Citizenship-based taxation is a system in which a country taxes its citizens on their worldwide income regardless of where they live, and only two countries use it: the United States and Eritrea. Every other nation taxes primarily based on residency, meaning your obligations follow where you live rather than which passport you hold. For roughly nine million Americans abroad, that distinction is the entire reason a U.S. tax return still lands in the mailbox years after leaving the country.
The Two Countries That Use It
The United States taxes citizens and green card holders on worldwide income for life. Wages, investment income, rental profits, retirement distributions: all of it gets reported to the IRS regardless of where you earned it or where you live. Hold the passport, owe the return.
Eritrea imposes a flat 2% levy on the income of citizens living abroad. The UN Security Council condemned the practice in 2011, finding that Eritrea used coercive tactics, including threats and extortion through its embassies, to collect from its diaspora.1Committees of the UK Parliament. Written Evidence Submitted by Mr Martin Plaut (TRUK0002) The tax persists despite that condemnation. Unlike the U.S. approach, which applies the full domestic code to citizens abroad, Eritrea’s version is a single-rate diaspora levy without an extensive reporting infrastructure behind it.
Countries Often Listed by Mistake
Mexico, Hungary, and Myanmar sometimes appear on lists of citizenship-based taxation countries, but the reality is more nuanced. Mexico taxes residents on worldwide income, and Mexican citizens who establish tax residency elsewhere are taxed only on Mexican-source income. That’s residency-based taxation. Hungary treats Hungarian citizens as tax residents by default, but carves out dual citizens who don’t have a permanent home in Hungary. Closer to citizenship-based, but not the blanket obligation the U.S. imposes.
If you’re not a U.S. citizen, green card holder, or Eritrean national, your tax obligations almost certainly follow your residency, not your passport.
What the U.S. System Actually Requires
For the 2026 tax year, a single filer under 65 must file a federal return once gross worldwide income reaches $16,100, the amount of the standard deduction.2Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026 Self-employed? The threshold drops to $400 in net self-employment income.3Internal Revenue Service. Publication 501 (2025), Dependents, Standard Deduction, and Filing Information The thresholds apply to worldwide income, not just U.S.-source income.
Citizens and green card holders living abroad get an automatic two-month extension, pushing the calendar-year deadline to June 15. A further four-month extension takes it to October 15.4Internal Revenue Service. U.S. Citizens and Resident Aliens Abroad Automatic Extension of Time to File The extension covers filing, not payment. Interest still accrues on any unpaid balance from the original April date.
FBAR: Foreign Account Reporting
If the combined balance of your foreign financial accounts exceeds $10,000 at any point in the year, you file a Report of Foreign Bank and Financial Accounts (FBAR) with FinCEN.5Financial Crimes Enforcement Network. Report Foreign Bank and Financial Accounts The $10,000 is an aggregate figure. Two accounts holding $6,000 each trigger the requirement even though neither exceeds the threshold on its own.6Internal Revenue Service. Comparison of Form 8938 and FBAR Requirements The FBAR is filed separately from your tax return, through FinCEN’s BSA E-Filing system, with an April 15 deadline and automatic extension to October 15.
FATCA: Form 8938
The Foreign Account Tax Compliance Act layers a second filing on top of the FBAR. Form 8938 is attached to your tax return and reports specified foreign financial assets. For unmarried filers living abroad, the reporting kicks in above $200,000 on the last day of the year or $300,000 at any point during the year. Married filing jointly: $400,000 year-end or $600,000 at any point.7Internal Revenue Service. Do I Need to File Form 8938, Statement of Specified Foreign Financial Assets? Form 8938 covers a broader range of assets than the FBAR, including foreign securities and interests in foreign entities.
Reducing the U.S. Bill From Abroad
Citizenship-based taxation sounds like a recipe for paying twice, once locally and once to the IRS. In practice, most Americans abroad owe little or no U.S. tax because of two main relief provisions. Both only help if you file. Skipping the return doesn’t cancel the obligation, it just adds penalties.
Foreign Earned Income Exclusion
The Foreign Earned Income Exclusion (FEIE) lets you exclude up to $132,900 of foreign earned income from U.S. tax for the 2026 tax year.8Internal Revenue Service. Figuring the Foreign Earned Income Exclusion To qualify, you have to pass one of two tests:
- Bona Fide Residence Test: you’ve established genuine residency in a foreign country for a period that includes an entire tax year.
- Physical Presence Test: you’ve been physically present in a foreign country for at least 330 full days during any 12-month period.9Internal Revenue Service. 2025 Instructions for Form 2555
Only earned income qualifies: wages, salaries, self-employment income. Investment income, dividends, capital gains, and rental income cannot be excluded. You claim the exclusion by filing Form 2555 with your return.
A related Foreign Housing Exclusion lets you exclude qualifying housing costs above a base amount, up to $39,870 for 2026, with higher caps published for expensive cities like London, Hong Kong, and Tokyo.8Internal Revenue Service. Figuring the Foreign Earned Income Exclusion It’s claimed on the same Form 2555.
Foreign Tax Credit
The Foreign Tax Credit (FTC) reduces your U.S. bill dollar-for-dollar by the income tax you paid to a foreign government. There’s no fixed dollar cap, but the credit can’t exceed the U.S. tax attributable to your foreign income. Pay more foreign tax than you owe the IRS on that income? You can carry the excess back one year or forward for up to ten.10eCFR. 26 CFR 1.904-2 – Carryback and Carryover of Unused Foreign Tax You claim it on Form 1116.
For Americans in higher-tax countries, the FTC is often the better tool. It captures the full foreign tax paid rather than capping the benefit at the FEIE amount.
You Can’t Stack Them on the Same Dollars
You can use the FEIE and the FTC in the same year, but not on the same income. Claiming an FTC on income you already excluded under Form 2555 causes the IRS to treat your FEIE election as revoked.11Internal Revenue Service. Choosing the Foreign Earned Income Exclusion The FTC can still apply to income above the exclusion. Earn $180,000, exclude $132,900, and the credit can go against foreign tax paid on the remaining $47,100.
Treaties and Totalization Agreements
The U.S. has income tax treaties with dozens of countries, but most contain a “savings clause” that preserves America’s right to tax its own citizens as if the treaty didn’t exist.12Internal Revenue Service. Tax Treaties Can Affect Your Income Tax Some treaties carve out narrow exceptions for certain pensions, social security benefits, or student income, but as a rule, don’t expect a treaty to override your filing obligations.
Social Security is handled separately. The U.S. maintains totalization agreements with 30 countries that prevent double social security taxation. If you’re working in a covered country, you generally pay into only one system rather than both.13Social Security Administration. U.S. International Social Security Agreements The list includes most of Western Europe, Canada, Australia, Japan, South Korea, and Brazil. Working in a country without an agreement can leave you paying into both systems at once.
Penalties for Not Filing
The IRS treats foreign reporting obligations seriously, and the penalties reflect that. Failing to file an FBAR carries a penalty of up to $16,536 per violation for non-willful failures, meaning you didn’t know or made an honest mistake.14Federal Register. Inflation Adjustment of Civil Monetary Penalties Willful failures jump to 50% of the account’s highest balance during the year, or $100,000, whichever is greater. Both figures adjust for inflation.
Failing to file Form 8938 triggers a $10,000 penalty, with up to $50,000 more if you don’t file after IRS notice. Any tax understatement tied to undisclosed foreign assets faces a 40% accuracy penalty.15Internal Revenue Service. Summary of FATCA Reporting for U.S. Taxpayers Reasonable cause can waive the penalty, but “I didn’t know” is a harder argument than it once was.
Streamlined Filing for Non-Willful Taxpayers
If you’ve fallen behind and the failure wasn’t intentional, the IRS Streamlined Foreign Offshore Procedures offer a way back. You must have been physically outside the U.S. for at least 330 days in at least one of the three most recent tax years, and your non-compliance must be non-willful: negligence, inadvertence, or a good-faith misunderstanding.16Internal Revenue Service. U.S. Taxpayers Residing Outside the United States You file three years of delinquent returns and six years of FBARs, and the IRS waives all penalties. For expats who are behind, this is generally the best option available.
Accidental Americans
An accidental American is someone who acquired U.S. citizenship automatically, often by being born in the U.S. to foreign parents who left shortly after, or by being born abroad to a U.S. citizen parent, but who has never lived in the country or thought of themselves as American. They owe the IRS annual returns and foreign account reports all the same.
The consequences reach past paperwork. FATCA requires foreign banks worldwide to report accounts held by U.S. persons to the IRS, and non-compliant banks face severe penalties. Many institutions in Europe and elsewhere respond by refusing to open accounts for anyone with U.S. ties, or by closing existing ones. Accidental Americans have faced mortgage rejections, frozen business accounts, and demands from local banks for U.S. Social Security numbers they’ve never had.
Dual citizens who know their status face a milder version of the same problem. FEIE, FTC, and treaty provisions usually eliminate any actual U.S. tax owed. The filing obligations remain, and the interaction between two systems can get complicated around retirement accounts, local tax-advantaged savings, and investment income that doesn’t map onto U.S. categories.
Renouncing and the Exit Tax
For some, lifelong compliance becomes untenable, and renunciation is the only permanent exit. The State Department fee dropped to $450 effective April 13, 2026, down from $2,350.17Federal Register. Schedule of Fees for Consular Services – Fee for Administrative Processing of Request for Certificate of Loss of Nationality of the United States The government fee is the easy part.
The IRS imposes an exit tax on “covered expatriates,” which sweeps in most people with meaningful assets. You’re a covered expatriate if any of the following apply:
- Your net worth is $2 million or more on the date you expatriate.18Office of the Law Revision Counsel. 26 U.S. Code 877 – Expatriation to Avoid Tax
- Your average annual federal income tax over the five preceding years exceeds $211,000 for 2026.
- You can’t certify full federal tax compliance for the five preceding years.
If you qualify, the IRS treats all your assets as sold the day before expatriation. Gain above an exclusion amount ($890,000 for 2025, adjusted annually) is taxed at ordinary capital gains rates.19Internal Revenue Service. Expatriation Tax Deferred compensation and certain retirement accounts follow separate rules. The exit tax is reported on Form 8854, filed with the final dual-status return.20Office of the Law Revision Counsel. 26 U.S. Code 877A – Tax Responsibilities of Expatriation
Renunciation is essentially irreversible, and it removes your right to live and work in the U.S. without a visa. For people holding appreciated real estate, stock options, or large retirement accounts, the one-time exit tax can exceed decades of annual compliance costs. Model it before you file the paperwork.