The U.S. Cross Border Forms Guide

Who must file what?

If you feel overwhelmed by the four digit form numbers, you are not alone. The U.S. system is not built around “where you live.” It is built around whether you are a U.S. person for tax and whether you have accounts, assets, or entities outside the U.S.

The one rule that drives everything

The U.S. requires extra reporting if you are a U.S. person for tax purposes and you have foreign accounts, foreign assets, or foreign entities. A “U.S. person” can be:

A U.S. citizen, even if living abroad.
A green card holder.
A non U.S. citizen who becomes a U.S. tax resident under the substantial presence test.

This is why a Foreign citizen living in the U.S. can suddenly face the same offshore reporting as an American expat.

Step 1: Start with the three forms that catch almost everyone

Most people in either category, inbound to the U.S. or living abroad as a U.S. person, will encounter these.

1) FBAR, FinCEN Form 114: Foreign Bank Account Reporting

What it is: A standalone report of foreign financial accounts, mandated by the Bank Secrecy Act.

Who files: Any U.S. person with a financial interest in, or signature authority over, foreign accounts if the total max value exceeds $10,000 at any point in the year.

What it covers: Bank accounts, brokerage accounts, mutual funds, and certain other financial assets outside the U.S. (e.g., foreign pensions may qualify).

Key facts:

• Filed electronically with FinCEN (not IRS) by April 15 (auto-extension to October 15).

• No tax due, so just disclosure. But penalties for non-filing start at $10,000 (up to $100,000+ if willful).

• Even tax-compliant accounts (e.g., your home country savings) count.

• Overlaps with Form 8938 but isn't identical, see IRS comparison.

Common pitfall: Expats forget signature authority (e.g., on a parent's foreign account).

2) Form 8938, FATCA Reporting for Foreign Financial Assets

What it is: Disclosure of "specified foreign financial assets" (e.g., bank accounts, stocks, contracts) attached to your tax return.

Who files: U.S. persons with assets exceeding thresholds:

• Living in U.S.: $50,000+ (single) or $100,000+ (joint) on year-end; higher if max value during year.

• Living abroad: $200,000+ (single) or $400,000+ (joint) on year-end; higher if max value.

What it covers: Broader than FBAR, so includes foreign stocks/securities not in accounts, partnership interests, and more (but excludes direct real estate or currency).

Key facts:

• Filed with Form 1040; extends assessment period if omitted.

• No double-reporting for assets on other forms (e.g., Form 3520).

• Penalties: $10,000+ per year, plus 40% on underpayments tied to undisclosed assets.

Common pitfall: Inbound residents overlook that U.S. residency flips their "home" assets to "foreign" for U.S. purposes.

3) Form 8621, PFIC reporting for Passive Foreign Investments

What it is: Reporting for Passive Foreign Investment Companies (PFICs), like non-U.S. mutual funds or ETFs.

Who files: U.S. persons who are direct/indirect shareholders of a PFIC if:

• Distributions occur.

• Gain on disposition.

• Annual reporting under section 1298(f).

• Elections (e.g., QEF or mark-to-market).

What it covers: Foreign funds generating passive income (e.g., dividends, interest). Many everyday foreign ETFs qualify.

Key facts:

• Can trigger tax on "excess distributions" at top rates + interest.

• Elections can mitigate pain but require timely filing.

• Even no-activity years may need filing for QIC elections.

Common pitfall: Expats hold foreign funds without realizing PFIC status, leading to retroactive issues on sales. This is often more about compliance and calculations than immediate tax due, especially if nothing was sold and there were no significant distributions. The “pain” is how the U.S. taxes PFICs when a sale or certain distributions occur, and how time consuming the reporting can be.

Step 2: The “gateway questions” that tell you which extra forms apply

Once you know whether FBAR, 8938, and 8621 apply, the rest depends on what you own.

So you should start to ask yourself these questions.

Question A: Do you own a foreign business entity?

If yes, you may be in the foreign entity reporting forms.

Form 5471, foreign corporations

Use it when: A U.S. person must report certain interests in foreign corporations.

Why it matters: Form 5471 has its own rules and categories. This is one of the most common “I had no idea” forms for Americans who start a company abroad, or inbound residents who already own a company at home.

Form 8865, foreign partnerships

Use it when: A U.S. person files Form 8865 to report required information about certain foreign partnerships.

Form 8858, foreign disregarded entities and foreign branches

Use it when: A U.S. person owns a foreign disregarded entity or foreign branch and must satisfy reporting requirements.

Form 926, transfers of property to a foreign corporation

Use it when: A U.S. citizen or resident, or certain U.S. entities, must report certain transfers of property to a foreign corporation.

This commonly appears in restructurings, founder equity moves, IP transfers, or contributions of assets to an overseas company.

Question B: Are you foreign owned in the U.S. with related party transactions

This is more “inbound” oriented.

Form 5472, foreign owned U.S. corporations and reportable transactions

Use it when: Reporting corporations file Form 5472 to provide information when reportable transactions occur with related parties, including certain foreign owned U.S. structures.

This one matters for inbound founders who set up a U.S. LLC or corporation with foreign ownership and move money between themselves, their foreign company, and the U.S. entity.

Question C: Do you have foreign trusts, large foreign gifts, or certain non U.S. retirement structures

This is where many people get blindsided.

Form 3520, foreign trusts and certain large foreign gifts

Use it when: U.S. persons report certain transactions with foreign trusts, ownership of foreign trusts under U.S. rules, and receipt of certain large gifts or bequests from foreign persons.

Form 3520 A, foreign trust with a U.S. owner

Use it when: A foreign trust with at least one U.S. owner files this form annually to provide information.

This area is heavily fact dependent. Many people are not dealing with trusts at all. Some are, without realizing it.

Step 3: The “tax relief” forms that people confuse with reporting

Some forms reduce double taxation. They are not the same as disclosure forms.

Form 2555, Foreign Earned Income Exclusion

What it does: Helps qualified taxpayers figure the foreign earned income exclusion and housing exclusion or deduction.

This is mainly for U.S. persons living abroad with foreign earned income.

Form 1116, Foreign Tax Credit

What it does: Used to claim a foreign tax credit for eligible foreign taxes paid or accrued.

This is often relevant for both expats and inbound residents, depending on the income type and timing.

Step 4: The treaty and residency “position” forms that keep you consistent

These do not apply to everyone, but when they apply, they matter.

Form 8840, Closer Connection Exception

Who uses it: An alien individual may use Form 8840 to claim a closer connection to a foreign country exception to the substantial presence test.

This is often discussed by people who spend time in the U.S. but want to remain nonresident for U.S. tax purposes.

Form 8833, Treaty Based Return Position Disclosure

Who uses it: Taxpayers use Form 8833 to disclose treaty based return positions required under U.S. rules, including dual resident positions.

This comes up when someone is claiming a treaty benefit that overrides standard U.S. treatment.

Step 5: The “tell the truth” questions inside the normal return

These are not separate offshore forms, but they often trigger the discussion.

Schedule B (Form 1040), foreign accounts and trusts questions

Schedule B includes foreign account and foreign trust questions in Part III.

Many taxpayers answer these without understanding what they are signing. This is one reason advisers ask about offshore accounts early.

Step 6: Expatriation

Form 8854, expatriation statement

Form 8854 is used by individuals who have expatriated, including U.S. citizens who relinquish citizenship and certain long term residents who end residency. This form is part of the compliance framework around expatriation and the exit tax regime.

A practical filing map

If you are a U.S. expat

Start here:

Do you have foreign bank or investment accounts outside the U.S.
If yes, check FBAR.

Do you have foreign financial assets above FATCA thresholds.
If yes, check Form 8938.

Do you own non U.S. ETFs or mutual funds.
If yes, check Form 8621.

Do you own a foreign company, partnership, or foreign branch.
If yes, consider Form 5471, 8865, or 8858.

Are you claiming relief from double tax.
If yes, review Form 2555 and or Form 1116.

Do you have foreign trust issues or large foreign gifts.
If yes, review Form 3520 and possibly 3520 A.

If you are a foreigner living in the U.S.

Start here:

Have you become a U.S. tax resident, for example via green card or substantial presence.
If yes, your non U.S. accounts and investments can trigger the same reporting as a U.S. citizen.

Then run the same three checks:

FBAR for foreign accounts.
Form 8938 for foreign financial assets above thresholds.
Form 8621 for foreign funds like non U.S. ETFs.

If you also have inbound ownership structures, add:

Form 5472 for certain foreign owned U.S. structures and related party transactions.

If you are trying not to be treated as a U.S. resident despite days in the U.S., review:

Form 8840 and possibly Form 8833.

What this guide is not

This guide is a map of the reporting framework. It is not a substitute for determining your filing status, residency start date, treaty position, or the correct PFIC regime and elections.

PFICs, foreign trusts, and foreign business ownership are the three areas where “one wrong assumption” can change everything.

See our our other articles:

U.S. Expat Tax Rules 2026: Why Moving Abroad Rarely Lowers Tax
PFIC Rules for U.S. Expats: Why Small Foreign ETFs Cause Tax Problems
Why U.S. Expats in Europe End Up Building DIY ETF Portfolios
U.S. Expat Tax Guide 2025 | How to File Taxes While Living Abroad
State Residency for U.S. Expats | How U.S. States Tax Americans Abroad in 2025
Streamlined Filing for U.S. Expats | Catch Up on Missed Tax Returns 2025
FBAR & FATCA Explained | Reporting Foreign Bank Accounts as a U.S. Expat
U.S. Citizens Living Abroad with a Company | GILTI, Form 5471, and U.S. Tax Reporting for Foreign Companies
Foreign Earned Income Exclusion FEIE vs Foreign Tax Credit | 2025 Expat Guide

References

Report of Foreign Bank and Financial Accounts (FBAR), IRS
https://www.irs.gov/businesses/small-businesses-self-employed/report-of-foreign-bank-and-financial-accounts-fbar

Report Foreign Bank and Financial Accounts, FinCEN
https://www.fincen.gov/report-foreign-bank-and-financial-accounts

Form 8938 thresholds and filing overview, IRS
https://www.irs.gov/businesses/corporations/do-i-need-to-file-form-8938-statement-of-specified-foreign-financial-assets

Comparison of Form 8938 and FBAR requirements, IRS
https://www.irs.gov/businesses/comparison-of-form-8938-and-fbar-requirements

Instructions for Form 8621, IRS
https://www.irs.gov/instructions/i8621

About Form 5471, IRS
https://www.irs.gov/forms-pubs/about-form-5471

About Form 8865, IRS
https://www.irs.gov/forms-pubs/about-form-8865

About Form 8858, IRS
https://www.irs.gov/forms-pubs/about-form-8858

About Form 926, IRS
https://www.irs.gov/forms-pubs/about-form-926

Form 926 filing requirement page, IRS
https://www.irs.gov/individuals/international-taxpayers/form-926-filing-requirement-for-us-transferors-of-property-to-a-foreign-corporation

About Form 3520, IRS
https://www.irs.gov/forms-pubs/about-form-3520

Instructions for Form 3520, IRS
https://www.irs.gov/instructions/i3520

About Form 3520-A, IRS
https://www.irs.gov/forms-pubs/about-form-3520-a

About Form 2555, IRS
https://www.irs.gov/forms-pubs/about-form-2555

Foreign Earned Income Exclusion overview, IRS
https://www.irs.gov/individuals/international-taxpayers/foreign-earned-income-exclusion

Foreign Tax Credit overview, IRS
https://www.irs.gov/individuals/international-taxpayers/foreign-tax-credit

About Form 8833, IRS
https://www.irs.gov/forms-pubs/about-form-8833

About Form 8840, IRS
https://www.irs.gov/forms-pubs/about-form-8840

Closer connection exception guidance, IRS
https://www.irs.gov/individuals/international-taxpayers/closer-connection-exception-to-the-substantial-presence-test

About Schedule B (Form 1040), IRS
https://www.irs.gov/forms-pubs/about-schedule-b-form-1040

About Form 5472, IRS
https://www.irs.gov/forms-pubs/about-form-5472

About Form 8854, IRS
https://www.irs.gov/forms-pubs/about-form-8854

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