US-UK Tax Accountants for Founders
Building a company across the Atlantic multiplies your filing obligations. We prepare your US and UK taxes as one job — company, equity and personal — so nothing falls between the two systems.
Founders carry the heaviest cross-border filing load — and the biggest penalties for getting it wrong
The moment an American founds or funds a company in the UK, a second tax system bolts onto the first. Your UK company owes UK corporation tax and you owe UK Self Assessment, while as a US person you still report your worldwide income to the IRS — and owning the company drags in Form 5471, a possible GILTI inclusion, and foreign-account reporting on top.
These filings interact. Your equity, your salary, your company profits and your foreign accounts each appear on both sides of the Atlantic in different forms, on different dates, in different currencies. A generalist accountant who knows only one system will file half your picture correctly and leave the other half exposed.
We are dual-focused cross-border specialists. We prepare the US and the UK returns together, reconcile the figures across both, and make sure the founder-specific filings — the ones with five-figure penalties — are actually done.
What we prepare for founders
Controlled foreign corporation (Form 5471)
Full preparation of the US information return for your UK company, with the schedules and reference IDs the IRS expects — the filing founders most often miss.
GILTI on company profits
We calculate and report any GILTI inclusion on your share of the UK company’s earnings, and coordinate it with the UK corporation tax already paid.
Founder equity
US and UK reporting for shares, options, RSUs, QSBS / Section 1202 positions and 83(b) elections, prepared on the correct basis as your equity vests and is sold.
Dual salary & contributions
PAYE, US wage or self-employment reporting, and Social Security vs National Insurance under the totalisation agreement — so you pay each once, into the right system.
Foreign accounts (FBAR & FATCA)
FBAR and Form 8938 reporting for your personal and business accounts, so a growing balance never turns into a penalty problem.
Catch-up for unfiled years
Where you qualify, IRS Streamlined Filing to bring back years and FBARs current with no penalty, sequenced against any UK disclosure.
One team for both tax systems
Both returns, one team
US and UK prepared together, with figures and FX that reconcile across the two systems.
Founder-specific filings
Form 5471, GILTI and equity reporting are core work here, not an afterthought.
Preparation, not guesswork
Compliance grounded in your actual transactions — accurate returns, filed on time.
Built for HNW complexity
We work with founders whose company, equity and personal positions all cross the border.
Questions & Answers
As a US citizen or Green Card holder you file a US Form 1040 on your worldwide income wherever you live, plus FBAR and FATCA (Form 8938) reporting for your UK accounts. Owning a UK company usually pulls in Form 5471 for the controlled foreign corporation, a possible GILTI inclusion on the company profits, and UK corporation tax and a UK Self Assessment return in parallel. We prepare both sides together so the numbers, currencies and dates reconcile.
Form 5471 is the US information return for US persons who own or control a foreign corporation. If you hold more than a set percentage of a UK limited company, you almost certainly need to file it, and the penalties for missing it start at $10,000 per company per year. It is one of the most commonly overlooked filings for founders, and it is central to what we prepare.
We prepare the US reporting for qualified small business stock and Section 1202 positions and coordinate it with the UK treatment of the same shares, so a gain that is efficient on one side is not accidentally mishandled on the other. This is preparation and compliance work grounded in the actual transactions — we do not give investment advice.
The 83(b) election has a strict 30-day deadline from the grant, and it cannot be made late. If the window has passed we prepare your returns on the correct basis for the position you are actually in, model the ongoing US and UK tax consequences of the equity as it vests, and make sure nothing else is missed. Bring these to us early — timing is everything with founder equity.
Yes. We handle the interaction between UK PAYE, US self-employment or wage reporting, Social Security and National Insurance under the totalisation agreement, and the foreign tax credit or Foreign Earned Income Exclusion, so you are not taxed twice on the same salary and your contributions land in the right system.
This is common and fixable. Where you qualify, the IRS Streamlined Filing Compliance Procedures let non-wilful founders come forward with a set number of back years and FBARs and no penalty. We assess eligibility, prepare the package including the Form 5471s, and sequence it against any UK disclosure so the two do not undermine each other.
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Authoritative guidance from the relevant tax authorities and regulators. Always confirm current thresholds and deadlines on the official source.
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Ready to discuss your US-UK tax situation? Contact Jungle Tax today to explore how we can help with your cross-border tax compliance and planning needs.