Married couples in the U.S. where both spouses are citizens enjoy a major estate tax perk: the unlimited marital deduction. This lets one spouse leave any amount to the surviving spouse free of federal estate tax. But when the surviving spouse is not a U.S. citizen, that deduction does not apply. Without the right planning, a family could face a large tax bill at the first death.
Why the Rule Exists
The IRS has a simple concern. If a non-citizen spouse inherits a large estate tax-free, they could leave the country. The government may never collect the tax. The qualified domestic trust rule under IRC Section 2056A keeps the assets within U.S. tax reach.
The estate tax return must be filed within nine months of death. Without a QDOT in place, the full marital deduction is denied. That can mean the estate owes hundreds of thousands of dollars in federal estate tax right away.
How a QDOT Works
A qualified domestic trust, called a QDOT, is an irrevocable trust built for this exact case. It must meet strict IRS rules:
- At least one trustee must be a U.S. citizen or a U.S. domestic company.
- If the trust holds more than $2 million, it must meet extra safety rules. This may mean posting a bond or using a U.S. bank as trustee.
- The trust papers must include language to make sure estate tax will be held back on payouts of principal.
Income from the trust can generally go to the surviving spouse without triggering estate tax. Payouts of trust principal are subject to estate tax. The rate is the same that would have applied when the first spouse died. When the surviving spouse passes away, any remaining trust assets are also subject to estate tax.
This setup makes sure assets do not leave the country without the federal estate tax being paid.
The Annual Gift Option and Lifetime Gifts
There is another tool that can cut the amount flowing through a QDOT. The yearly exclusion for lifetime gifts to a non-citizen spouse is much higher than the standard gift tax exclusion. For 2026, this amount is $194,000 under IRC Section 2523(i). The standard yearly exclusion for gifts to any other person is $19,000 under IRC Section 2503(b). Both figures are published each year by the IRS in its inflation adjustment notices.
Using this higher exclusion during your lifetime can move a lot of wealth to your spouse over time. This shrinks the estate that passes through the QDOT. It helps your family keep more of what you built together.
Estate Tax Exemption and Global Estate Planning
Families with a non-citizen spouse should also learn how the estate tax exemption applies. In 2026, the federal estate tax exemption is expected to drop when the current rules sunset. For a spouse who lives here for tax purposes but is not a citizen, the QDOT is the main way to keep the marital deduction.
Global estate planning often means lining up U.S. tax duties with the laws of the non-citizen spouse's home country. This includes any tax treaties that apply.
If the non-citizen spouse later becomes a U.S. citizen, the QDOT may no longer be needed. Assets can then be given outright. The full marital deduction applies. But that choice should be made with help from an estate planning team.
What Happens Without a QDOT
Without a QDOT, the full marital deduction is denied. This happens if the first spouse leaves assets straight to a non-citizen surviving spouse. The assets are included in the taxable estate right away. The estate tax is due within nine months. For a large estate, the tax bill can reach into the millions.
Avoiding federal estate tax is possible for these couples. But only with proper planning done in advance. A QDOT can be set up during life as part of a full living trust plan. In some cases, the surviving spouse can create one after the first spouse's death. But strict deadlines apply. Planning ahead is always the safer path.