Tax
Worldwide Taxation
Also known as: Worldwide Tax System, Residence-Based Taxation
Worldwide taxation (sometimes "residence-based taxation") is the dominant model among developed economies. A tax resident pays tax on all income — wherever earned, sourced, paid, or held — to the country of residence. Non-residents are taxed only on country-source income (a territorial overlay for the non-resident slice of the population).
The US is the structural outlier in two ways:
• Citizenship-based taxation — the US taxes its citizens and lawful permanent residents (green-card holders) on worldwide income regardless of where they live. Even a US citizen who has never set foot in the US since age 1 ("accidental American") is technically a US tax resident for life until they renounce citizenship through the Department of State and pay the expatriation tax under § 877A. Eritrea is the only other country with citizenship-based taxation. France and the Philippines have residence-based systems but with extensive carve-outs that approximate citizenship-based for some categories.
• Long-arm enforcement — FATCA (foreign banks must report US-person accounts to the IRS) and FBAR (US persons must report foreign accounts to FinCEN) make US worldwide-citizenship taxation enforceable in a way no other country attempts.
Non-US worldwide-taxation countries (UK, Germany, France, etc.) tax residents on worldwide income but exempt that obligation when the individual ceases to be tax resident. The UK, having abolished the non-domiciled regime from April 2025, now operates a relatively pure residence-based worldwide system. Germany's worldwide taxation hinges on tax residency (typically 183-day or place-of-abode tests) — once you're not a German tax resident, German tax obligation reverts to German-source-only.
Practical implications for expats:
• A US citizen can never "escape" US tax by moving abroad. FEIE and FTC mitigate but don't eliminate the obligation. The only full escape is renunciation, which carries an exit tax for high-net-worth or high-income renunciants.
• A UK or German national can fully exit their worldwide-taxation obligation by ceasing to be tax resident. Day-counting and centre-of-vital-interests tests govern this. Many Brits and Germans reduce their tax exposure simply by spending less than the residency-trigger days in their home country and establishing residency in a more favourable jurisdiction.
• Dual citizens (e.g., German-American) face the worst-of-both: US worldwide taxation by citizenship + German worldwide taxation by residence if they remain in Germany. The relief is the US-Germany treaty plus US FEIE/FTC, but the structural complexity is permanent.
Sources
Last factual review: 2026-05-08.
Related terms
Territorial Taxation
Territorial taxation is a system in which a country taxes only income earned within its own borders (or with a domestic source), exempting foreign-source income for residents. Notable adopters in 2026 include Singapore, Hong Kong, Malaysia, Panama, Costa Rica, Georgia, Paraguay, and Thailand. The opposite of worldwide taxation. Most territorial systems still tax foreign income that's remitted to the country, with various carve-outs.
Tax Residency
Tax residency determines which country has primary right to tax your worldwide income. Each country sets its own tests — typically based on physical presence (often 183+ days/year), domicile, primary economic interests, or family ties. Holding a residence permit does not automatically establish tax residency, and tax residency does not require a residence permit. Dual tax residency is resolved by tax-treaty tie-breaker rules.
FEIE (Foreign Earned Income Exclusion)
FEIE lets US citizens and resident aliens exclude up to $132,900 (2026) of foreign-earned income from US federal income tax — but not from Social Security/self-employment tax. To qualify, the taxpayer must meet either the Bona Fide Residence Test (full-year tax residence in a foreign country) or the Physical Presence Test (330 full days abroad in any 12-month period). Claimed on IRS Form 2555 attached to Form 1040.
Double Taxation
Double taxation occurs when the same income or capital is taxed twice — typically once by the source country (where the income arises) and once by the residence country (where the recipient is tax resident). It's prevented by tax treaties (which allocate taxing rights) and by domestic relief mechanisms like the foreign tax credit and the foreign earned income exclusion. Unrelieved double taxation is rare in modern tax systems but can still occur with non-treaty-partner countries.