskatchewan, and its ties to Canada come through trade, agriculture, construction, tourism and family. A Canadian manufacturer shipping to Sioux Falls, an Alberta contractor on a South Dakota job, a Canadian who owns a cabin in the Black Hills, or a U.S. citizen living in Canada with family in Rapid City each has a different set of filings. We look at the full picture so the U.S. and Canadian returns agree.
Canadian Businesses Selling Into South Dakota
South Dakota's remote seller rules apply to foreign sellers too. A Canadian business with no physical presence in South Dakota must register and collect South Dakota sales tax once its gross revenue from sales delivered into the state exceeds $100,000 in the current or previous calendar year. Because South Dakota taxes most services as well as goods, Canadian service providers such as software, marketing or design firms can be caught as well. Sales through a marketplace provider are generally collected by the marketplace. We test the threshold, handle registration and file the returns.
At the federal level, a Canadian company selling into the United States is generally protected from U.S. income tax under the Canada–U.S. tax treaty unless it has a permanent establishment in the U.S. A company that relies on the treaty may still need to file a U.S. return disclosing that position. U.S. customers usually ask Canadian suppliers for Form W-8BEN-E to document their status.
Canadian Contractors and Crews on South Dakota Projects
Construction and installation work brings different rules. A Canadian prime contractor on a South Dakota realty improvement project needs a South Dakota contractor's excise tax license and pays the 2 percent excise tax on gross receipts. Materials brought in from Canada may owe South Dakota use tax. Employees working in South Dakota bring U.S. payroll questions, including reemployment assistance registration with the state. A long project can also create a permanent establishment under the treaty, which changes the federal income tax answer. We review the contract before the work starts, when the options are widest.
Individuals: Residency, the Treaty and Filing
Canadians spending time in South Dakota
A Canadian who spends long periods in the United States can become a U.S. resident for tax purposes under the substantial presence test, which counts days over a three-year period. Canadians who meet the test but keep their main ties in Canada can often claim a closer connection to Canada by filing Form 8840, or rely on the treaty's tie-breaker rules. Counting days carefully each year avoids surprises.
U.S. citizens living in Canada
U.S. citizens must file a U.S. return every year wherever they live, along with their Canadian return. Foreign tax credits usually prevent double tax, but the two returns need to be prepared together. Anyone with a financial interest in, or signing authority over, foreign accounts totalling more than $10,000 at any time in the year must file an FBAR (FinCEN Form 114). It is due April 15, with an automatic extension to October 15.
Registered plans
RRSPs and RRIFs receive treaty treatment that defers U.S. tax on their growth for U.S. filers. TFSAs and RESPs are not covered in the same way, and they can create extra U.S. reporting. We review registered plans before a move in either direction.
Property in South Dakota Owned From Canada
Canadians who rent out South Dakota property face U.S. tax on the rent. Without an election, 30 percent of the gross rent is withheld. Most owners do better by electing to be taxed on net rental income and filing a U.S. nonresident return each year. When the property is sold, the buyer generally must withhold under FIRPTA unless an exception or reduced withholding certificate applies. On the Canadian side, the property is reported on the owner's return, and Canadians whose specified foreign property costs more than $100,000 in total file Form T1135. Foreign tax credits connect the two returns.
Moving Between Canada and South Dakota
Moves in either direction need planning. Leaving Canada can trigger a deemed disposition of property and a final Canadian return. Arriving in South Dakota means no state income tax, but federal U.S. tax on worldwide income begins at residency. Moving from South Dakota to Canada brings Canadian tax on worldwide income and the start of foreign reporting. We plan the timing of the move, asset sales and plan withdrawals so the transition is efficient.
How We Work Cross-Border Files
We start by mapping where each person and entity is resident, where income comes from and which treaty articles apply. Then we prepare the U.S. and Canadian filings together. Every cross-border file depends on its facts, and this page is general information, not advice for a particular situation.
South Dakota Cross-Border Tax Questions
Does a Canadian business have to collect South Dakota sales tax?
Yes, if its gross revenue from sales delivered into South Dakota exceeds $100,000 in the current or previous calendar year, or if it has a physical presence in the state. Most services are taxable as well as goods.
Do I owe U.S. income tax if my Canadian company sells to South Dakota customers?
Generally not, unless the company has a permanent establishment in the United States under the Canada-U.S. tax treaty. A company relying on the treaty may still need to file a U.S. return disclosing that position.
What is the FBAR threshold?
An FBAR is required when the total value of foreign financial accounts exceeds $10,000 at any time during the year. It is filed on FinCEN Form 114, due April 15 with an automatic extension to October 15.
I'm Canadian and rent out a property in South Dakota. What do I file?
Without an election, 30 percent of gross rent is withheld. Most owners elect to be taxed on net rental income and file a U.S. nonresident return, then report the property and claim foreign tax credits in Canada.
Talk to BOMCAS About Cross-Border Tax in South Dakota
Cross-border clients usually need the U.S. side handled through personal tax preparation or business tax preparation, and Canadian businesses selling into the state often need sales and use tax registration. Companies setting up here typically add bookkeeping and payroll, tax planning covers the timing of a move, and anyone with missed filings can start with back taxes and late filing. For a summary of how South Dakota taxes businesses and residents, see the South Dakota accounting and tax overview or our United States services.
Tell us what you need help with and we will reply with next steps. Contact BOMCAS, use the contact form below, call 780-667-5250 or email info@bomcas.ca. You can also go back to the South Dakota overview. This page is general information, not advice for a particular situation.