Citizenship-Based Taxation

Updated on April 13, 2026

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Citizenship-based taxation: what it means for US expats in 2026

Citizenship-based taxation means US citizens must report and potentially pay tax on worldwide income, even while living abroad. Unlike most countries, the US taxes based on citizenship rather than residency, which creates ongoing filing obligations for Americans overseas.

The key point is this: moving abroad does not end your US tax obligations. It changes how they apply, often requiring additional reporting and careful use of tax relief provisions.

Key facts about citizenship-based taxation

Here’s a quick snapshot of how the system works:

Applies primarily to US citizens worldwide
Covers worldwide income, not just US-based earnings
Filing depends on IRS income thresholds and reporting rules
May involve additional reporting (foreign accounts and assets)
Relief exists, but it needs to be applied correctly

This gives you a baseline. From here, it helps to compare the US system with how most countries operate.

Citizenship-based vs residency-based taxation

To make this easier to understand, it helps to compare citizenship-based taxation directly with the system most countries use.

Citizenship-based vs residency-based taxation: key differences

Feature	Citizenship-based taxation	Residency-based taxation
Who is taxed	Citizens worldwide	Residents only
Countries	US (primary example), Eritrea is often cited	Most countries
Income taxed	Worldwide income	Local or resident-based income
Filing requirement	Even while living abroad	Usually based on residency
Double taxation risk	Higher	Lower

Most countries focus on where you live. The US keeps a tax connection through citizenship instead.

That difference is why US expats often face ongoing filing requirements even after leaving the country.

Why does the US use citizenship-based taxation?

The system dates back to the Civil War era and is often linked to revenue needs and concerns about taxpayers avoiding US tax by living abroad.

Over time, the rule stayed in place even as global mobility became more common.

There’s still debate around whether it makes sense today. Some see it as maintaining fairness. Others see it as outdated. Either way, it remains the current framework.

Who needs to file under citizenship-based taxation?

Many US citizens abroad must file a US tax return if their income meets IRS filing thresholds or if other reporting rules apply, even if no US tax is ultimately owed.

For the 2025 tax year (filed in 2026), common baseline thresholds include (these are approximate and subject to annual IRS updates):

Single: US$15,750
Married filing jointly: US$31,500
Head of household: US$23,625
Married filing separately: US$5
Self-employed: US$400

These are starting points. In some cases, filing still makes sense even below these thresholds.

To simplify this further, here’s a quick decision view:

When US expats need to file

Situation	Filing required?
Income above threshold	Yes
Self-employed earning over US$400	Yes
Below threshold	Sometimes

This helps remove guesswork, especially if your situation isn’t straightforward.

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What income do you need to report?

US citizens generally need to report all worldwide income, regardless of where it was earned.

Including but not limited to:

Salary from a foreign employer
Freelance or self-employment income
Rental income
Dividends and capital gains
Certain foreign pensions (treatment can vary)

A common misunderstanding is that income earned abroad is not subject to US tax. For US citizens, that is generally not the case.

However, reporting income does not automatically mean paying tax on it twice. That depends on how relief mechanisms apply.

How citizenship-based taxation affects you (step-by-step)

To make this easier to follow, here’s how citizenship-based taxation typically applies in practice:

Step 1 – Determine if you meet IRS filing thresholds
Check your income against annual IRS limits and filing rules.

Step 2 – Report all worldwide income
Include salary, freelance income, investments, and other earnings, regardless of where they were earned.

Step 3 – Apply tax relief strategies
Use the Foreign Tax Credit (FTC) or Foreign Earned Income Exclusion (FEIE) to reduce or eliminate double taxation.

Step 4 – Check additional reporting requirements
Review whether you need to file forms such as the FBAR or Form 8938 for foreign accounts and assets.

Step 5 – File annually, even if no tax is due
Many US expats still need to file, even when their final US tax bill is zero.

Once you understand this process, it becomes easier to see how each part of the system fits together in real-world situations.

How do US expats avoid double taxation?

Most US expats reduce or eliminate double taxation using the Foreign Tax Credit, the Foreign Earned Income Exclusion, or tax treaties.

To get a clearer picture, here’s a simple breakdown of the main ways US expats reduce or avoid double taxation:

Ways US expats reduce double taxation

Method	What it does	Best for
Foreign Tax Credit (FTC)	Offsets US tax using foreign taxes paid	High-tax countries
Foreign Earned Income Exclusion (FEIE)	Excludes earned income (up to US$130,000 for 2025)	Lower-tax countries
Tax treaties	Help coordinate how income is taxed	Specific situations

In many higher-tax countries, such as the UK and Canada, the Foreign Tax Credit often significantly reduces US tax.

Still, results aren’t always identical. Timing differences, income types, and local tax rules can affect the final outcome.

What is the saving clause, and why does it matter?

Most US tax treaties include a saving clause that generally allows the US to continue taxing its citizens as if the treaty did not exist, although some exceptions may apply.

This is where expectations and reality can differ.

Many people assume a tax treaty fully removes US tax obligations. In practice, treaties often address specific types of income but don’t override the overall system.

Additional reporting requirements for US expats

Some reporting rules go beyond your main tax return. Here’s a quick overview of the most common forms US expats may need to file:

Common reporting forms for US expats

Form	Purpose	Threshold
FBAR (FinCEN 114)	Reports foreign bank accounts	US$10,000 combined at any time
Form 8938	Reports specified foreign financial assets	Generally US$200K+ (single abroad) / US$400K+ (joint)
Form 8621	Reports certain foreign investment funds (PFICs)	Based on ownership and events, not a fixed threshold

These forms don’t always increase your tax bill, but missing them can lead to penalties.

Real example: how citizenship-based taxation works

Imagine a US citizen living in the UK:

Earns income and pays UK taxes
Files a UK tax return locally
Still files a US tax return

In many cases, the Foreign Tax Credit reduces or eliminates additional US tax.

Now compare that to someone in a lower-tax country. They might rely more on the FEIE, and the outcome could look very different.

Pros and cons of citizenship-based taxation

Citizenship-based taxation has both policy benefits and practical drawbacks, especially for Americans living abroad.

To make the trade-offs easier to see, here’s a simple breakdown:

Pros and cons of citizenship-based taxation at a glance

Pros	Cons
Helps limit tax avoidance	Complex filing requirements
Maintains a global tax link	Ongoing reporting burden
Supports the US revenue system	Can be confusing for expats

There’s still no clear agreement on how well this system works today.

From a policy perspective, it has its logic. From a practical standpoint, it can feel like extra work for people who live fully outside the US.

Frequently Asked Questions

Do US citizens abroad need to file even if they pay foreign taxes?

Yes, in many cases. Paying foreign taxes may reduce or eliminate US tax, but it does not automatically remove your US filing requirement.

Can you use both the Foreign Tax Credit and FEIE?

Sometimes. You can use both in the same return, but not on the same income. The interaction between them can affect your overall tax outcome.

What happens if you don’t file while living abroad?

Penalties may apply, and catching up later can become more complex. The IRS does offer programs to help late filers, but staying compliant early is usually simpler.

Are foreign bank accounts always reportable?

Not always. Reporting depends on thresholds, but many expats meet those thresholds without realizing it, especially if they have multiple accounts.

Is citizenship-based taxation likely to change?

There are ongoing discussions about reform, but no confirmed changes apply for the 2025 tax year filed in 2026. For now, the system remains in place.

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Clark Stott has been with Expat Tax Online since 2015. Being a dual national based in the UK, Clark has unique experience helping US citizens (and Accidental Americans) become tax compliant via the Streamlined Tax Amnesty program. Clark likes to help Americans in the UK keep their tax situations as simple as possible to avoid harsh IRS treatment.