US Expat Tax Services UK: What a Full Service Includes

US expat tax services UK: an introduction

Good US expat tax services UK residents can rely on cover every return an American in Britain must file: the US Form 1040, the foreign account reports, any investment or company forms, and the UK Self Assessment return. The service should also make the two countries' figures agree, so UK tax counts properly against US tax. Anything less leaves gaps that tend to surface years later.

This article sets out what a full service includes and what you send to get it done. For the wider picture of filing in both countries, read our guide to US and UK tax returns. Our US federal returns service page describes how we prepare the US side.

Why US expat tax services UK residents use differ from a local accountant

A UK accountant prepares UK returns well, and a US preparer knows the IRS forms. However, an American in Britain needs both at once, with figures that match. For example, UK tax paid on your salary becomes a credit on the US return. If the two returns use different numbers, the credit is wrong. Therefore, US expat tax services UK clients need should be built around one set of figures.

Who needs these services

The IRS page for US citizens and resident aliens abroad says you are taxed on worldwide income from all sources. Consequently, every US citizen and green card holder living in Britain may need a US return. That includes people who left the US decades ago and those born abroad to American parents.

What a service does not cover

It helps to be clear about limits too. Tax return preparation is not investment advice. A preparer can show how a fund or pension is taxed, but should not tell you what to buy or sell. Likewise, US expat tax services UK families use do not replace an immigration or legal adviser. In short, the service prepares and files; your other advisers handle the rest.

What US returns does a full service prepare?

A full service prepares the Form 1040 with the schedules and forms that relieve double tax. Usually that means Form 1116 for the foreign tax credit, Form 2555 for the exclusion, or both.

The Form 1040 and its deadlines

Form 1040 is the annual US individual income tax return. If you live abroad on the due date, the IRS gives an automatic two-month extension to 15 June. You can ask for a further extension to 15 October on Form 4868, filed before the June date. However, interest runs on unpaid tax from 15 April. Our article on US tax deadlines for Americans abroad sets out each date.

State returns

Some Americans also have a US state return to consider. A few states continue to treat former residents as resident after they move abroad, especially if they keep a home or close ties there. Each state applies its own rules. Therefore, a full service asks where you lived before you left and whether you kept property there.

The foreign tax credit

The foreign tax credit is a dollar-for-dollar US credit for income tax paid abroad. You claim it on Form 1116. Because UK income tax rates are often higher than US rates, the credit frequently removes US tax on UK salary. Moreover, unused credits can carry forward to later years. That makes the credit the usual choice for higher earners.

The foreign earned income exclusion

The foreign earned income exclusion removes some foreign earnings from US taxable income. The IRS page on figuring the exclusion sets the cap at $130,000 for 2025 and $132,900 for 2026. You qualify through the bona fide residence or physical presence test, the latter needing 330 full days abroad. Furthermore, a good service models both the credit and the exclusion before choosing.

Treaty positions

Some positions rely on the US-UK treaty, such as the treatment of UK pension contributions. When a return takes a treaty position that changes the tax, you may need to disclose it. The IRS page on Form 8833 explains that disclosure, which section 6114 requires.

Which foreign account and asset reports are included?

A full service includes the FBAR and, where thresholds are met, Form 8938. These are reports, not tax returns, but the penalties for missing them are high.

The FBAR

The FBAR is FinCEN Form 114, the annual report of foreign financial accounts. The IRS FBAR page says you file when your foreign accounts together exceed $10,000 at any time in the year. It is due on 15 April, with an automatic extension to 15 October. You file it electronically through FinCEN's BSA E-Filing System, separately from the tax return.

Form 8938

Form 8938 reports specified foreign financial assets with the tax return. The IRS comparison of Form 8938 and FBAR requirements sets higher thresholds for people living abroad. For a single filer, they are $200,000 at year end or $300,000 at any time. For a married couple filing jointly, they are $400,000 or $600,000. Therefore, many people file an FBAR but not Form 8938.

Accounts that surprise people

In our experience, a few accounts are often missed. Joint accounts with a non-US spouse count in full. Similarly, accounts you can sign on but do not own, such as a company account, may need reporting. Premium Bonds and some pensions raise their own questions. A careful service asks about each one rather than relying on a bank list.

What about UK funds, companies and trusts?

A full service flags investment and company forms that many preparers overlook. The most common are the PFIC form for UK funds and Form 5471 for UK companies.

UK funds and Form 8621

A passive foreign investment company, or PFIC, is a non-US company or fund that meets an income or an asset test. The Instructions for Form 8621 set the tests at 75% passive income or 50% passive assets. In practice, most UK unit trusts, OEICs and investment trusts fall within them. Our guide to PFIC rules for UK funds explains the reporting and the elections.

UK companies and Form 5471

If you own or run a UK limited company, US rules can apply to it. The IRS page on Form 5471 covers certain US officers, directors and shareholders of foreign corporations. Consequently, a contractor with a one-person UK company often needs this form. The penalty for missing it is significant, so it belongs in the scope.

Trusts and gifts

UK trusts and large gifts from non-US relatives can trigger other US forms. These are less common, but a full service asks about them each year. Where they apply, we prepare them with the main return.

What does the UK side of the service cover?

The UK side covers your Self Assessment return and the relief for any US tax you pay. It also covers registration and, for some people, the new digital reporting rules.

Self Assessment deadlines

The UK tax year runs from 6 April to 5 April. GOV.UK sets out the Self Assessment deadlines. You must tell HMRC by 5 October if you need to file for the previous year. For 2025 to 2026, paper returns are due by 31 October 2026 and online returns by 31 January 2027. Any tax owed is also due on 31 January.

Relief for US tax

If you pay US tax on income the UK also taxes, the UK may give credit. GOV.UK explains how to claim relief if you are taxed twice, usually as Foreign Tax Credit Relief on your return. The order in which each country gives credit depends on the type of income and the treaty. Therefore, the UK and US returns need preparing together, not months apart.

Payments on account

Payments on account are advance payments towards next year's UK tax bill. GOV.UK explains that payments on account are due by 31 January and 31 July. Any balance follows on 31 January after the tax year ends. Consequently, a first year of rental or freelance income can produce a larger January bill than expected. We show you the payment dates on every return.

Making Tax Digital

Making Tax Digital for Income Tax is HMRC's system of quarterly digital updates. According to GOV.UK guidance on signing up for Making Tax Digital for Income Tax, it applies from 6 April 2026 if your self-employment and property income is over £50,000. Americans with UK rental property or freelance work should check whether it applies. Our UK Self Assessment service covers both returns and the quarterly updates.

What do you send to get started?

You send your UK income records, your account balances and last year's returns from both countries. A good service then asks follow-up questions rather than guessing.

Income records

For employment, your P60 and any P11D are usually enough. For self-employment or rental income, you send a summary of income and expenses. Additionally, dividend and interest statements cover your investment income. Because both returns use the same figures, you send them once.

Accounts and investments

For the FBAR, we need the highest balance of each account during the calendar year. Most UK banks show this on statements or will provide it. For funds, we need purchase dates, amounts and annual statements. Pension statements help with the treaty position.

Family details

Your filing status depends on your spouse's nationality and income. Children matter too, because the US child tax credit needs a Social Security number. The IRS page on the child tax credit says the number must be valid for employment and issued before the return's due date. Therefore, we check each child's number early.

Returns from earlier years

Last year's returns from both countries are the best starting point. They show what was claimed, which elections were made and what carries forward. If you have not filed US returns before, say so at the start. In that case, US expat tax services UK residents need begin with a catch-up, usually through the IRS Streamlined procedures, before the first regular year.

How often the work happens

Most of the work falls once a year, after the UK tax year closes in April. However, some people need more than one contact a year. Landlords under Making Tax Digital send quarterly updates. Similarly, anyone paying US estimated tax may need payments during the year. A good provider of US expat tax services UK residents use plans these dates with you in advance.

A worked example of US expat tax services UK families use

Consider a typical case. Daniel is a US citizen living in Manchester with his British wife and two children. He earns a UK salary, rents out a flat and holds UK funds in an ISA. His wife has her own savings in her name.

First, we prepare his UK Self Assessment return, including the rental income. Next, the US return uses the same figures, with Form 1116 for the UK tax. Because his wife is not a US person, he files as married filing separately. Additionally, we prepare Form 8621 for each fund and an FBAR for his accounts. His Form 8938 is not needed, because his assets are below the threshold for people abroad. As a result, both returns agree and the UK tax counts fully against US tax. This is an illustrative example, not a real client.

How US UK Tax Experts can help

US UK Tax Experts provides the US expat tax services UK residents need, preparing US and UK returns from one file so the two agree. The scope covers the Form 1040, the FBAR, Form 8938, PFIC and company forms, and UK Self Assessment. We work out the best mix of credit and exclusion and explain each choice. We prepare and file returns; we do not give investment advice.

Conclusion

A full service for an American in Britain is more than a US return. It covers the account reports, investment and company forms, and the UK return, all from one set of figures. When choosing US expat tax services UK residents should check that every one of those pieces is in scope.

Contact us

If you want to discuss US expat tax services UK filers need, email hello@usuktaxexperts.com or use our contact form. Tell us what income you have and which returns you filed last year. We reply within one working day.