Form 5472 for UK founders of US LLCs

UK tax residents who own a US single-member LLC have a clean, well-trodden filing path: the LLC files Form 5472 with the IRS each year ($25k penalty if missed), and the owner reports the LLC on the UK self-assessment return as a transparent foreign entity — no double tax because the LLC has no US tax of its own and HMRC treats it as a flow-through for the UK side. The US-UK tax treaty doesn't change Form 5472 obligations, but it does eliminate most of the income-side concerns founders worry about.

This guide is specifically for UK residents (or UK citizens non-resident in the UK) running a Wyoming / Delaware / NM LLC. The Form 5472 rules are the same as for any non-US owner; the UK side is what differs.

The two sides of the picture

US side — Form 5472 + pro forma Form 1120

Identical to every other foreign-owned single-member LLC.

• Filed annually by April 15 for a calendar-year LLC.
• Faxed to the IRS Ogden PIN Unit.
• Required even with $0 revenue — your initial capital contribution counts as a reportable transaction.
• $25,000 per-form penalty for failure to file.
• No US income tax due — the LLC is disregarded, and a UK-resident owner with no US-source ECI has no US personal return either.

UK side — HMRC and the self-assessment

HMRC treats a US LLC as a transparent entity for UK tax purposes in most cases, so the LLC's profit is taxed in the owner's hands as it arises, similar to a UK sole trader. HMRC has traditionally taken a case-by-case view on LLC opacity; the 2015 Anson Supreme Court decision pushed the treatment toward transparent. As of current guidance most UK accountants treat a single-member US LLC owned by a UK resident as transparent.

Practical consequences for a UK-resident owner:

• The LLC's net profit flows onto your UK self-assessment (SA100) as foreign self-employment / foreign trading income.
• UK income tax + Class 2/4 National Insurance apply at UK rates.
• No US tax to credit against (the LLC paid none), so no double-tax mechanics.
• UK self-assessment is due 31 January following the tax year — six weeks before the US Form 5472 deadline of April 15.

What the US-UK tax treaty does and doesn't do

The US-UK tax treaty (1975, amended 2001) prevents double taxation on cross-border income — primarily by allocating taxing rights and offering tax credits when both sides tax the same item. For a UK-resident owner of a disregarded US LLC with no US-source income:

• The treaty doesn't reduce or waive the Form 5472 information return obligation. 5472 is an information return, not a tax — treaties don't override §6038A.
• The treaty doesn't change the $25,000 penalty exposure.
• The treaty does protect against the owner being subject to US income tax on the LLC's profits, provided the owner has no US permanent establishment.

Translation: file Form 5472 anyway. The treaty isn't a way out of it.

Practical gotchas for UK-resident LLC owners

The EIN application — fax to the IRS

UK addresses, UK passports, and UK NI numbers all work fine on Form SS-4. Field 7b takes the literal text "Foreign" — don't write your UK NINO or UTR there. Full SS-4 walkthrough here.

UK banking for the LLC

Mercury, Wise Business, and Relay all accept UK-resident owners of US LLCs. You don't need to visit the US to open the account.

FBAR — does the LLC owe one?

Only if the LLC has foreign (non-US) financial accounts whose aggregate balance exceeded $10,000 at any point during the year — and only if the LLC is treated as a US person for FBAR. A US LLC is a US person for FBAR regardless of who owns it, so if your LLC holds money in a UK bank account over $10k at any point, the LLC owes an FBAR (FinCEN Form 114). Most LLCs bank entirely in the US (Mercury/Wise USD), in which case there's no FBAR.

VAT and UK corporation tax

The LLC is not a UK company — it doesn't register for UK corporation tax, and unless you have a UK permanent establishment for its activities, it doesn't owe UK CT either. UK VAT is a separate question: if you sell digital services to UK consumers above the registration threshold, you may need to register the LLC for UK VAT under non-established taxable person rules.

Conservative summary for UK founders

• The US side is Form 5472 + pro forma 1120 — same as any non-US owner. Snapfile handles this for $89.
• The UK side is self-assessment SA100 + (probably) foreign trading income — speak to a UK accountant familiar with US LLCs.
• The US-UK treaty doesn't waive Form 5472. File it.
• No double tax in the typical case — the LLC pays no US tax and the UK taxes the same profit once via your SA.
• FBAR only applies if the LLC banks outside the US over $10k.

Snapfile is not a UK accountant — for the SA100 side, find a UK CPA familiar with US disregarded entities. For the US Form 5472 side, we do exactly one thing well: 12 questions, $89, faxed to Ogden.