Treaty Tie-Breaker Rule: Who Wins When the US and UK Both Claim You

The treaty tie-breaker rule in Article 4 of the UK-US Income Tax Treaty decides which country treats you as its resident when both claim you under domestic law. It applies four tests in order: permanent home and centre of vital interests, habitual abode, nationality, then mutual agreement. A US citizen still files Form 1040 either way, because of the saving clause. A green card holder can use the rule to file as a non-resident.

Dual residence is common. The UK counts you as resident under its Statutory Residence Test. The US counts you as resident if you hold a green card or meet the substantial presence test, and it taxes citizens wherever they live. Therefore, an American in London, or a British green card holder who has moved home, is often resident in both countries at once. This guide explains how the treaty tie-breaker rule resolves that, what it changes, and where it carries a real cost.

How the treaty tie-breaker rule works under Article 4

The rule only starts once both countries treat you as resident under their own law. Article 4(4) of the UK-US Income Tax Treaty, signed in 2001, then applies a strict sequence. You stop at the first test that gives a clear answer. The treaty text is published on GOV.UK in the USA tax treaties collection and by the IRS on its United Kingdom tax treaty documents page.

Permanent home and centre of vital interests

A permanent home is any dwelling you keep available for your own use at all times. A house let to tenants on a long lease is not available to you. If you have a home in only one country, the test ends there. If you have a home in both, or in neither, you move to the centre of vital interests. That weighs family location, employment, business interests, investments and community ties. In practice, where your spouse and children live carries heavy weight.

Habitual abode, nationality and mutual agreement

If your ties are evenly split, the treaty looks at where you habitually live. This is not a simple day count, although days matter. Our guide to the 183-day rule in the UK, US and UAE explains why day counts and treaty residence are different questions. If that fails, nationality decides. A dual national, or a national of neither country, falls to the competent authorities, which is slow and rare.

The special rule for US citizens and green card holders

Article 4(2) adds a condition that many people miss. A US citizen or green card holder counts as a US resident for treaty purposes only if they have a substantial presence, a permanent home or a habitual abode in the United States. Consequently, an American who has lived in the UK for years with no US home is usually not a US treaty resident at all. In that case there is no tie to break: the UK is the only country of treaty residence.

What the tie-breaker changes for each type of taxpayer

The outcome matters far more for some people than for others. The saving clause in Article 1(4) lets the US tax its citizens as if the treaty did not exist, with limited exceptions. It does not apply in the same way to a green card holder who is treaty resident in the UK.

US citizens: a smaller benefit than expected

For a citizen, the treaty tie-breaker rule does not remove the Form 1040. It decides which country is the residence country for treaty purposes. That drives which country gives the credit, how the re-sourcing rules apply, and which saving clause exceptions you can use. Our guide to the saving clause exceptions in the US-UK treaty covers what survives.

Green card holders: a powerful election with a cost

A green card holder who is treaty resident in the UK may file Form 1040-NR and report only US-source income. Under Treasury Regulations section 301.7701(b)-7, you must attach Form 8833, Treaty-Based Return Position Disclosure. Section 6712 of the Internal Revenue Code sets a $1,000 penalty for an individual who fails to disclose. The IRS explains the form on its About Form 8833 page, and our guide to when Form 8833 must be filed walks through it.

The risks of claiming the treaty tie-breaker rule

The claim affects the computation of US income tax only. It does not switch off everything else, and for long-term green card holders it can trigger a far larger charge.

The expatriation trap for long-term residents

A long-term resident is someone who has held a green card in at least 8 of the last 15 tax years. Under section 7701(b)(6) of the Internal Revenue Code, a long-term resident who claims treaty residence in another country, and does not waive the treaty benefit, is treated as having given up US residence. That is an expatriation. If you are a covered expatriate under section 877A, for example because your net worth is $2 million or more, the exit tax applies and Form 8854 is due. Our guide to the US exit tax explains the tests.

Immigration status and information returns

Filing as a non-resident can be used as evidence that you have abandoned your green card. Speak to an immigration lawyer before you file. In addition, the regulations treat you as a US resident for purposes other than computing your own tax. FinCEN's FBAR rules still apply to a green card holder who makes a treaty claim, and reporting for foreign companies can continue. Therefore, the treaty tie-breaker rule reduces tax but not all of the paperwork.

How the UK side works

HMRC applies the same Article 4 tests. If you are UK resident under the Statutory Residence Test but treaty resident in the US, you remain UK resident in law. However, you claim treaty relief in your Self Assessment return, and the UK can then tax only the income the treaty allocates to it. GOV.UK sets out the starting point in its guidance on UK residence and tax. Our UK-US tax treaty page covers the articles that then apply.

An illustrative case

Consider an illustrative British national who held a green card for nine years and moved back to Manchester in March 2026. The figures are illustrative. She sold her Texas home, rents a flat in Manchester and works for a UK employer, but kept her green card. Under US law she is a resident for all of 2026. Under the treaty, her only permanent home is in the UK, so she is treaty resident there from her move. She could file Form 1040-NR with Form 8833 and keep her UK salary out of US tax. However, nine years makes her a long-term resident. The claim would count as expatriation, and with a net worth above $2 million she would face the exit tax. Formally surrendering the card after planning, or filing as a resident with foreign tax credits, may cost less.

If you are resident in both countries, book a consultation before you file. We test the Article 4 position, model both filing routes and check the expatriation rules first.

Frequently Asked Questions

What is the treaty tie-breaker rule?

The treaty tie-breaker rule is the set of tests in Article 4 of the UK-US Income Tax Treaty that assigns a dual resident to one country for treaty purposes. It looks in order at permanent home, centre of vital interests, habitual abode and nationality, and finally at agreement between HMRC and the IRS.

Can a US citizen use the tie-breaker rule to stop filing US tax returns?

No. The saving clause in Article 1(4) of the UK-US Income Tax Treaty lets the United States tax its citizens as if the treaty were not in force. A US citizen who is treaty resident in the UK still files Form 1040 on worldwide income and relieves double tax with foreign tax credits or the Foreign Earned Income Exclusion.

How does a green card holder claim the tie-breaker rule?

A green card holder who is treaty resident in the UK files Form 1040-NR and attaches Form 8833, Treaty-Based Return Position Disclosure, as required by Treasury Regulations section 301.7701(b)-7. A long-term resident, meaning a green card holder in at least 8 of the last 15 tax years, is treated as expatriating when they make the claim.

Do I still file an FBAR if I claim treaty non-residence?

Yes. A green card holder who elects to be taxed as a non-resident under a treaty remains a US person for FinCEN purposes and must still file FinCEN Form 114 if foreign accounts exceed $10,000 in aggregate at any time in the calendar year.

How does HMRC treat someone who is treaty resident in the US?

HMRC still treats the person as UK resident under the Statutory Residence Test, but the UK-US Income Tax Treaty limits what the UK can tax. The individual claims treaty relief in their Self Assessment return, and the UK then taxes mainly UK-source income that the treaty allocates to it.

Is there a tie-breaker rule between the US and the UAE?

No. The United States has no income tax treaty with the United Arab Emirates, so there is no tie-breaker rule to rely on. The UK and the UAE do have a double taxation convention, signed in 2016, and Article 4 of that treaty contains its own tie-breaker tests for UK-UAE dual residents.