International Tax Basics: How US Citizens Are Taxed Abroad

The US Taxes Citizens Everywhere on Earth

Only two countries in the world tax their citizens based on citizenship rather than residency: the United States and Eritrea. Every other developed nation taxes based on where you live. This means an American working in Germany, Singapore, or Australia owes US taxes on worldwide income — even if they haven't set foot in the US in a decade. Understanding the rules governing international income is essential for the estimated 9 million Americans living abroad and any US resident with foreign financial assets.

The Foundational Principle: Worldwide Income

US citizens and permanent residents (green card holders) must report worldwide income to the IRS, regardless of where they live or where the income is earned. This obligation persists unless citizenship is formally renounced — a process with its own tax consequences, including an exit tax on unrealized gains above certain thresholds for covered expatriates.

The key filing obligation:

US citizens abroad: Must file Form 1040 if income exceeds the standard deduction threshold ($14,600 single, $29,200 married filing jointly for 2024)
Foreign nationals in the US: File based on residency status under the substantial presence test or green card test
Non-resident aliens: File Form 1040-NR; taxed only on US-source income

Mechanisms That Prevent Double Taxation

The US system includes several mechanisms to prevent Americans from paying full taxes twice — once to the foreign country and once to the US.

Foreign Tax Credit (FTC)

The most commonly used mechanism. Dollar-for-dollar credit against US tax for income taxes paid to foreign governments on foreign-source income. If you earn $100,000 in Germany and pay $30,000 in German taxes, you can apply up to $30,000 as a credit against your US tax liability on that income. Limitations apply based on the foreign income's category (passive, general, and others).

Foreign Earned Income Exclusion (FEIE)

Allows qualifying Americans abroad to exclude a portion of foreign earned income from US taxation. For 2024, the exclusion is $126,500 per person. Qualification requires either the bona fide residence test (residing in a foreign country for an entire tax year) or the physical presence test (spending 330 of any 365 consecutive days outside the US).

FEIE covers earned income only (wages, self-employment) — not passive income like dividends, rent, or capital gains
The housing exclusion allows an additional deduction for qualifying foreign housing costs above a base amount
Choosing FEIE versus FTC depends on the effective foreign tax rate compared to US rates

Key Reporting Requirements

Form	Purpose	Threshold	Penalty for Non-Filing
FBAR (FinCEN 114)	Report foreign financial accounts	Aggregate value exceeds $10,000 at any point in the year	Up to $10,000 per violation (non-willful); up to $100,000+ or criminal charges (willful)
Form 8938 (FATCA)	Report specified foreign financial assets	$50,000 single ($100,000 MFJ) at year-end, or $75,000/$150,000 at any point	$10,000 per failure + up to $50,000 continued failure penalty
Form 2555	Claim Foreign Earned Income Exclusion	N/A (election form)	Loss of exclusion election
Form 1116	Claim Foreign Tax Credit	N/A (election form)	Loss of credit
Form 5471	US shareholders of foreign corporations	10%+ ownership of a controlled foreign corporation	$10,000 per failure

Tax Treaties: Bilateral Agreements

The US has tax treaties with over 65 countries. Treaties serve three main purposes: defining which country has primary taxing rights over specific income, reducing or eliminating withholding tax rates on dividends and interest, and providing tie-breaker rules for dual-resident individuals.

Important: treaties don't eliminate the US filing obligation. They modify the tax result for specific income types. A US citizen in France may be exempt from French tax on certain retirement distributions under treaty provisions — but still must report that income to the IRS.

Passive Foreign Investment Companies (PFICs)

Americans owning foreign mutual funds, ETFs, or certain foreign companies face a punitive tax regime called the PFIC rules. Foreign investment funds that would be classified as investment companies if organized in the US are PFICs. Gains from PFICs face interest charges and can be taxed at the highest marginal rate regardless of holding period — eliminating the preferential long-term capital gains rate. This is a major reason why Americans abroad often avoid locally-sold investment funds.

Controlled Foreign Corporations (CFCs)

US persons owning 10%+ of a foreign corporation must file Form 5471 and may be required to include certain undistributed profits in US taxable income under Subpart F rules or GILTI (Global Intangible Low-Taxed Income) provisions enacted in 2017. These rules were designed to prevent US multinationals from parking profits in low-tax jurisdictions but affect many smaller business owners operating abroad as well.

Disclaimer: International tax law is exceptionally complex and penalties for non-compliance can be severe. This article provides general educational information only. Consult a qualified international tax attorney or CPA for guidance on your specific situation.