International Tax Planning: Key Principles for Globally Mobile Individuals

International tax planning is not a single discipline — it is the intersection of dozens of different countries' tax systems, a complex web of bilateral treaties, and a rapidly evolving set of supranational rules driven by the OECD and the EU. For globally mobile individuals, understanding the foundational principles is the starting point for making sound decisions about where to live, how to structure assets, and when to take income.

This article provides a framework — not a comprehensive tax guide, which would require many volumes — for understanding how international taxation works, what the key concepts mean, and where the opportunities and risks lie.

Tax law is jurisdiction-specific and changes frequently. This article reflects the position as of 2026. Professional advice is essential for all specific decisions.

The Foundation: Where Are You Taxed?

Tax Residence

The starting point for international tax planning is determining your tax residence — the country (or countries) that have the primary right to tax your income, gains, and assets.

Every country has its own rules for determining tax residence. Common tests include:

• Days of presence — the UK Statutory Residence Test uses days spent in the UK as a primary factor; the UAE uses 183 days as a threshold for tax residence purposes
• Domicile — some countries (particularly UK) use domicile (your permanent home jurisdiction) rather than just residence for certain purposes
• Economic ties — Germany and Australia consider factors such as habitual abode, family, and business interests
• Citizenship — the US uniquely taxes on citizenship regardless of residence

A person can, in principle, be tax resident in two countries simultaneously if both countries' rules treat them as resident. Double taxation agreements (DTAs) typically resolve this through tie-breaker provisions — based on permanent home, centre of vital interests, habitual abode, and nationality — to determine a single country of residence for treaty purposes.

Domicile

Domicile is a distinct concept from residence, particularly relevant under UK law. Broadly, your domicile is the country you regard as your permanent home — where you intend to spend the rest of your life, or to which you would return if circumstances allowed.

Domicile is sticky: it is not changed simply by moving abroad. You acquire a "domicile of choice" in another country by establishing permanent residence there with the intention of staying permanently. Following the UK's non-dom reforms on 6 April 2025, domicile has ceased to be the central connecting factor for UK tax. The remittance basis and the non-dom regime were abolished and replaced by the four-year Foreign Income and Gains (FIG) regime for new arrivers, which is based on years of UK residence. Inheritance tax also moved from a domicile basis to a residence basis (a "long-term UK resident" — broadly, UK-resident for 10 of the previous 20 tax years — is within the scope of UK IHT on worldwide assets). The common-law concept of domicile still has some residual relevance, for example in older trust structures and in some double tax treaties, but the "deemed domicile" and "15 of 20 years" rules no longer apply.

Source of Income

Even where a person is non-resident in a country, that country may still tax income arising within its borders. The UK taxes:

• UK rental income earned by non-residents
• UK employment income for work performed in the UK
• UK dividends and interest (subject to treaty relief)
• Capital gains on UK residential property by non-residents

The US taxes non-residents on US-source income — dividends, interest, rent — typically through withholding tax.

Understanding what sources of income you have, and where each source is taxed, is fundamental to international tax planning.

Double Taxation and How It Is Relieved

The Double Taxation Problem

Without any relief, income could be taxed twice: once in the country where it arises (source country) and once in the country where the investor is resident (residence country). For cross-border investors, this would make international investment prohibitively expensive.

Double Taxation Agreements

DTAs are bilateral treaties between countries that allocate taxing rights and provide mechanisms for relief. The OECD Model Tax Convention provides the template that most countries follow (with variations).

A typical DTA will:

• Define tax residence and provide tie-breaker rules
• Allocate taxing rights for different income categories (business profits, dividends, interest, royalties, pensions, employment income, capital gains, etc.)
• Provide either an exemption (the residence country exempts income taxed in the source country) or a tax credit (the residence country taxes the income but credits tax paid abroad)
• Include an anti-abuse clause to prevent treaty shopping

The specific terms vary enormously between treaties. The UK-US DTA is one of the most comprehensive; the UK-UAE DTA is limited. The difference can have significant financial consequences.

Treaty Shopping

Treaty shopping means routing income through a third country to access a more favourable treaty rate. For example, routing dividends from Country A through a holding company in Country B to access Country B's lower treaty withholding rate on dividends from A. Anti-abuse rules (including the Principal Purpose Test in many post-2017 OECD-aligned treaties) have significantly restricted this approach. Structures must have genuine commercial substance.

Unilateral Relief

Where no DTA exists, most countries provide unilateral double taxation relief — a credit against domestic tax for foreign tax paid on the same income. This is less favourable than treaty relief because it may not cover all income types and the mechanics of calculating the credit can be complex.

Key Tax Categories for International Investors

Employment Income

If you work in a country, that country has the right to tax income attributable to that work. Working across borders — common for senior executives and international professionals — creates complex employment tax situations. The OECD model gives the source country taxing rights where an employee is present for more than 183 days in a 12-month period, but there are many exceptions.

UK nationals working abroad should be aware of Overseas Workday Relief (OWR) — available to qualifying new arrivals in the UK and certain foreign employees — which allows a proportion of employment income to be received free of UK tax where it relates to overseas workdays.

Investment Income

Dividends, interest, and rental income each have specific treaty treatment. Key principles:

• Dividends: Source country typically withholds tax at a treaty rate (often 5-15%); residence country may also tax but provides a credit.
• Interest: Often exempt from source-country tax under treaties, particularly for government bonds.
• Rent: Source country (where property is located) typically retains full taxing rights.

Capital Gains

Gains on the sale of property (other than shares) are typically taxed in the country where the property is located. Gains on shares and other investments are generally taxable only in the investor's residence country, unless the shares derive most of their value from property.

For UK non-residents, capital gains on UK residential property are always taxable in the UK (reported through a Non-Resident Capital Gains Tax return). Commercial property gains are also taxable in the UK for non-residents in most cases.

Inheritance and Estate Tax

Unlike income and capital gains, estate taxes are rarely covered by comprehensive DTAs. The UK has estate tax treaties with only a handful of countries (US, France, India, Ireland, Pakistan, South Africa, Sweden — though some of these are outdated). For internationally mobile individuals with assets in multiple jurisdictions, double estate taxation is a genuine and under-addressed risk.

Structures such as trusts, foundations, and life insurance policies can mitigate estate tax exposure, but the interaction between different jurisdictions' estate tax rules must be carefully analysed.

Planning Principles

Pre-Departure Planning

Much of the value in international tax planning comes from decisions made before a move. Key actions to consider before leaving a country:

• Crystallise gains before departure if the destination country has no capital gains tax (or a lower rate) but the departure triggers exit taxes (see our dedicated guide on exit taxation).
• Structure future income sources to be received in the most tax-efficient jurisdiction.
• Review existing structures — trusts, companies, pensions, insurance bonds — for how they interact with the new residence.
• Ensure pension arrangements are optimised — contribution opportunities may be lost on departure.
• Establish investment vehicles (offshore bonds, holding companies) while still resident, if beneficial.

Residence Management

For some individuals with flexibility over where they spend their time, actively managing their residence status can produce significant tax savings. Key points:

• The UK's Statutory Residence Test is a precise test with specific day counts — getting this wrong can be costly.
• Some countries impose residency based on family ties, not just personal presence — a spouse or children remaining in a country can create residency risk.
• Establishing genuine residence requires not just being present but having a real home, social connections, and other indicators of integration.
• "Permanent traveller" strategies — living nomadically to avoid any single country's residency threshold — work in theory but require meticulous record-keeping and careful route planning. They also create substance challenges for any corporate structures.

Income Timing

The tax year in which income is recognised or realised matters. Strategies include:

• Deferring gains until a tax year of lower income (using offshore bonds or similar).
• Accelerating gains before departure to a higher-tax jurisdiction.
• Timing pension withdrawals to coincide with lower-income years.
• Using annual exemptions (CGT annual exemption, gift exemptions) consistently.

Structure Selection

The right structure — trust, company, offshore bond, family investment company — depends on the specific combination of the investor's residence and domicile, the location of assets, the income type, and the succession objectives. There is no universally optimal structure; the best answer is always fact-specific.

Anti-Avoidance Rules: A Framework

International tax planning operates within an increasingly tight anti-avoidance framework. Key rules that globally mobile investors encounter include:

• Controlled Foreign Company (CFC) rules — tax offshore corporate profits to UK shareholders in certain circumstances
• Transfer of Assets Abroad — UK rules that can tax UK-resident individuals on income accruing to offshore companies or trusts they have created
• General Anti-Abuse Rule (GAAR) — UK rule preventing abusive tax arrangements
• BEPS measures — limits on artificial profit shifting, substance requirements, treaty abuse provisions
• Mandatory Disclosure (DAC6/MDR) — reporting requirements for certain cross-border tax planning arrangements

Understanding these rules is as important as understanding the positive planning opportunities. Strategies that appeared compliant before the BEPS project (post-2015) may not withstand scrutiny today.

The Role of Professional Advisers

International tax planning requires a team. A UK tax adviser cannot adequately advise on a structure's implications in Singapore, the UAE, or Switzerland — and vice versa. For any significant cross-border planning, you need:

• A specialist international tax lawyer or tax adviser in each relevant jurisdiction
• A financial adviser with genuine cross-border expertise (not just domestic expertise applied internationally)
• Trustees or company administrators with substance in the relevant offshore jurisdictions
• A coordinating adviser who understands the whole picture and can ensure the team works together

The cost of proper multi-jurisdictional advice is significant, but it is a fraction of the cost of getting it wrong.

How Global Investments Can Help

Global Investments has provided international financial planning advice to globally mobile individuals for over 32 years. We understand the key principles of international tax planning and work alongside specialist tax lawyers and advisers in each relevant jurisdiction to provide coordinated, coherent advice.

We help clients identify planning opportunities, select appropriate structures, manage ongoing compliance, and adapt their arrangements as circumstances change. Whether you are at the outset of a first move abroad or managing complex multi-jurisdictional wealth, contact us to begin the conversation.

Tax rules are complex and jurisdiction-specific. They change frequently. This article is for information and general guidance only. It does not constitute tax, legal, or financial advice. Always take professional advice tailored to your specific circumstances before acting.