US LLC Tax Obligations for UK Residents - Form 5472 and US-UK Treaty Considerations
Summary
UK founders of US LLCs sometimes assume the US-UK treaty handles their US obligations. The treaty does not address information returns. Form 5472 is required.
If you are a UK resident with a US single-member LLC, you have an annual US filing obligation that the US-UK tax treaty does not eliminate. Form 5472, with a Pro Forma 1120, is due April 15 each year. The penalty for missing it is $25,000 per year per LLC under IRC §6038A(d)(1).
Why the US-UK treaty does not remove Form 5472
UK residents who own foreign-owned US single-member LLCs must file Form 5472 annually, regardless of their position under the US-UK tax treaty. The form is an information return, not a tax return, so treaties do not eliminate it. Deadline is April 15 (October 15 with Form 7004 extension). Penalty for non-filing is $25,000 per year. UK Self-Assessment is separate and addresses the UK-side obligation.
Three unfiled years is $75,000. The penalty under IRC §6038A(d)(1) is $25,000 per Form 5472, per year, with no cap on the total: 3 years x 1 form x $25,000 = $75,000. If a second foreign related party also transacted with the LLC, each year needs two forms and the figure doubles to $150,000.
Anson, and why UK treatment of a US LLC cannot be assumed
Form 5472 is an information return required under IRC §6038A. It produces no US tax liability for the LLC by itself. The US-UK Income Tax Treaty addresses:
- Double taxation on cross-border income
- Reduced withholding rates on certain US-source payments to UK residents
- Residency tie-breakers for individuals dual-resident in both countries
- Permanent establishment thresholds for business taxation
The treaty does not address information returns like Form 5472. Treaties generally do not exempt information return obligations because the obligation is informational, not taxational. The IRS uses Form 5472 data to monitor cross-border related-party transactions, an objective unaffected by treaty negotiations on actual tax liability.
This is the point UK founders most often miss. A UK founder who has read the treaty and knows that their LLC is not generating US tax liability still owes Form 5472. The two issues are separate.
Form 5472 does nothing for HMRC, and a UK Self Assessment return does nothing for the IRS. Foreign income reaches HMRC through the SA106 foreign pages filed alongside your SA100, and it has to get there whatever the IRS makes of the entity. The awkward part for UK founders is that the two systems do not agree on what a US LLC is.
| Question | Where it lands for a UK resident |
|---|---|
| Who taxes the income | UK residents are taxed on worldwide income, so US LLC profits generally belong on the UK return. Relief for US tax paid runs through the US-UK treaty and the UK foreign tax credit rules. |
| Where it goes on the return | Foreign income is reported through Self Assessment, on the SA106 foreign pages alongside the main SA100. |
| What HMRC thinks a US LLC is | This is genuinely contested rather than settled. The Supreme Court held in Anson v HMRC [2015] UKSC 44 that the particular Delaware LLC was transparent for UK income tax purposes, reversing HMRC's prior practice of treating US LLCs as opaque. HMRC responded that it regards the decision as specific to its facts and has largely continued its earlier approach, which is precisely why you cannot assume either answer. It turns on the LLC agreement and the facts. |
| Reporting the LLC in the UK | Ownership of a foreign entity can carry its own disclosure consequences depending on the structure and how profits are extracted. |
| Currency | Report in US dollars, while HMRC wants sterling. You will be maintaining two sets of figures for the same transactions, so fix the conversion basis once and keep it. |
The UK classification question is genuinely unsettled, so treat anything you read asserting a clean answer with suspicion, including this. Take it to a UK adviser who has looked at Anson in practice. The US obligation is the settled part.
Two UK-side points are worth naming, because both are routinely applied out of date. Domicile is no longer the connecting factor it was. From 6 April 2025 the remittance basis was abolished and replaced with a residence-based system: new arrivals get relief on foreign income and gains for their first four years of UK residence, provided they were not UK resident in any of the previous ten years. If you were told your US LLC income sat outside UK tax because you were non-domiciled, that advice describes a regime that no longer exists, and the question now is how long you have been UK resident.
National Insurance follows the same classification question as income tax. Class 4 National Insurance is charged on the trading profits of a self-employed individual, so it arises only where the activity is treated as your own trade rather than a company's. That is the Anson question again, in a second tax, and it is decided on the LLC agreement and the facts rather than on the entity being American. Neither point changes anything on the US side: Form 5472 is due either way, and no HMRC treatment of the LLC removes it.
What about UK Ltd-over-US LLC structures?
A common UK structure: a UK Ltd company wholly owns a US LLC. The Ltd holds intellectual property or operating assets; the US LLC handles US-facing operations.
This structure creates two foreign related parties from the US LLC's perspective: the UK Ltd (direct owner) and the individual founder (indirect beneficial owner via the Ltd). The US LLC must file Form 5472 reporting transactions with both, typically via two Forms 5472 or a consolidated Form 5472 with separate Part II sections per Treas. Reg. §1.6038A-2(b).
For UK founders running this structure, accurate identification of related parties is critical. CPA review is typically appropriate for multi-tier structures.
What Form 5472 reports for UK founders
Foreign-owned US single-member LLCs report transactions between the LLC and foreign related parties. For UK founders, the foreign related party is typically the founder personally and possibly any UK companies the founder controls (e.g., a UK Ltd that owns the US LLC).
Reportable transactions include:
- Capital contributions (the founder funding the LLC)
- Distributions (the LLC paying the founder)
- Loans between the founder and the LLC
- Payments for services between the founder and the LLC
- Payments to or from any UK Ltd or other foreign entity the founder controls
Almost every operating UK-founder LLC has at least one reportable transaction per year. The form is filed with a Pro Forma 1120 cover sheet to:
Internal Revenue Service 1973 Rulon White Blvd, M/S 6112 Attn: PIN Unit Ogden, UT 84201
Fax: 855-887-7737.
What about HMRC Self-Assessment?
UK residents have UK-side obligations under HMRC's Self-Assessment regime. US LLC income is generally taxable to the UK resident owner, with US tax (if any) creditable against UK tax under the treaty. The US LLC itself is a "look-through" entity for US tax purposes (disregarded entity) but typically a "transparent" entity for UK tax purposes (the income flows through to the owner).
Filing your UK Self-Assessment does not satisfy Form 5472. Filing Form 5472 does not affect your UK position. They are parallel obligations.
For UK-specific tax questions (Self-Assessment treatment, foreign income reporting, treaty positions), consult a UK tax advisor. The scope of this guide is the US filing only.
The UK founder pattern
UK founders form US LLCs for various reasons: SaaS founders accessing US-based payment processors, e-commerce sellers serving the US market, freelancers with US clients, and digital agencies operating internationally. Formation typically goes through Stripe Atlas, Doola, or Firstbase.
A common assumption among UK founders: the US-UK tax treaty handles cross-border tax issues, so UK residents do not need to engage with US filings beyond what the treaty specifies. This assumption is correct for income tax purposes (the treaty does affect double taxation and reduced withholding) but incorrect for information returns like Form 5472.
Form 5472 now, Self Assessment on its own timetable
If you are a UK resident with a US LLC and have not filed Form 5472, the right action depends on whether the IRS has contacted you. For voluntary catch-up cases, file all unfiled years with a reasonable cause statement under §6664(c). The cornerstone diagnostic is at Missed Form 5472. For the immediate panic action plan, see What to Do Right Now. For multi-year cases, see Filed 5472 Multiple Years Late.
For standard UK-founder cases (single related party, capital contribution at formation, ordinary distributions), filetax.co generates the complete Form 5472 + Pro Forma 1120 packet for $99. UK Ltd-over-US LLC structures or cases with multiple related parties benefit from CPA review.
The IRS's official Form 5472 instructions are at IRS.gov/Form5472.
On the OBBBA 1% remittance excise under IRC 4475, which applies to transfers made after 31 December 2025: it reaches transfers funded by cash, money order or cashier's check, and bank-account, debit and credit funded transfers fall outside it, which covers how almost every founder here moves money.
On BOI reporting: since 26 March 2025 US-formed entities are exempt from the beneficial ownership reporting requirement. It does not affect Form 5472.
What UK owners ask
Does the US-UK treaty exempt me from filing Form 5472?
No. The US-UK Income Tax Treaty addresses tax liability and double taxation. It does not address information returns. Form 5472 is required regardless of treaty position.
My UK Ltd owns the US LLC. Does the LLC still need to file?
Yes. The US LLC files Form 5472 reporting transactions with both the UK Ltd (direct owner) and the individual founder (indirect beneficial owner). This typically means filing two Forms 5472 or a consolidated filing with separate Part II sections.
My LLC has no US-source income. Why do I file?
Form 5472 is an information return, not a tax return. The form is required when reportable transactions occurred regardless of whether any US tax is owed. The §6038A obligation is independent of income tax.
Does HMRC see my US LLC filings?
HMRC and the IRS have information-sharing arrangements under various agreements. The forms you file with the IRS are not directly transmitted to HMRC, but the IRS can share information on request. UK residents should ensure their UK Self-Assessment accurately reflects US LLC income regardless.
Does the BOI exemption apply to UK-owned US LLCs?
Yes. The March 2025 FinCEN interim final rule exempts all US-formed entities from BOI reporting. UK-owned US LLCs (formed in any US state) are no longer required to file BOI reports.
Is my US LLC transparent or opaque for UK tax?
It depends on the LLC agreement and it cannot be assumed either way. Anson v HMRC [2015] UKSC 44 held a particular Delaware LLC transparent for UK income tax purposes, but HMRC treats that decision as specific to its facts and has largely continued its earlier approach. This is a question for a UK adviser reading your operating agreement. It does not affect Form 5472.
Does SA106 cover any of this?
No. SA106 is the foreign pages of a UK Self Assessment return and it reports foreign income to HMRC. Form 5472 reports transactions between your US LLC and its foreign related parties to the IRS. Completing one has no bearing on the other.
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