27 Jul 2026 · Vietnam VI

Citizenship · Capital · Global Mobility

The Legation Times

Tax residence: what it is and how it is determined

Tax residence: what it is and how it is determined

What is tax residency and how is it determined? This is the concept that determines tax obligations, more important than nationality. Analyze the criteria, risks of dual residence and how to verify.

Fact Table

Verified Claim Source
Participating jurisdictions exchange specified financial-account information under the Common Reporting Standard. 1
Tax residence is determined under domestic law and applicable treaties, not simply by citizenship or a residence permit. 2

What is tax residency in essence

What is tax residency? To be precise, it is a legal status that determines whether a country has the right to tax an individual on his or her income, and to what extent. Most tax systems around the world determine obligations based on tax residence, which means where an individual actually lives and has major economic connections, not based on nationality or passport.

This is a core distinction that many people overlook. A person can hold the citizenship of one country but be a tax resident of another country, and their main tax liability is tied to their tax residence. Correctly understanding what tax residency is helps avoid two false expectations: That changing your passport will change your tax liability, or that wherever you live, you will only pay taxes there.

Criteria for determining tax residency

Determining tax residency is usually based on the number of days of presence in the year, combined with factors such as permanent residence, center of economic interests and family relationships. Many countries use a threshold number of days as a benchmark, but the number of days is not the only factor; Housing, work, and family connections are also considered together.

Specific criteria vary from country to country, so the same situation can lead to different conclusions depending on the system. This is the reason why it is not possible to apply a general formula to all cases, and why determining one's tax residency needs to be based on the criteria of each relevant country instead of guessing.

Risk of double tax residence

A complicated situation is when a person can be considered tax resident in more than one country at the same time — for example, having enough days of presence in one country, while also having a home and family in the other country. At that time, the same income is at risk of being taxed in many places, creating a double burden.

As a treatment, double taxation agreements between countries often provide a series of delimitation criteria to determine the main place of residence. However, the application of these criteria is not automatic and can be complicated, so people in dual residency situations should consult an expert rather than draw their own conclusions.

Tax residency and relocation decision

For those considering moving or obtaining residency in another country, answering what tax residency is is a factor that needs to be considered from the beginning. The actual change in tax liability usually comes from changing tax residence, not from having an additional passport or residence permit while still living in the same place.

The moment of becoming a tax resident of a country is an important boundary: Many asset arrangements, ownership structures or the timing of recording a transfer can only be considered before crossing that boundary. This is why it's a good idea to consult a tax advisor before moving, not after.

Declaration obligations come with tax residency

Tax residency not only determines the tax payable but also entails the obligation to declare. Many countries require their tax residents to declare their overseas accounts and assets, and in the context of increasingly strict automatic exchanges of financial information, these obligations are difficult to avoid.

Omitting a filing obligation, even if it does not result in additional taxes, can still lead to undesirable consequences. Therefore, when identifying yourself as a tax resident of a country, readers should also review the declaration obligations that such status entails, not just the tax portion.

Verification and professional consultation

Because the answer to the question of what is tax residency is different depending on the legal system, people with income or assets spread across many countries should review their tax residency status according to each country's criteria, and find out whether there is a double tax avoidance agreement between the countries and to what extent.

This is a group of issues that should be assessed by a tax advisor with expertise in the relevant countries, rather than speculating from the experience of others. The Legation Times provides background information to ask the right questions, not a substitute for personalized tax advice for each case.

Sources: OECD: Common Reporting Standard · OECD: Tax residency

The Legation Times writes its content from published documents; nothing here is legal, tax or investment advice. Spotted an error? Send a correction request; for content rights, send a takedown request.

← Back to updates

Read next

Emerging-market portfolio capital grew, but exit risk became more concentrated
Tax & Assets

Emerging-market portfolio capital grew, but exit risk became more concentrated

Emerging-market portfolio capital grew, but exit risk became more concentrated Nonbank financial institutions now account for about 80% of emerging-market portfolio debt liabilities. The shift expands funding, while making prices and currencies more sensitive to fund withdrawals.
Global FDI rebounded, but concentration changes what the headline means
Tax & Assets

Global FDI rebounded, but concentration changes what the headline means

Global FDI rebounded, but concentration changes what the headline means UNCTAD and the OECD both report higher foreign direct investment, yet large transactions, intra-company loans and concentration in a small group of economies make the aggregate an inadequate substitute for market-level diligence.
Bulgaria’s proposed stay rule could collide with tax residence
Tax & Assets

Bulgaria’s proposed stay rule could collide with tax residence

Bulgaria’s proposed stay rule could collide with tax residence The measure is not yet effective, but it could alter the value of investment-linked permanent residence by bringing the travel calendar used to retain status close to a separate domestic tax threshold.
Cross-border capital transfers: the evidence chain decides
Tax & Assets

Cross-border capital transfers: the evidence chain decides

Cross-border capital transfers: the evidence chain decides Many investment migration applications stall not for lack of funds but for lack of an unbroken document chain covering how those funds moved. In today's environment of financial information exchange, banks and assessing authorities…
Renouncing citizenship and exit tax: the price often overlooked
Tax & Assets

Renouncing citizenship and exit tax: the price often overlooked

Renouncing citizenship and exit tax: the price often overlooked Renunciation of citizenship can trigger exit taxes and many long-term consequences. Analyze the tax mechanism upon termination of residence or citizenship, principles of not falling into statelessness and what needs to be verified.
How to read country investment-opportunity indices
Tax & Assets

How to read country investment-opportunity indices

How to read country investment-opportunity indices The investment opportunities index by country helps compare the environment between countries, but is only a narrow slice. Analyze what indicators measure, how to read them and their limitations for investors.