Most arguments about residence begin with the wrong noun. A founder says, "I live in Portugal." A bank asks for every country of tax residence. A lawyer asks about domicile. An immigration adviser discusses a residence permit. Each may be correct, because each is answering a different question.
For globally mobile people, the useful task is not finding one label that describes an entire life. It is building a small map of the labels that apply, the law behind each one and the evidence that supports the answer.
Five labels that answer different questions
Immigration permission answers whether a person may enter, live or work in a country. A visa or residence card can be important evidence, but it is not a universal tax certificate.
Domestic tax residence answers whether a country's own law treats the person as resident. The test can involve a day count, a home, work, family or a sequence of statutory tests. Two countries can reach "resident" at the same time.
Treaty residence matters when two treaty partners both treat the person as domestically resident. The relevant treaty may use tie-breaker rules to decide which country can treat the person as resident for specified treaty purposes. That does not automatically cancel domestic returns, disclosures or every local-law consequence.
Domicile or an equivalent long-term connecting concept usually looks beyond where someone happens to spend this year. Its meaning varies sharply by legal system and may matter to succession, family law or tax rules outside the current residence analysis.
Financial-account reporting residence is the answer given to banks and other institutions for regimes such as CRS or FATCA. It must be consistent with the facts and with the particular reporting rules, not merely with the most convenient label.
Domestic residence comes before treaty tie-breakers
A treaty tie-breaker is not normally the first test. Each country applies its own domestic rules first. Only where both countries claim residence, and an applicable treaty covers the situation, does the treaty analysis become relevant.
The UK illustrates why headline day counts are unreliable. HMRC's Statutory Residence Test guidance contains automatic overseas tests, automatic UK tests and sufficient-ties rules. A person's result can depend on more than the number shown by an airline app.
The United States uses a different statutory calculation. The IRS substantial presence test generally requires at least 31 days in the current year and a weighted 183-day calculation across three years, subject to exclusions and exceptions. That example is useful because it demonstrates the point: "183 days" can describe a formula, not merely this year's overnight total.
Treaty wording, eligibility and procedural claims also matter. A reader should not assume that being "treaty resident" removes the need to file in the other country or disclose the position to an institution.
Why domicile still appears in legal and estate conversations
Domicile is often used casually to mean home. Legally, it can be a deeper and more persistent connection. Different systems define and use it differently, and some use concepts such as habitual residence, nationality or situs instead.
The UK ended its former non-dom tax regime on 6 April 2025 and moved to residence-based rules for the replacement regime, as reflected in HMRC's current residence guidance. That change did not make the word domicile disappear from every will, succession question, trust document or other country's law.
An international family therefore needs the question stated precisely. "Where am I domiciled?" may be relevant to a lawyer considering succession. It may be the wrong question for an accountant testing this year's income-tax residence.
What banks ask under the Common Reporting Standard
CRS gives the distinction operational consequences. A financial institution can ask an account holder to self-certify every jurisdiction of tax residence and the associated tax identification numbers. A change of address or other circumstance can cause an existing certification to be reviewed.
The OECD's consolidated 2025 CRS text should be read alongside local implementation. The practical point is simple: a bank form is not the place to improvise a treaty conclusion. If domestic rules create two residences, the reporting answer may need both even when a treaty analysis allocates residence for certain tax outcomes.
This is why bank, broker and tax files should tell a coherent story. A Portuguese address, a UK tax return, a US passport and a treaty position may all be legitimate. Unexplained contradictions create avoidable questions.
Build a two-country evidence file
A useful residence file is chronological, not decorative. It can contain:
- a day-by-day travel calendar, with the source of each entry;
- details of homes owned, rented or available in each country;
- workdays, board meetings and where management decisions happened;
- the location of a spouse, partner, children and school terms;
- immigration registrations and dates;
- tax registrations, returns, certificates and correspondence;
- bank and broker self-certifications; and
- advice that records both the facts supplied and the assumptions used.
The file should distinguish confirmed facts from plans. A signed lease is a fact. "We expect to spend most of next year there" is a plan. Residence decisions are often made after the year ends, when memories have softened and plans have been mistaken for events.
Composite scenario: one family, five answers
Consider a British founder who moves with a spouse to Lisbon in September. The founder retains a London flat, attends UK board meetings, holds a US brokerage account and receives a Portuguese residence card. The children start school in Portugal, but the family returns to Britain frequently.
The residence card establishes an immigration position. Portugal and the UK must each apply domestic tax law to the actual year. If both claim residence, the relevant treaty analysis may be needed. The bank may ask for every tax residence under CRS. The family's wills and estate plan may raise separate domicile, habitual-residence, nationality and asset-location questions.
No single document answers all of those questions. The defensible output is a coordinated set of conclusions, each labelled by purpose and each based on the same timeline.
Questions for advisers
- Which domestic residence tests apply in each country, and which facts are still uncertain?
- Could both countries claim residence for the same period?
- If a treaty applies, which benefits and filing obligations does the tie-breaker affect?
- What should be disclosed to banks and brokers under CRS or FATCA?
- Does domicile, habitual residence, nationality or asset situs create a separate succession issue?
- Which conclusion depends on a planned fact that has not happened yet?
For the departure side of this map, read How to Think About Exit Planning Before Leaving the UK. For the banking consequences, see Why Banking Gets Harder as Your Life Gets More International.
FAQ
Can someone be tax resident in two countries at once?
Yes. Domestic rules can make the same person resident in more than one jurisdiction. A treaty may allocate residence for particular treaty purposes, but it does not necessarily erase every domestic filing or reporting obligation.
Does a residence visa make someone tax resident?
Not automatically. A visa grants an immigration right. Tax residence is determined under domestic tax law, which may examine days, homes, work, family ties or other facts.
Does a treaty tie-breaker change what a bank reports under CRS?
Not in every case. CRS self-certification generally asks for all jurisdictions of tax residence under domestic law, so treaty residence and account-reporting treatment must be checked separately.
Content on Wealth Nomad is for general information and education only. It is not financial, investment, legal, tax, immigration, or accounting advice. Rules vary by jurisdiction and personal circumstances. Always speak to qualified advisers before making decisions.
