Form 5472 for UK-resident founders

If you are a UK-resident founder with a Delaware or Wyoming LLC, the US side of your compliance is roughly the same as it would be from Bangalore, Lagos, or anywhere else: the IRS does not care which flag is on your passport, only whether you are a non-US person owning 25% or more of a US entity. What does change is the way the US filing lines up with your UK self-assessment, your personal tax residency, and (for some founders) the UK’s remittance-basis rules.

This guide walks through the practical US-side filing, the UK side at a high level, and the specific places where the two sides touch.

US side

Your US LLC’s annual Form 5472 + accompanying 1120 is the baseline. For a single-member LLC that has not elected corporate taxation, the 1120 is a pro-forma cover with the header “Foreign-owned U.S. DE” and the schedules left blank — the actual information return is the 5472. For a US LLC that has filed Form 8832 to be taxed as a C-corporation, you file a real 1120 with the 5472 attached, and e-filing is available.

Nothing specific to being UK-resident changes the US form itself. The ID you report in the owner section is your UK Unique Taxpayer Reference (UTR) as the foreign tax identification number, or your National Insurance number if you do not have a UTR yet. Both are acceptable foreign-TIN substitutes; the IRS does not require a US TIN for a non-US owner.

Due dates

• Form 5472 + 1120: 15 April for a calendar-year entity, extendable to 15 October with Form 7004 filed on or before the original date.
• Delaware LLC annual tax: $300, due 1 June.
• Delaware franchise tax + annual report (C-corp only): $50 report fee plus the franchise tax, due 1 March.

The 1 June Delaware deadline is a surprise to many UK founders because Companies House conditions you to think about “the September filing window” — but Delaware runs on its own calendar.

UK side at a high level

If you are a UK tax resident, HMRC generally expects you to report your worldwide income — including profits from a US LLC — on your Self-Assessment return. The specific line of your SA return depends on the US entity’s classification:

• US LLC taxed as a disregarded entity (default for an SMLLC): HMRC traditionally has treated this as a transparent entity broadly similar to a UK partnership; your share of the LLC’s profit flows up to you personally and is taxed on your Self-Assessment. However, HMRC’s treatment of US LLCs has shifted over the years, and there is case law (notably Anson v HMRC) that pushes the other way. For material amounts, confirm with a UK tax adviser.
• US LLC that elected C-corp taxation (or a US Inc): HMRC treats this as opaque — a corporation. You are not taxed on the LLC’s profits as they accrue; you are taxed on dividends or salary when the US entity actually pays them out to you personally.

Both treatments interact with the US filings, but not by changing what you file in the US. The US 5472 obligation is the same. What changes is the way the UK side reads the US entity.

Deadlines on the UK side

• Online Self-Assessment: 31 January after the end of the tax year (UK tax year runs 6 April to 5 April).
• Paper Self-Assessment: 31 October after the end of the tax year.

These are entirely independent of the US 15 April deadline. BorderFile does not file your UK Self-Assessment — we coordinate with a UK partner adviser under the annual compliance plan.

Treaty considerations

The US–UK tax treaty is one of the better-articulated treaties the US has with any country. For a founder whose only US connection is a passive US LLC, the treaty is rarely load-bearing — the LLC’s profits either flow through to you (disregarded case) or stay inside a US entity until paid out (C-corp case). But the treaty becomes relevant if any of the following are true:

• You spend material time in the US and might be a US tax resident under the substantial-presence test.
• Your US company pays dividends or interest to you personally; treaty rates on withholding tax may apply (typically reduced from the statutory 30%).
• You hold a cross-border services or licensing arrangement with the US company (e.g. you provide services from the UK, the US entity pays you).

A treaty position usually requires a disclosure on the US side (Form 8833) and may require Form W-8BEN with a treaty claim on file with the US company’s payer. These are expert-desk engagements; the standard 5472 service does not include treaty analysis.

The non-dom and remittance-basis angle

UK founders on the remittance basis (either as a current non-dom under the rules in force before 6 April 2025 or under the newly introduced residence-based regime from 6 April 2025 onwards) sometimes assume that their US LLC’s profits are only taxable in the UK if remitted. This is partly true and partly a trap.

Where HMRC treats the LLC as transparent, the profits are foreign source and may fall under the remittance basis — but only if they are kept outside the UK and never used to acquire UK-situated assets or services. In practice this is hard to maintain for a founder who lives in the UK and uses the US entity to fund personal UK spending.

The newly introduced regime (post-6 April 2025) tightens the picture further. If this applies to you, do not rely on an old adviser’s remittance-basis assumptions — the rules changed.

Common UK-specific mistakes

1. Treating “UK Ltd via a US LLC” as the same filing. A UK Ltd that owns a US LLC is a different fact pattern. The 5472 identifies the UK Ltd as the owner; UK Ltd’s own filing position (CT600, HMRC CT return) is unaffected by the US 5472 itself.
2. Using your UK home address as the US correspondence address. The IRS can route correspondence here; a US registered-agent address is a much better default.
3. Forgetting the UK Self-Assessment reporting of foreign holdings. The US 5472 does not satisfy any UK obligation; your UK adviser needs to be told the US LLC exists.
4. Assuming the US and UK deadlines align. They do not. 15 April (US), 31 January (UK online SA). Plan both.
5. Treaty positions taken without documentation. If you want the US–UK treaty’s reduced withholding on US-source dividends to apply, you need the W-8BEN with treaty claim on file at the payer, not just in your mental model.

What BorderFile does and does not do for UK founders

We do:

• Prepare and file Form 5472 + the accompanying 1120 for your US entity, every year.
• Keep your Delaware (or Wyoming) annual filings on the calendar.
• Issue a 1099-NEC to any US-person contractors the US entity paid.
• Coordinate with a vetted UK accountant partner on your Self-Assessment, under the annual-compliance plan.

We do not:

• File your UK Self-Assessment ourselves.
• Give UK tax-residency advice.
• Issue formal treaty-position memos as part of the standard 5472 engagement (those go through the expert desk).

In one sentence

For UK founders, the US filing is the same as for any other non-US owner; the complexity is on the UK side, where the LLC’s HMRC classification, your personal residency, and the Self-Assessment deadline all live independently of the US calendar.

Not tax advice; see the disclaimer.