Plenty of Americans in the UK do the sensible British thing and run their business through a limited company. What many do not realise is that owning shares in a UK 'Ltd' can trigger one of the most demanding US tax forms in existence: Form 5471, the Information Return of US Persons With Respect to Certain Foreign Corporations. It carries a $10,000 penalty per form per year for non-filing, and the rules behind it — controlled foreign corporations, Subpart F and GILTI — can tax your company's profits before you have taken a penny out. This guide explains when you must file and what is at stake.
What is Form 5471?
Form 5471 is an information return that certain US persons must file when they are officers, directors or shareholders of a foreign corporation. For an American in the UK, the 'foreign corporation' is typically your own UK limited company. The form discloses the company's ownership, its financial statements, and various schedules about its income and earnings, so the IRS can see inside a non-US company that a US taxpayer controls or has a significant stake in. It is filed with your personal US tax return, not separately.
Who has to file?
Form 5471 has several 'categories of filer', and which one you fall into determines how much of the form you complete. In broad terms you may need to file if you are a US person who:
- Owns 10% or more of a foreign corporation (by vote or value).
- Is an officer or director of a foreign corporation in which a US person acquires a 10% stake.
- Acquires or disposes of shares crossing the 10% threshold, or whose ownership changes by certain amounts.
- Controls a foreign corporation (generally more than 50%) for an uninterrupted period of at least 30 days — making it a 'controlled foreign corporation'.
- Is a US shareholder of a controlled foreign corporation (CFC).
For the typical American who owns most or all of a UK company, several of these apply at once, and the company is usually a 'controlled foreign corporation' — which brings the most demanding version of the form and the anti-deferral rules below.
What is a Controlled Foreign Corporation (CFC)?
A foreign corporation is a CFC if US shareholders who each own at least 10% together own more than 50% of it. A UK company wholly owned by one American is therefore a CFC. The label matters because CFCs are subject to the US 'anti-deferral' regimes — Subpart F and GILTI — which can require you to pay US tax on the company's profits in the year they arise, even if the company retains them and pays you nothing. This is the part that genuinely surprises owner-managers used to leaving profits in their company.
GILTI and Subpart F: tax before you take the money
Subpart F targets certain passive and mobile income (interest, dividends, royalties, some related-party income), taxing the US shareholder on it immediately. GILTI — Global Intangible Low-Taxed Income — is broader, sweeping in much of a CFC's active business profit above a routine return on tangible assets, and likewise taxing the US owner currently. For a profitable UK consultancy or services company, GILTI can mean US tax on retained profits each year, layered on top of UK corporation tax.
There are reliefs that often soften the blow — the high-tax exclusion, foreign tax credits for UK corporation tax paid, and the section 962 election to be taxed at corporate rates with a credit — and for many UK companies these reduce the GILTI hit to little or nothing because UK corporation tax is relatively high. But the analysis is genuinely complex, and getting it wrong is costly in both tax and penalties.
The $10,000 penalty (and worse)
Form 5471 carries a $10,000 penalty for each form not filed (or filed substantially incomplete) for each annual accounting period. If the failure continues after the IRS notifies you, additional penalties of up to $50,000 per form can apply, and there can be a reduction in your foreign tax credits. Because the penalty is per form and per year, an owner who has not filed for several years can face tens of thousands of dollars in exposure — even if no actual tax was due. This is why Form 5471 compliance is treated so seriously by cross-border advisers.
It interacts with how you pay yourself
The way you extract money from your UK company — salary, dividends, or leaving profits in — all interacts with the US rules. Salary is wages for US purposes; dividends from the company are taxable to you; and retained profits may still be taxed currently under GILTI. The UK-efficient strategy of a small salary plus dividends, common for British company directors, does not neatly map onto the US system, so the optimal remuneration mix for a US owner of a UK company is often different from a purely UK-driven plan. Modelling both sides together is essential.
Don't forget the related filings
Owning a foreign company rarely comes alone. Your company's bank accounts may push you over the FBAR threshold if you have signature authority, GILTI is reported on Form 8992, and the section 962 election and foreign tax credits bring their own forms. The business may also create US filing obligations of its own in some structures. Form 5471 is the centrepiece, but it sits within a cluster of related disclosures that need to be handled together to stay compliant.
What if you have not been filing?
Many Americans discover the Form 5471 requirement years after incorporating, having filed personal returns but never the company information return. If that is you, the good news is there are catch-up routes. Where the wider problem is unfiled or under-filed US returns, the IRS Streamlined Filing Procedures can bring you current — including the missing 5471s — and can mitigate the penalties for those who qualify as non-wilful. Acting before the IRS contacts you is far better than waiting, because the streamlined penalty relief is generally not available once you are under examination.
Smaller stakes and partnerships
Form 5471 is not only for sole owners. If you hold 10% or more of a UK company alongside business partners, you can still have a filing obligation, and the category you fall into depends on the ownership split and whether US persons together control the company. Holding shares through a UK partnership or via family members can also bring 'constructive ownership' rules into play, attributing others' shares to you. If you have any meaningful stake in a UK company, it is worth checking your position rather than assuming a minority holding is exempt.
Plan the structure, not just the form
For a US person, the decision to trade through a UK limited company should be made with the US consequences in view, not as an afterthought. Sometimes a company is still the right answer; sometimes operating as a sole trader (and using the US self-employment rules and the Totalization Agreement) is simpler. Where a company is used, the GILTI position, remuneration strategy and Form 5471 compliance should be designed together from the start. A US/UK specialist can tell you whether your UK company helps or hurts on the US side before the next filing season.
