Mixed-citizenship couples are common in Canadian cities — particularly Toronto, Vancouver, and Montreal. They're also some of the hardest estate-planning files we see, because the standard US marital deduction is unavailable when the surviving spouse is a non-US citizen, and the alternatives all have substantial trade-offs.
The default US marital deduction
Under IRC section 2056, a US citizen who dies leaving property to a surviving spouse can pass the property to the spouse with a full estate-tax marital deduction — there is no estate tax until the surviving spouse's death (or until the property passes out of the spouse's hands). The deduction is unlimited in amount and applies to most kinds of property.
But subsection 2056(d) takes the deduction away when the surviving spouse is not a US citizen. Congress's worry was that a non-citizen surviving spouse could leave the country with the property, taking the deferred estate tax with them.
The QDOT solution
Section 2056A provides the workaround: a Qualified Domestic Trust (QDOT). If property passes from the deceased US citizen to a QDOT for the benefit of the non-citizen spouse, the marital deduction is allowed. The QDOT defers the estate tax until the surviving spouse takes principal distributions or until the surviving spouse's death.
To qualify as a QDOT, the trust must:
- Have at least one trustee who is either a US citizen or a US corporation (the "US trustee").
- Provide that no distribution of principal can be made unless the US trustee withholds estate tax on the distribution.
- Meet additional security requirements based on the value of the trust (over US$2 million, the trust must hold either a substantial portion of its assets in US property or provide a bond or letter of credit).
- Be expressly designated as a QDOT in the will or election.
What the QDOT actually does
The QDOT defers — does not eliminate — the estate tax. When the surviving spouse takes principal distributions or dies, the deferred tax becomes payable. The non-citizen spouse can take income distributions throughout her lifetime without triggering the tax. Principal distributions for "hardship" (medical, education, support) are excluded from the deferred-tax pool.
The structure is administratively burdensome: a US trustee must be retained, annual filings are required, and principal distributions are tax-events. For couples who intend the survivor to stay in the United States, the QDOT's benefit is real. For couples who intend the survivor to return to Canada after the citizen's death, the QDOT may end up costing more than it saves.
The alternative — pay the tax
For families where the QDOT's administrative burden outweighs the deferral value, an alternative is to use the US citizen's unified credit (currently sheltering ~US$13.6 million) on the bequest to the non-citizen spouse and accept that any excess is currently estate-taxed. This is often the right call where the assets in the bequest are modest relative to the credit, or where the surviving spouse is likely to move and trigger the deferred QDOT tax soon anyway.
The Canadian side
On the Canadian side, the deceased's terminal T1 applies the capital-gains-at-death rule under Section 70(5). For most Canadian-resident couples, the spousal rollover under Section 70(6) defers the Canadian tax to the surviving spouse's hands — the same way the US marital deduction works on the US side. The rollover works for non-citizen spouses (it's a residency-based, not citizenship-based, regime).
The cross-border complication arises when the deceased was a US citizen resident in Canada. The Canadian terminal T1 typically uses the spousal rollover; the US Form 706 typically uses (or doesn't use) the QDOT. The two analyses run in parallel; coordinating them is the work.
Real-world fact patterns
- US-citizen husband, Canadian-citizen wife, all assets in Canada. The US 706 reports the worldwide estate; QDOT planning shelters the bequest to the wife from current US tax. The Canadian T1 uses the spousal rollover. Most assets pass to the wife with both rollovers in place.
- US-citizen husband, Canadian-citizen wife, Florida condo + Canadian assets. Same as above, but with US-situs property layering in. The Florida condo can go into the QDOT or can be retitled before death to avoid US-situs treatment.
- Canadian-citizen husband, US-citizen wife, mixed assets. If husband dies first, US estate tax doesn't apply to his estate (he's not a US citizen and the situs analysis covers only the US assets). If wife dies first, the QDOT issue applies to bequests to him.
The bottom line
Mixed-citizenship estate planning is a coordination problem more than a doctrinal one. The Canadian side and the US side each have well-established tools; getting them to point at the same outcome takes care. The right time to plan is BEFORE the will is drafted, not after.