Form 8938 and friends: which international forms do you actually owe?

Figures relate to tax year 2025 (US)

Form 8938 is the one most Americans in Britain have heard of, and it is rarely the only one they owe. A UK company, a fund inside an ISA, an inheritance from a parent — each triggers a different international form, with its own threshold and its own penalty regime.

The forms are not interchangeable, and filing one never covers another. So this guide works as a routing map. It walks through the situations that create a filing duty, names the form each one triggers, and shows how they interact when several apply at once.

Key takeaways

• Form 8938 reports foreign assets on your return, starting at $200,000 for a single filer abroad.
• A UK limited company usually triggers Form 5471, whatever its size or profit.
• Foreign gifts and inheritances above $100,000 need Form 3520, even when no tax is due.
• Funds inside an ISA are usually reportable investments needing Form 8621 each year.
• Most of these carry a $10,000 starting penalty and can hold your return open indefinitely.

Why are there so many forms?

Because each was written for a different worry. One tracks assets, another tracks companies, a third tracks gifts from abroad. They accumulated over decades without anyone consolidating them, so an ordinary British life can trip several at once.

The practical effect is that no single form tells the whole story. You work out your filing set situation by situation, then check how the pieces overlap. Getting that map right in year one saves the same work every year afterwards.

Which form does each situation trigger?

Start with what you actually hold rather than with the forms themselves. The table below covers the situations we meet most often among Americans in Britain, and it is the fastest route to your own answer.

Read that as a starting map rather than a ruling. Each row hides conditions, exceptions and definitions that decide the real answer for your facts. But if a row describes your situation, that form deserves a proper look before you file anything. Guessing here is what turns an administrative task into a penalty letter years later.

The forms do not substitute for each other. Six filings sound absurd until you price a single missed one.

What is Form 8938, and when does it apply?

It is the Statement of Specified Foreign Financial Assets, attached to your Form 1040. Americans abroad file it once assets pass $200,000 at year end for single filers, or $400,000 filing jointly, with higher any-time-during-the-year tests alongside.

According to the IRS guidance for Form 8938 (opens in a new tab), it covers far more than accounts. Shares held directly count, as do pension interests, loans to foreign persons and insurance contracts with cash value. Real estate you own personally stays outside it.

The company form: Form 5471

Own ten percent or more of a UK limited company and this one usually applies. Size is irrelevant here, since a one-person consultancy files the same form as a substantial subsidiary. Only the schedules differ, depending on your category of filer.

Form 8938 may then cover the same shares, which is where the duplicate-reporting exception earns its keep. Rather than listing the holding twice, you point the asset statement at the company form and let the detail live there. It saves duplication without hiding anything from the agency.

The penalty starts at $10,000 per company per year, and an unfiled 5471 holds the whole return open. In our practice we see this form missed more often than any other, usually by people who set up a company on an accountant's advice without mentioning their citizenship.

The fund form: Form 8621

Almost every UK fund, unit trust and investment ISA holding counts as a passive foreign investment company. Each one generally needs its own annual form. The computations run under rules designed to discourage the whole arrangement, and they are unforgiving.

This is why a portfolio of five funds becomes five forms a year. Our guide to why your ISA is a US tax problem covers the tax treatment behind it, and the reporting burden is what usually persuades people to restructure.

The gift form: Form 3520

Receiving more than $100,000 from a non-American individual in a year triggers this one. No tax is due on the gift itself, which is precisely why people skip it. The form is informational, and the penalty for missing it is not.

Inheritances count, and so do gifts from parents helping with a house deposit. The penalty can reach 25% of the amount received, which turns generosity into a genuinely expensive event. Foreign trusts have their own reporting under the same form family.

How do you work out your own filing set?

Inventory first, forms second. Almost every mistake we correct began with someone reaching for a form before listing what they hold. Form 8938 is usually the anchor, because its threshold test forces the inventory anyway. Work through this sequence once a year, ideally each spring:

1. List every account, investment, company interest, pension and trust connection you hold.
2. Add anything received during the year — gifts, inheritances, share awards, distributions.
3. Convert the values to dollars, using the maximum during the year for asset tests.
4. Test the asset thresholds for your filing status and residence.
5. Check each company, partnership and fund holding against its own form.
6. Note where the duplicate-reporting exception lets one form cover another's detail.
7. Keep the working list, then update it each year rather than rebuilding it.

The duplicate-reporting exception worth knowing

Where an asset already appears on certain other international forms, Form 8938 does not need its detail repeated. Instead you record how many of those forms you filed, and the detail lives there.

According to the IRS instructions, the qualifying forms cover foreign trusts, corporations, partnerships and investment funds. So an American reporting a UK company on Form 5471 does not re-list those shares asset by asset. You still complete the summary section, which tells the agency where to look.

What about trusts and pensions?

UK trusts are the sharpest edge here. An interest in a foreign trust can trigger annual reporting quite apart from any distribution, and family arrangements set up by British relatives rarely consider an American beneficiary.

Pensions sit more comfortably. Workplace and personal schemes are generally reportable assets on Form 8938, yet the treaty usually protects the growth inside them from current tax. So the duty is disclosure rather than payment, which is a far easier conversation.

Our guide to UK pensions and US tax covers that treatment in detail. The practical rule is simple: report the scheme, claim the treaty position where it applies, and never assume silence is safer than disclosure.

A worked example

Take an illustrative example. An American in Leeds runs a consultancy through a UK limited company, holds an ISA containing three funds, and received £120,000 from her father toward a house in 2025. Her savings and investments total roughly $260,000.

Her filing set runs to four forms plus the FBAR. Form 8938 covers the threshold breach, Form 5471 the company, three Form 8621 filings the funds, and Form 3520 the gift. None of them creates tax. Every one of them carries a five-figure penalty if skipped.

The mistakes and penalties that follow a missed form

International reporting failures rarely announce themselves. No letter arrives, no tax goes unpaid, and the problem surfaces years later. These are the patterns behind most of the repair work we do:

• Assuming the FBAR covers everything, so the return goes in with no Form 8938 attached.
• Setting up a UK company without telling anyone about US citizenship, and missing Form 5471 for years.
• Treating an ISA as tax-free and never reporting the funds inside it.
• Ignoring a parental gift because no tax was due on receiving it.
• Testing only the year-end value and missing the higher any-time threshold.
• Filing forms separately by post when they belong inside the tax return.

The statute point ties them together. An unfiled international form can hold the limitation period open on your entire return, sometimes indefinitely. So one missing schedule keeps every other item on that return examinable long after you assumed the year had closed.

What if past years are already wrong?

Usually the streamlined procedures cover it, because they rebuild three years of returns with the correct forms attached. Our streamlined filing guide walks through the whole package, and our free eligibility checker narrows the route in two minutes.

The delinquent FBAR route does not help here, because it only repairs account reports. Anything belonging on the return itself is a returns problem, as our guide to delinquent FBAR submissions explains. Choosing the right door first is what protects the penalty relief.

How US UK Tax Accountants helps

We map the whole filing set before preparing anything, so the forms match the life rather than the other way round. Our FBAR and FATCA reporting service covers the asset statement, the account reports and the company, fund and gift forms that travel with them.

One senior specialist owns the file, on a fixed fee agreed in writing before work begins. Where past years missed a form, we scope the repair honestly before touching anything.

Find your filing set this year

If nobody has ever listed which international forms your situation triggers, the odds of a gap are high. Tell us what you hold and what you received. We will map the set, prepare what is needed, and quote a fixed fee in writing. Book a consultation and hear back within one working day.

Last reviewed 9 September 2026 by the US UK Tax Accountants Tax Team. This article is general information, not personal tax advice — speak to a qualified US/UK tax adviser about your own position.

For the neighbouring question, Form 3520: what to do when your UK family sends you money walks through it in detail.