UK and US corporation tax, without the GILTI or Subpart F surprise
One company touching both tax systems means two returns, two authorities, and rules — GILTI, Subpart F, the check-the-box election — that most UK accountants and US CPAs have never had to apply together. We file both sides so they reconcile, and manage the CFC exposure before it becomes a filing problem.
✓ Free and no obligation. You get a written scope and fee before any work starts.
What a cross-border group has to file
The forms and calculations that come with owning a company across the corridor.
- Form 5471Filed by US persons who own or control a foreign corporation — including a UK subsidiary.
- Form 1120The US corporate return, for any US entity in the group.
- GILTIGlobal Intangible Low-Taxed Income — can tax UK profits currently, even before a dividend is paid.
- Subpart FCertain passive or related-party income taxed to the US owner immediately.
- CTA returnThe UK Ltd's own corporation tax return, filed alongside the US side.
Who this service is for
US companies with a UK subsidiary
Your UK Ltd is a controlled foreign corporation under US rules — Form 5471, GILTI and Subpart F all potentially apply.
UK companies with a US subsidiary
Your US entity files its own Form 1120 and, depending on the state, a state return too — alongside your UK corporation tax return.
US shareholders of a UK company
Individuals or entities that are US persons and own enough of a UK company to trigger Form 5471 filing on their own US return.
Groups reconsidering their structure
Weighing a check-the-box election, or revisiting one made years ago that no longer fits how the group operates.
Setting up the structure for the first time? See UK & US market entry.
Check-the-box: corporation or disregarded?
Electing how the US treats your foreign entity changes your GILTI, Subpart F and compliance position significantly. Toggle to compare — an illustration, not advice.
Left as a corporation vs check-the-box elected
Pick a lens to see how the US tax treatment of your UK entity changes with the election.
Left as a corporation
Check-the-box elected
What's included in corporation tax (both sides)
You get a written scope first, setting out exactly what's filed and calculated on each side.
UK & US corporation tax returns
Your UK corporation tax return and any US Form 1120, prepared together so the numbers agree.
Form 5471 or Form 8858
Whichever applies to your ownership structure, prepared to the correct category of filer.
GILTI & Subpart F calculations
Worked out each year so there are no surprises on income that's taxed to the US owner currently.
Check-the-box strategy
Whether an election makes sense for your group, and the timing and mechanics if it does.
Corporate foreign tax credit
UK tax credited against US tax at the corporate level, so the same profit isn't taxed twice.
Reconciled, not just filed
Both returns checked against each other before anything is submitted, so nothing contradicts.
How cross-border corporation tax actually works
The mechanics behind the numbers, in plain English.
One company, two returns
A UK company with US ownership — or vice versa — doesn't get to pick one tax system. Both authorities want their return, and they need to agree.
What GILTI actually taxes
Global Intangible Low-Taxed Income can tax a US shareholder on UK company profits in the year they're earned, not just when a dividend is paid.
Subpart F catches different income
Certain passive or related-party income is taxed to the US owner immediately under Subpart F, separately from the GILTI calculation.
Check-the-box changes the whole picture
Electing your UK entity as disregarded removes it from CFC rules entirely — but changes what you report and how losses flow.
Form 5471 has categories
Which category of filer you are changes what schedules are required — getting this wrong is one of the most common cross-border filing errors.
UK deadlines don't move for US filing
Your UK corporation tax return is due on its own UK timetable regardless of where the US side stands — we keep both on track.
Why Taxule for corporation tax
Because a group with entities on both sides needs one team that understands both systems together.
Both returns, one team
Your UK and US corporation tax are prepared together, so nothing is filed in isolation.
CFC rules handled properly
GILTI, Subpart F and Form 5471 are core to what we do, not an occasional add-on.
Every filing scoped clearly
What's being filed, and why, is explained in your scope before we start.
How it works
- 1
Map the group
We work out exactly what filings your structure requires on each side, and which category of filer applies.
- 2
Calculate & reconcile
UK and US figures, GILTI and Subpart F where they apply, checked against each other before anything is filed.
- 3
File on both sides
Both returns submitted to their own deadlines, with a clear record of how the numbers tie together.
What clients say about corporation tax
Our previous accountant had never heard of GILTI and it showed. Taxule caught the exposure on our UK subsidiary's profits before it turned into a penalty, and now it's just part of the annual routine.
We'd been filing Form 5471 ourselves and weren't confident we had the right category of filer. Taxule reviewed it, corrected two schedules, and now files it alongside our UK return every year.
The check-the-box decision had real money on either side of it. Having it modelled properly, with the GILTI and loss implications spelled out, made it an easy call for the board.
Corporation tax questions from cross-border groups
Straight answers to what finance teams ask first.
Do I need to file Form 5471?
If you're a US person who owns or controls a foreign corporation — including a UK Ltd — you likely need to file Form 5471, with the exact schedules depending on your category of filer. We confirm your category and prepare it correctly.
What is GILTI and does it apply to my UK company?
Global Intangible Low-Taxed Income can tax a US shareholder on their share of a controlled foreign corporation's profits in the year they're earned, before any dividend is paid. Whether it applies, and how much, depends on your ownership and the entity's income.
What's the difference between GILTI and Subpart F income?
Subpart F targets specific categories of passive or related-party income and taxes it to the US owner immediately. GILTI is a broader calculation covering most other active income above a routine return threshold. A CFC can trigger both in the same year.
Should I make a check-the-box election for my UK entity?
It depends on your group's income, losses and long-term plans — electing disregarded status removes CFC rules entirely but changes how income and losses are reported. We model both outcomes before recommending one.
When is the UK corporation tax deadline?
Corporation tax is normally due 9 months and 1 day after your accounting period ends, with the return itself due 12 months after. We track this alongside your US filing dates so nothing is missed on either side.
Other business services in the corridor
Let's get both returns telling the same story.
A free consultation, no obligation. Tell us how your group is structured and we'll map exactly what needs filing on each side.
