CANADIAN SNOWBIRD TAX SERIES · PART 4
This article is general educational information about the Canada-US tax treaty and US estate tax. It is not tax, legal, or investment advice. The relief described below is not automatic, must be claimed on a timely-filed US return, and requires disclosures most families do not expect. Estate matters are fact-specific and the consequences of getting them wrong fall on people who cannot correct them. Confirm your situation with a cross-border advisor and estate counsel qualified in both countries.
By Lucas Wennersten, CFP® (US & Canada), CFA · 12-minute read
The relief is generous. The price is telling the IRS what you own everywhere.
A Canadian who dies owning US property faces a US estate tax exemption of US$60,000 on their US-situs assets. That figure has not moved in decades, and against an Arizona condo it is close to meaningless.
Article XXIX-B of the Canada-United States Tax Convention exists to fix that, and for most snowbirds it fixes it completely. Applied properly, the treaty replaces that US$60,000 with a proportional share of the full exemption a US citizen receives — a share that, for the ordinary Canadian family, is usually far larger than the US property is worth.
There are two catches, and they are the reason this post exists.
The first is that the relief is claimed, not granted. It is asserted on a US estate tax return that an executor has to know is required. No return, no relief, and the default is the US$60,000.
The second is the price. To calculate a proportional share, the IRS needs to know the denominator — which means disclosing the value of the entire worldwide estate, including everything in Canada that the US would otherwise never see. Families find this genuinely unwelcome, and it is the single most common reason the relief goes unclaimed by people who plainly qualified for it.
This post covers how the pro-ration actually works, the marital credit that can double it, the small-estate provision almost nobody knows about, what the disclosure really involves, and where the relief runs out. For the wider picture, start with The Canadian Snowbird Tax Guide.
The pro-rated unified credit: the core mechanic
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A US citizen’s estate, filing IRS Form 706, gets a unified credit that shelters a large amount from estate tax. A nonresident alien does not — they get the credit equivalent of a US$60,000 exemption and nothing more.
Article XXIX-B changes the calculation. Instead of the flat nonresident credit, a Canadian estate may claim the greater of:
- the ordinary nonresident credit (the US$60,000-equivalent), or
- the full US unified credit multiplied by the ratio of US-situs assets to the worldwide gross estate
That ratio is the whole idea. If your US property represents 15% of everything you own, you get 15% of the exemption a US citizen would receive.
Read that again, because the arithmetic is more favourable than it first sounds. The exemption available to a US person is measured in millions. A modest fraction of a large number is still a large number — and it is being applied against US-situs assets that, by definition, represent that same modest fraction of your estate. The formula is close to self-balancing. For most Canadian families holding one US property, the pro-rated credit exceeds the value of the property comfortably, and the US estate tax comes out at zero.
This is why the treaty matters more than the headline US$60,000 figure suggests. The scary number is real, but it is the number that applies when nobody claims the relief.
Where the pro-ration stops helping
The formula is self-balancing for ordinary estates. It is not self-balancing at the top.
Consider a Canadian whose US holdings are a substantial share of a large estate — a family with significant US real estate and US equities alongside their Canadian assets. Their ratio is high, so their share of the credit is high. But the US-situs exposure is high too, in absolute dollars, and above a certain scale the credit stops covering it.
The people who actually owe US estate tax after treaty relief are, broadly, those with large estates and a large US share of them. That is a real planning population, and it is where the structural options — holding companies, trusts, life insurance funding — start earning their complexity. Those trade-offs are covered in Holding U.S. Property Through a Holdco.
For the snowbird with one condo and a Canadian life, the pro-ration almost always does the job.
The marital credit: the provision that can double it
Article XXIX-B also provides a marital credit for property passing to a surviving spouse. In broad terms it can add a second credit roughly equal to the first, which for many estates doubles the shelter available.
This exists because of a quirk that catches mixed-nationality families hard. The unlimited marital deduction that lets one US spouse leave everything to another tax-free is not available where the surviving spouse is not a US citizen. The usual workaround is a qualified domestic trust — a QDOT — which is expensive to establish, ongoing to administer, and unwelcome to most families.
The treaty marital credit is the alternative. It is claimed by election, and the election generally requires waiving the QDOT benefits. That is a real decision with real trade-offs, not a formality, and it needs to be made with counsel rather than checked off.
Where one spouse is a US citizen and the other is not, the analysis becomes more involved than this post can carry — that situation is its own subject.
The small-estate provision hardly anyone mentions
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There is a further provision in Article XXIX-B that rarely appears in general coverage and that resolves a lot of cases outright.
Where the worldwide gross estate falls at or below a threshold set in the treaty, US estate tax is limited to US real property and certain business property — meaning US shares and similar US-situs financial assets fall outside the US taxing right entirely.
That is a meaningful result for a specific and common profile: a Canadian of modest overall wealth who holds US stocks in a brokerage account and owns no US real estate. Without the treaty, those shares are US-situs and exposed above US$60,000. With this provision, they may not be taxable in the US at all.
The threshold is a fixed figure written into the treaty rather than an annually indexed one, but confirm the current amount and its application with a cross-border advisor before relying on it. It is exactly the sort of number that matters enormously in a specific case and that should never be taken from a blog post — including this one.
The disclosure: what claiming actually costs
Here is the tension that decides more cases than the arithmetic does.
The pro-rated credit is a fraction whose denominator is the worldwide gross estate. You cannot claim a fraction without establishing both halves of it. So claiming treaty relief means reporting to the IRS the value of everything the deceased owned — the house in Ontario, the RRSPs and RRIFs, the cottage, the private company shares, the Canadian portfolio.
None of that is taxable by the United States. It is disclosed solely to compute a ratio.
Families consistently underestimate how much they will dislike this, and executors are often the ones who discover it. The reaction is understandable: a US filing obligation triggered by a condo, requiring a full accounting of a Canadian family’s wealth to a foreign tax authority.
The trade-off is nonetheless usually one-sided. The disclosure is an information cost. The alternative is a tax cost, and on a US$700,000 property with only US$60,000 exempt, the tax cost is not small. Choosing privacy over the claim is choosing to pay for it.
What deserves saying plainly: this is the point at which the relief and the family’s instincts work against each other. The better the relief, the more it needs to know. Recognising that in advance — and telling your executor it is coming — is most of what separates a smooth filing from a panicked one.
Both countries tax the same death, and the treaty coordinates that too
Canada has no estate tax. What it has is a deemed disposition at death: the Canada Revenue Agency treats capital property as sold at fair market value immediately before death, and the resulting capital gain is taxed on the final return.
So a Canadian dying with a US condo can face US estate tax on its value and Canadian tax on its gain — two different taxes, two countries, one asset, one death.
Article XXIX-B addresses this as well, permitting relief on the Canadian side for US estate tax paid, so the same property is not fully taxed twice. The mechanics are technical and belong with a preparer, but the principle is worth knowing: double taxation here is a solved problem, provided both sides are claimed correctly and in the right order.
The interaction between deemed disposition and US estate tax is covered in more depth in our post on Canadian deemed disposition vs. U.S. estate and gift tax.
How the relief is actually claimed
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Treaty relief is asserted on IRS Form 706-NA, the US estate tax return for a nonresident who is not a US citizen, with a treaty-based position disclosure on IRS Form 8833 attached.
Three points that determine whether it works:
- The return has to be filed, and filed on time. Relief claimed on a late return is at the discretion of the IRS. Relief never claimed does not exist.
- The filing threshold is the US$60,000, not the treaty-relieved figure. This catches people constantly. An estate whose US-situs assets exceed US$60,000 generally has a filing obligation even though the treaty may reduce the tax to nothing. Owing zero and filing nothing are different things.
- The executor is the one who must know. A Canadian executor administering a Canadian estate has no particular reason to suspect a US filing requirement exists. That gap is the failure mode.
The mechanics of the return itself, including its deadline and the extension available, are covered in Form 706-NA for Canadians. Every form named here is in our cross-border tax forms hub.
A worked example: the same condo, two families
Both own a US$700,000 place in Scottsdale. Both are Canadian residents, neither is a US citizen. Both die this year.
The Bergerons have a worldwide estate of roughly CA$4.5 million — the Ontario house, RRIFs, a portfolio, and the condo. The US property is a meaningful but minority share of what they own. Their ratio produces a pro-rated credit that shelters a multiple of the condo’s value. Their executor files Form 706-NA, discloses the worldwide estate, claims the treaty position, and the US estate tax is nil. The cost was an accountant’s fee and a disclosure the family found uncomfortable.
The Lalondes have essentially the same condo and a much smaller Canadian estate — they rent in Montreal and the Scottsdale property is the bulk of their net worth. Counterintuitively, their higher US-situs ratio gives them a larger share of the credit, not a smaller one. They are also candidates for the small-estate provision. Their outcome is likely nil as well, by a different route.
Neither family’s executor knew a US return was required. In one case a Canadian estate lawyer raised it. In the other, nobody did, and the discovery came late enough that the filing was late.
The variable that decided the outcome was not wealth, or the ratio, or the treaty. It was whether somebody knew the obligation existed.
A sequencing checklist for the executor
- Identify every US-situs asset. Real property, US-incorporated shares wherever the account is held, tangible property in the US. If the total exceeds US$60,000, assume a filing obligation until advised otherwise.
- Do not assume zero tax means zero filing. The threshold that triggers the return is not the threshold that triggers the tax.
- Value the worldwide gross estate. This is the denominator, and it is required whether or not the family likes it.
- Determine whether the marital credit applies and whether the election is appropriate. It involves waiving QDOT benefits — that is a decision, not a checkbox.
- Check the small-estate provision. If the worldwide estate is modest and the US assets are financial rather than real property, the answer may be simpler than expected.
- Coordinate with the Canadian final return. Deemed disposition and US estate tax interact, and the order matters.
- File on time. Relief on a late return is discretionary.
- Engage cross-border counsel early. Estate deadlines run from the date of death, and that clock does not pause while a family works out who to call.
Steps 2 and 8 are where the avoidable damage happens.
Five mistakes we see most
- Assuming the treaty applies automatically. It is claimed on a filed return with a treaty position. Silence gets you the US$60,000.
- Believing no tax owing means no return required. The filing trigger is the US$60,000 in US-situs assets, not the amount of tax after relief.
- Not warning the executor. The person who has to act is usually the person least likely to know the obligation exists.
- Refusing the worldwide disclosure without pricing the alternative. The disclosure is an information cost; the alternative is a tax cost, and it is generally much larger.
- Treating US shares in a Canadian account as Canadian. For situs purposes what matters is where the issuer is incorporated, not where the account is held.
Frequently asked questions
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What is Article XXIX-B?
It is the provision of the Canada-US tax treaty that gives Canadian estates access to relief from US estate tax on US-situs assets — principally a pro-rated share of the unified credit available to US citizens, plus a marital credit and a small-estate provision. It must be claimed on a US estate tax return.
How is the pro-rated unified credit calculated?
It is the full US unified credit multiplied by the ratio of US-situs assets to the worldwide gross estate. If your US property is 15% of everything you own, you claim 15% of the credit. A Canadian estate claims the greater of this amount and the ordinary nonresident credit.
Does claiming treaty relief mean disclosing my whole estate to the IRS?
Effectively yes. The pro-ration is a ratio, and the worldwide gross estate is its denominator, so it must be established and reported — including Canadian assets the US has no right to tax. It is disclosed to compute the fraction, not because it is taxable.
Do I have to file a US estate tax return if the treaty reduces my tax to zero?
Generally yes. The filing obligation is triggered by US-situs assets exceeding US$60,000, not by the amount of tax remaining after relief. Owing nothing and filing nothing are different things, and the relief is only available on a filed return.
What is the marital credit?
An additional credit under Article XXIX-B for property passing to a surviving spouse, which for many estates roughly doubles the shelter available. It is claimed by election and generally requires waiving qualified domestic trust benefits, so it should be evaluated with counsel rather than assumed.
Is there relief for smaller estates?
Yes. Article XXIX-B contains a provision limiting US taxation to US real property and certain business property where the worldwide gross estate falls at or below a treaty threshold. A Canadian of modest overall wealth holding US shares but no US real estate may fall outside US estate tax entirely. Confirm the current threshold with an advisor.
Does Canada tax the same property at death?
Canada has no estate tax, but it deems capital property disposed of at fair market value immediately before death, taxing the resulting gain on the final return. So the same US property can attract US tax on value and Canadian tax on gain. The treaty coordinates the two so the property is not fully taxed twice.
What if my spouse is a US citizen and I am not?
The analysis changes materially, because the unlimited marital deduction and the QDOT rules enter the picture alongside the treaty credits. Mixed-citizenship couples should treat this as its own planning exercise rather than applying general guidance.
Are US shares held in a Canadian brokerage account US-situs?
Generally yes. For US estate tax purposes what matters is where the issuing corporation is incorporated, not where the account or the custodian sits. A US stock in a Canadian account is US-situs; a US bank deposit generally is not.
When does the treaty relief run out?
The pro-ration is close to self-balancing for ordinary estates, because a small share of a large exemption is still large relative to a small US holding. It stops covering the exposure for estates that are both large and heavily weighted toward US assets — which is where structural planning starts to earn its complexity.
Who is responsible for claiming this?
The executor of the estate. That is the practical problem: a Canadian executor administering a Canadian estate has little reason to suspect a US filing obligation exists. Telling your executor in advance is the single cheapest thing you can do about it.
More from the Canadian Snowbird Tax Series
- The Canadian Snowbird Tax Guide — the pillar: residency, estate exposure, reporting, healthcare
- Form 8840 & the Closer Connection Exception — staying a nonresident while wintering south
- Form 706-NA for Canadians — the return itself, and its deadline
- Holding U.S. Property Through a Holdco — structures, and what they cost you
- Snowbird Healthcare Coverage — the provincial clock, province by province
For the high-net-worth framing of the same subject, see what the current US estate tax law means for high-net-worth Canadians.
Treaty relief under Article XXIX-B is one of the most valuable provisions available to a Canadian family with US property, and one of the most frequently missed — not because it is hard to qualify for, but because the person who has to claim it is usually the person who never knew it existed. Our cross-border estate planning work starts by finding out whether your executor would know.
If you own US property and have never had the estate side modelled, that is worth an afternoon now rather than a crisis for someone else later. Book a complimentary consultation and we will map your US-situs exposure, run the pro-ration, and tell you plainly whether the treaty solves it or whether you need structure.
