US expat working in the UK reviewing tax documents with a US and UK tax advisor

Working in the UK? US Expat Tax Awareness Explained

Working in the UK can be an exciting opportunity for US citizens, green card holders and American expats. Whether you have moved to London for employment, business, family, education or a long-term career opportunity, the UK offers access to one of the world’s most established professional and financial markets.

However, one area that many US expats underestimate is tax. Living or working in the UK does not automatically remove your US tax responsibilities. At the same time, becoming UK tax resident may also bring HMRC reporting obligations. This means many Americans working in Britain need to consider both US and UK tax systems at the same time.

This is where proper US/UK tax awareness becomes essential. Mistakes can lead to missed filings, unnecessary stress, double taxation concerns, penalties, or confusion over which country has the right to tax certain types of income.

Why US Expats in the UK Need Tax Awareness

The United States has a different approach to taxation compared with many other countries. US citizens and resident aliens generally remain subject to US tax reporting requirements even when they live abroad. This can come as a surprise to Americans who assume that paying UK tax through employment or self-employment is enough.

For example, a US citizen working in London may pay UK income tax through PAYE. However, that does not automatically mean their US tax filing obligations disappear. Depending on their income level, filing status, bank accounts, investments and personal circumstances, they may still need to file a US federal tax return and possibly additional forms.

For UK purposes, tax residence is also important. HMRC uses the Statutory Residence Test to determine whether someone is UK tax resident for a particular tax year. Once you are UK tax resident, your UK tax position may be affected by your employment income, foreign income, gains, savings, investments and other sources of wealth.

The key point is simple: if you are American and working in the UK, your tax position should not be treated casually.

US Tax Responsibilities While Working in the UK

Many US expats working in the UK need to consider whether they are required to file a US tax return. This may apply even if they do not owe any US tax after reliefs, credits or exclusions are considered.

Common US tax matters for Americans in the UK may include:

US Federal Income Tax Returns

US citizens and certain US resident aliens living abroad may still need to file annual US tax returns. This can include reporting salary, self-employment income, rental income, investment income, dividends, capital gains and other income.

Many expats wrongly assume that if their income is earned in the UK and taxed in the UK, it does not need to be reported to the IRS. In many cases, that assumption is incorrect. Reporting and payment are not the same thing. You may have a filing requirement even if the final US tax due is reduced or eliminated by available tax relief.

Foreign Earned Income Exclusion

Some US expats may qualify for the Foreign Earned Income Exclusion, which can allow eligible individuals to exclude a portion of foreign earned income from US taxable income. However, this is not automatic. It must be claimed correctly, and eligibility depends on specific rules.

It is also important to understand that the Foreign Earned Income Exclusion does not cover every type of income. It generally relates to earned income, not investment income, rental profits, dividends, pension income or capital gains.

Foreign Tax Credit

The Foreign Tax Credit may also help reduce double taxation where tax has already been paid to the UK. For many US expats in the UK, this can be highly relevant because UK tax rates may be significant.

However, the correct approach depends on the individual’s circumstances. Choosing between claiming the Foreign Earned Income Exclusion and using Foreign Tax Credits requires care, especially where pensions, investments, future planning, capital gains or UK tax exposure are involved.

FBAR and Foreign Account Reporting

US expats in the UK may also need to consider foreign bank account reporting. If the combined value of certain non-US financial accounts exceeds the relevant reporting threshold at any point during the year, an FBAR filing may be required.

This can include UK bank accounts, savings accounts, investment accounts and certain other financial accounts. The FBAR is separate from the US tax return, and many expats only discover the requirement after they have already missed previous filings.

This is one of the most common areas where US expats need professional guidance because the rules can apply even where no additional tax is due.

UK Tax Responsibilities for US Expats

Working in the UK also brings UK tax considerations. Depending on your employment status, residence position and income sources, you may need to deal with HMRC as well as the IRS.

UK Employment Income

If you are employed in the UK, your employer may deduct income tax and National Insurance through PAYE. For some individuals, PAYE may deal with most UK employment tax obligations. However, it does not automatically cover every situation.

You may still need to file a UK Self Assessment tax return if you have additional income, are self-employed, have rental income, claim certain reliefs, receive foreign income, have capital gains, or fall into other HMRC reporting categories.

UK Tax Residence

Your UK tax residence position is highly important. The UK tax year runs from 6 April to 5 April, which is different from the US calendar tax year. HMRC’s Statutory Residence Test considers factors such as days spent in the UK, work patterns, accommodation, family ties and other connections.

This means that a person may need careful advice when arriving in the UK, leaving the UK, splitting time between countries, or working internationally.

Foreign Income and Gains

US expats in the UK may also need to consider how foreign income and gains are treated. This can include US investment income, rental income, pension income, business income or gains from selling assets.

The UK rules in this area can be complex, particularly for internationally mobile individuals. A tax position that appears simple at first may become more complicated when both HMRC and IRS reporting are considered together.

Common Mistakes US Expats Make

US expats working in the UK often make mistakes because they assume one tax system automatically recognises the other. Unfortunately, US and UK tax rules are not identical.

Common mistakes include assuming UK tax payment removes the need for US tax filing, failing to report UK bank accounts, forgetting about FBAR, misunderstanding the Foreign Earned Income Exclusion, ignoring US state tax issues, failing to plan before selling assets, overlooking pension treatment, and waiting until deadlines are close before seeking advice.

Another common mistake is using a tax adviser who only understands one side of the issue. A UK-only accountant may not understand IRS reporting. A US-only tax preparer may not understand HMRC rules. For US expats in the UK, the best approach is usually to seek advice from professionals who understand both systems.

Why Professional US/UK Tax Advice Matters

US and UK tax compliance is not simply about filling in forms. It is about understanding how both tax systems interact.

A US expat working in the UK may need to consider income tax, foreign tax credits, foreign earned income exclusion, FBAR, FATCA, pensions, investments, capital gains, property, self-employment, business ownership, state tax, UK Self Assessment and future relocation plans.

Professional advice can help reduce the risk of mistakes and provide clarity over what needs to be filed, when it needs to be filed, and how your affairs should be structured.

For many expats, the value of good advice is not only financial. It also provides peace of mind. Knowing that both your IRS and HMRC obligations have been considered properly allows you to focus on your work, family and life in the UK.

Contact Xerxes Associates LLP

If you are a US expat working in the UK and need help understanding your US and UK tax obligations, Xerxes Associates LLP can assist.

Xerxes Associates LLP is a London-based firm of specialist US and UK tax advisers. The team provides support for US citizens living in the UK, UK expats in the US, and individuals with cross-border tax requirements. Their services include US federal and state income tax returns, UK Self Assessment tax returns, personal tax planning, FBAR and ITIN assistance, consultations and expat tax support.

To discuss your circumstances, contact Xerxes Associates LLP using the details below:

Xerxes Associates LLP
Warnford Court
29 Throgmorton Street
London
EC2N 2AT
United Kingdom

Telephone: +44 (0)207 411 9026
Alternative Number: +44 (0)207 411 9051
Email: info@xerxesllp.com
Website: xerxesllp.com

If you are unsure whether you need to file in the US, the UK, or both, it is better to seek advice early rather than wait until a deadline or tax issue arises.

FBAR vs FATCA Explained for US Citizens in the UK

FBAR vs FATCA Explained for US Citizens in the UK

For US citizens living in the UK, one of the most confusing aspects of tax compliance is understanding the difference between FBAR and FATCA reporting. Both require disclosure of foreign financial accounts and assets, and both are enforced by US authorities, but they serve different purposes and have separate filing requirements.

Many expats either misunderstand these obligations or assume that filing one satisfies the other. This is incorrect and can lead to serious compliance issues.

This guide breaks down FBAR and FATCA in a clear, practical way so US expats in the UK can understand exactly what is required and avoid costly mistakes.

What Is FBAR?

FBAR stands for Foreign Bank Account Report.

It is formally known as FinCEN Form 114 and is filed with the Financial Crimes Enforcement Network, not the IRS directly.

Who Needs to File FBAR?

You must file an FBAR if:

  • You are a US citizen or green card holder
  • The total value of your foreign financial accounts exceeds $10,000 at any point during the year

This threshold is based on the combined total across all accounts, not individual accounts.

What Accounts Must Be Reported?

FBAR covers a wide range of financial accounts, including:

  • UK current and savings accounts
  • Joint accounts (even if partially owned)
  • Investment accounts
  • Pension accounts in some cases
  • Accounts where you have signatory authority

This broad definition often catches expats off guard.

When and How Is FBAR Filed?

  • Filed annually online through the FinCEN system
  • Deadline typically aligns with US tax deadlines (with automatic extensions)
  • No tax is calculated or paid through FBAR

It is purely a reporting requirement.

What Is FATCA?

FATCA stands for the Foreign Account Tax Compliance Act.

Unlike FBAR, FATCA is enforced by the Internal Revenue Service and is part of your annual tax return.

Who Needs to File FATCA (Form 8938)?

FATCA applies when your foreign financial assets exceed higher thresholds than FBAR.

For US expats living in the UK, typical thresholds are:

  • $200,000 on the last day of the tax year
  • $300,000 at any point during the year

These thresholds vary depending on filing status.

What Assets Must Be Reported?

FATCA covers a broader range of assets than FBAR, including:

  • Bank accounts
  • Investment accounts
  • Foreign stocks and securities
  • Interests in foreign entities
  • Certain pension arrangements

This makes FATCA more comprehensive in scope.

How Is FATCA Filed?

  • Filed as part of your US tax return (Form 1040)
  • Submitted using Form 8938
  • Requires detailed reporting of asset values

Key Differences Between FBAR and FATCA

1. Filing Authority

  • FBAR is filed with the Financial Crimes Enforcement Network
  • FATCA is filed with the Internal Revenue Service

2. Reporting Thresholds

  • FBAR threshold: $10,000 (combined accounts)
  • FATCA threshold: significantly higher (starting around $200,000 for expats)

3. Scope of Reporting

  • FBAR focuses on financial accounts
  • FATCA includes a wider range of financial assets

4. Filing Method

  • FBAR is filed separately online
  • FATCA is included within your tax return

5. Purpose

  • FBAR is designed to combat financial crime and offshore tax evasion
  • FATCA is designed to ensure transparency in foreign asset reporting

Do You Need to File Both?

In many cases, yes.

If you meet the thresholds for both FBAR and FATCA:

  • You must file both separately
  • Filing one does not replace the other

This is one of the most common compliance errors among US expats.

How UK Financial Institutions Are Involved

Under FATCA, UK banks and financial institutions report information about US account holders directly to the Internal Revenue Service through agreements with HM Revenue and Customs.

This means:

  • Your accounts are already visible to US authorities
  • Non-disclosure is more likely to be detected
  • Compliance is increasingly important

Penalties for Non-Compliance

The penalties for failing to file FBAR or FATCA can be severe.

FBAR Penalties

  • Non-willful violations can result in fines
  • Willful violations can lead to significantly higher penalties

FATCA Penalties

  • Initial penalties for failure to file
  • Additional penalties for continued non-compliance
  • Potential impact on overall tax return accuracy

Given the seriousness of these penalties, accurate and timely filing is essential.

Common Mistakes US Expats Make

  • Assuming UK accounts do not need to be reported
  • Believing FBAR and FATCA are the same
  • Forgetting to include joint accounts
  • Not tracking peak account balances
  • Ignoring reporting requirements for pensions or investments

Avoiding these mistakes is critical for maintaining compliance.

Special Considerations for UK-Based Expats

Joint Accounts with Non-US Spouses

Even if your spouse is not a US citizen, joint accounts may still need to be reported.

UK Pensions

Some pension structures may fall under reporting requirements depending on how they are classified.

ISAs

While tax-efficient in the UK, ISAs may still need to be reported under FATCA rules.

How to Stay Compliant

To ensure full compliance:

  • Keep detailed records of all foreign accounts
  • Track maximum account balances during the year
  • Understand filing thresholds
  • File both FBAR and FATCA where required
  • Seek professional advice if unsure

A proactive approach reduces risk and simplifies the process.

Why Professional Guidance Matters

Given the overlap and complexity of FBAR and FATCA, many expats benefit from specialist advice.

Professional support can:

  • Identify all reportable accounts and assets
  • Ensure accurate filings
  • Reduce risk of penalties
  • Provide peace of mind

FAQs

What is the difference between FBAR and FATCA?
FBAR reports foreign accounts to FinCEN, while FATCA reports foreign assets to the IRS as part of your tax return.

Do I need to file both FBAR and FATCA?
Yes, if you meet the thresholds for both.

Are UK bank accounts reportable?
Yes, most UK accounts must be reported under FBAR and possibly FATCA.

What happens if I don’t file?
Penalties can be significant, even if no tax is owed.

How US Expats in the UK Can Reduce Double Taxation Legally in 2026

How US Expats in the UK Can Reduce Double Taxation Legally in 2026

Why Double Taxation Remains a Major Issue for US Expats

Double taxation is one of the most persistent concerns for US citizens living in the United Kingdom. The issue arises because the UK taxes individuals based on residence, while the United States taxes based on citizenship. As a result, US expats can find themselves subject to tax obligations in both countries on the same income.

In 2026, this challenge remains firmly in place. While relief mechanisms exist, they must be applied correctly and consistently. Misunderstanding how these mechanisms work often results in either overpaying tax or creating compliance risks that can surface years later during audits or reviews.

Understanding the legal tools available to mitigate double taxation is essential for protecting long-term financial stability.

Understanding How the UK and US Tax Systems Interact

The UK tax system focuses on residency status, source of income, and, in some cases, domicile considerations. The US tax system, by contrast, applies globally to its citizens regardless of where they live.

This mismatch creates complexity, particularly for employment income, self-employment income, investment returns, and pensions. Income that is fully taxable in the UK may still need to be reported in the US, even if UK tax has already been paid.

Without careful coordination, this overlap can lead to duplicated reporting, misaligned elections, and unnecessary tax exposure.

The Foreign Earned Income Exclusion Explained

One of the most commonly used tools for reducing double taxation is the Foreign Earned Income Exclusion. This allows qualifying US expats to exclude a portion of foreign earned income from US taxation if specific conditions are met.

However, the exclusion applies only to earned income and does not cover investment income, pensions, or rental income. It also requires careful consideration, as electing the exclusion can limit access to other relief mechanisms in future years.

Using the exclusion incorrectly or without long-term planning can create problems that outweigh short-term benefits.

Foreign Tax Credits and When They Are Preferable

Foreign tax credits allow US taxpayers to offset US tax liability with taxes paid to the UK. This approach is often more suitable for higher earners or those with significant non-earned income.

Unlike exclusions, tax credits preserve the ability to claim deductions and avoid disqualifying future elections. However, they require accurate matching of income categories and timing between UK and US filings.

Errors in credit calculations are a common cause of IRS queries and adjustments.

The Role of the UK–US Double Tax Treaty

The UK–US Double Tax Treaty exists to prevent double taxation and clarify taxing rights between the two countries. Treaty provisions address issues such as residency conflicts, pension taxation, business profits, and relief from double taxation.

In practice, treaty claims must be made carefully. Incorrect or inconsistent treaty positions can invalidate claims and create compliance exposure in both jurisdictions.

In 2026, treaty scrutiny is increasing, particularly where claims affect long-term tax liabilities or residency status.

Pension and Investment Planning Challenges

Pensions are a frequent source of confusion for US expats in the UK. Many UK pension structures receive favourable treatment under UK law but are treated differently under US tax rules.

Investment structures, including ISAs and collective investment schemes, can also trigger unexpected US tax consequences if not structured correctly.

Failure to align pension and investment planning with both tax systems often results in higher effective tax rates and reporting complexity.

Common Planning Mistakes That Increase Tax Exposure

Many expats inadvertently increase their tax burden through poor planning or generic advice. This is particularly common where advisers focus on one jurisdiction without understanding the other.

Frequent mistakes include: choosing the wrong relief mechanism, switching strategies year-to-year without planning, misunderstanding pension treatment, failing to coordinate filing dates, and assuming UK compliance eliminates US obligations.

These errors are often costly and difficult to unwind.

Why Specialist UK–US Tax Advice Is Essential

Reducing double taxation is not about avoiding tax, but about applying the law correctly and strategically. Specialist UK–US advisers understand how exclusions, credits, and treaty provisions interact across multiple years.

This expertise allows expats to structure their affairs in a way that is compliant, efficient, and sustainable. It also reduces the risk of audits, penalties, and retrospective adjustments.

Planning Ahead for 2026 and Beyond

Effective tax planning should be forward-looking. Decisions made in one tax year often have consequences in future years, particularly where elections and exclusions are involved.

In 2026, proactive planning is more important than ever as enforcement activity continues to increase and data matching becomes more sophisticated.

In Summary

US expats in the UK face unavoidable complexity when it comes to taxation, but double taxation is not inevitable. By understanding how the two systems interact and applying the correct relief mechanisms, expats can significantly reduce their tax burden while remaining fully compliant.

With specialist advice and careful planning, double taxation can be managed legally and effectively in 2026 and beyond.

ABOUT US

Xerxes Associates LLP was established by Naveed Lasi after having gained over a decade of industry experience with EY, Deloitte and PwC.

ADDRESS

Warnford Court, 29 Throgmorton St, London, EC2N 2AT, UK

CONTACTS

Call Us: Tel: +44 (0)207 411 9026

Fax: +44 (0)207 411 9051

E-mail Us: info@xerxesllp.com

US & UK Tax Advisors

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