Resources · Insights
Cross-border tax insights & guides
Clear, reviewed guidance on US–UK tax for expats, dual citizens and cross-border businesses. Each article is written by our team and checked for IRS or HMRC accuracy — written to answer the real questions people ask before they pick up the phone.
Business & Self-Employment10 guides
How UK Corporation Tax and US Tax Interact for American-Owned Companies
A US-owned UK company can face tax in both countries on the same profits. Here's how UK Corporation Tax, US tax on the owner, the treaty and foreign tax credits fit together — and where double taxation can still slip through.
Sole Trader or Limited Company for an American in the UK?
For a US citizen in the UK, the sole-trader-versus-limited-company decision isn't just a UK question — your structure choice has major US tax consequences (Form 5471, GILTI, self-employment tax). Here's how to think about it on both sides of the Atlantic.
Self-Employed in the UK? Your US Tax Obligations Explained
An American self-employed in the UK files in both countries — but the US-UK Totalization Agreement usually exempts you from US self-employment tax. Here's how your UK and US obligations fit together, and the certificate of coverage that saves you 15.3%.
Section 962 Election Explained for US Owners of UK Companies
A Section 962 election lets a US individual be taxed on GILTI/NCTI at corporate rates and credit the company's UK tax — often the most effective way to cut double taxation on a UK company's retained profits. Here's how it works and when to use it.
Running a UK Limited Company as a US Citizen: The Complete Overview
Owning a UK limited company as a US citizen means navigating two tax systems at once. This overview maps every US obligation a UK Ltd creates — Form 5471, GILTI/NCTI, FBAR, profit extraction — and how they fit together.
GILTI and NCTI Rules for Americans with UK Companies
GILTI — renamed NCTI for tax years beginning after 2025 — can tax a US owner of a UK limited company on profits left inside the company. Here's how the regime works, what the rename changed, and the elections that reduce the hit.
Freelancer or Contractor in the UK: What US Tax Forms Do You Need?
An American freelancing or contracting in the UK won't get a 1099 from UK clients — but still self-reports to the IRS. Here's the exact checklist of US forms you need, why the UK works differently, and the contractor-versus-employee question.
Form 5471 Explained for Americans in the UK
Form 5471 is the IRS information return for US owners of foreign corporations — including UK limited companies. Here's who has to file it, the filer categories, the schedules, the $10,000 penalty, and how it fits with GILTI and the check-the-box election.
Do US Citizens Need to Report a UK Limited Company to the IRS?
Yes — a US citizen who owns a UK limited company almost always has US reporting obligations, separate from any tax owed. Here's exactly which forms apply (5471, 8858, FBAR, 8938, 926), when they're due, and the penalties for getting it wrong.
Check-the-Box (Form 8832) for a UK Limited Company: When It Helps a US Owner
A check-the-box election can reclassify a single-owner UK limited company as a disregarded entity for US tax — removing Form 5471 and GILTI/NCTI. But it brings self-employment tax and a deemed liquidation. Here's when it helps and when it hurts.
Property, Gains & Estate9 guides
The US-UK Estate and Gift Tax Treaty Explained
Separate from the income tax treaty, the 1980 US-UK Estate and Gift Tax Treaty allocates death-tax rights between the two countries. Here's how 'treaty domicile' tie-breakers work, what protection it offers Americans, and why the 2025 UK reforms made it more important.
US Tax on UK Rental Income: A Guide for American Landlords
UK rental income is taxable in both the UK and the US for American landlords. Here's how to report it on Schedule E, why US depreciation is mandatory (and bites on sale), and how the foreign tax credit prevents double taxation.
UK Property and US Tax: The Complete Guide for Americans
Owning UK property as a US citizen means two tax systems apply to the same home — at purchase, while renting, on sale, and on death. This guide maps the whole landscape: CGT, rental income, the §121/PRR mismatch, the foreign-mortgage trap, and reporting.
UK Inheritance Tax vs US Estate Tax: What Americans with UK Property Need to Know
UK inheritance tax and US estate tax can both reach a US citizen's UK property — but they're built on different foundations, and the UK's 2025 shift to a residence-based regime changed the rules. Here's how the two systems compare and where the treaty helps.
UK Capital Gains Tax vs US Capital Gains Tax on Property
The UK and US both tax property gains, but they measure and rate them differently — UK in pounds with its own reliefs, US in dollars with depreciation and currency effects. Here's how the two systems compare and how the foreign tax credit reconciles them.
Selling a UK Home as a US Citizen: Capital Gains and the §121 Exclusion
Selling your UK home as an American can be tax-free in the UK under Private Residence Relief — but the US only excludes $250k/$500k under Section 121, and a separate Section 988 mortgage gain can still bite. Here's how it really works.
The Foreign Mortgage Currency-Gain Trap (Section 988) for Americans in the UK
Repaying or refinancing a sterling mortgage can create a separate US tax bill under Section 988 — taxed as ordinary income — even if your property sale is otherwise tax-free. Here's how this currency-gain trap works and why it surprises so many Americans.
Holding UK Property Through a Company: Should a US Citizen Do It?
Holding UK property through a limited company can solve some UK tax problems but often creates bigger US ones — Form 5471, CFC rules, and lost reliefs. Here's how to weigh the structure for a US citizen, where it helps, and where it backfires.
Buying Property in the UK as a US Citizen: Tax and Reporting Guide
Buying UK property as an American isn't a US taxable event — but it plants tax seeds. Here's what to know about Stamp Duty surcharges, why the purchase isn't FBAR-reportable, and the pound-mortgage trap that surfaces years later.
Cross-Border3 guides
Why Is My ISA a Problem for US Taxes? PFIC Rules Explained
ISAs are tax-free in the UK — but for US citizens they can be a costly trap. Most funds inside a Stocks and Shares ISA are PFICs, triggering punitive US tax and Form 8621. Here's what that means and how to think about it.
Is the 25% UK Tax-Free Lump Sum Taxable in the US?
The UK lets you take 25% of your pension tax-free — but is that lump sum taxable in the US? This is the most contested question in US-UK tax. Here are both recognised positions, the treaty reasoning, and what the conservative approach looks like.
Do I Pay US Tax on My UK Pension? What Americans in the UK Need to Know
If you're a US citizen or green card holder with a UK pension, the IRS generally taxes it as income — even though it's a UK pension. Here's how UK state, workplace and SIPP pensions are treated, how the treaty and Foreign Tax Credit fit in, and where the rules get contested.
US Expat Tax & Treaty8 guides
US Taxes on UK Investments: Practical Guide for Americans in the UK
Most UK investments create US tax complications for Americans — but there are practical steps to take. This guide covers how to invest tax-efficiently as a US person in the UK, from choosing the right funds to managing the reporting requirements.
US Tax Filing Deadlines for Americans Living in the UK (2025)
Americans in the UK get extra time to file their US tax return — but the deadlines differ from those in the US. This guide covers the automatic June extension, the October deadline, the FBAR due date, and estimated tax payment dates.
Form 1040 for Americans Living in the UK: A Practical Guide
US citizens in the UK must file Form 1040 every year on their worldwide income — UK salary, rental income, savings, and investments alike. This guide explains what the form covers, which schedules apply, and how the Foreign Tax Credit prevents double taxation.
Delinquent FBAR vs Streamlined Filing: Which Route Fixes a Missed FBAR?
If you have filed your US tax returns but missed the FBAR, you may not need the full Streamlined programme. We explain the Delinquent FBAR Submission Procedures, how they differ from Streamlined Filing, and how to tell which route fits.
IRS Streamlined Filing: How to Catch Up on US Taxes from Abroad
Behind on US tax returns while living abroad? The IRS Streamlined Foreign Offshore Procedures let non-wilful filers catch up — often penalty-free. We explain who qualifies, what's required, and the mistakes to avoid.
Is Your UK Pension Tax-Free Lump Sum Taxable in the US?
The UK 25% Pension Commencement Lump Sum is tax-free in the UK — but its US treatment is genuinely contested. We explain both recognised positions, the saving clause, Form 8833, and the risks of each approach.
The US-UK Tax Treaty Explained: How It Prevents Double Taxation
How the US-UK tax treaty prevents double taxation for Americans in the UK: residence tie-breakers, the saving clause, pensions, employment, dividends and capital gains — explained clearly.
IRS Form 8833 Explained: Who Must File It and When Is It Required?
A clear guide to IRS Form 8833 for Americans in the UK: what a treaty-based return position is, who must disclose, the penalties, and how it interacts with the FTC, FEIE, FBAR and FATCA.
US Tax3 guides
What Happens If I Haven't Filed US Taxes While Living in the UK?
Many Americans in the UK don't realise they still have to file US taxes — sometimes for years. Here's what actually happens, why it's usually fixable without penalties through Streamlined Filing, and how to catch up safely.
FEIE or Foreign Tax Credit: Which Should I Use in the UK?
Two main tools stop Americans in the UK being taxed twice: the Foreign Earned Income Exclusion and the Foreign Tax Credit. For most people in the UK, the Foreign Tax Credit is the better fit — here's why, and when the FEIE still makes sense.
Do I Need to File an FBAR? A Plain-English Guide for Americans Abroad
If you're a US citizen or green card holder with foreign bank accounts, you may need to file an FBAR. Here's who has to file, the $10,000 rule, the deadline, and what to do if you're behind.
Frequently asked questions
We publish guidance as cross-border rules change and as the questions our clients ask evolve. Every article is written by our team and reviewed for US (IRS) or UK (HMRC) accuracy before it goes live.
No. Our articles explain how the rules generally work, but cross-border tax turns on the detail of your individual situation. Use them to understand your position, then book a consultation for advice specific to you.
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