Does a single-member US LLC file Form 5471 for its UK company?

Not in its own name if it is disregarded. A single-member LLC that has not elected corporate status is ignored for federal income tax purposes, so the owner is treated as holding the UK shares directly. The owner files Form 5471, usually as a Category 4 filer where they control the company, and attaches it to their Form 1040. If the owner is a US corporation, it attaches the form to its Form 1120.

If my LLC is taxed as a partnership, do the members also have to file Form 5471?

Possibly. The LLC is a domestic partnership and files Form 5471 with its Form 1065. Members owning 10% or more through attribution meet Category 4 or 5 definitions themselves. They may be excused under the constructive ownership exception if the LLC files a complete return covering their information, or they can be included in a joint return and attach the item H statement and Schedule P to their own returns.

Should I check both Category 4 and Category 5a on Form 5471?

No. The IRS instructions for item B say that if you satisfy the requirements of both Category 4 and Category 5a, you check only the Category 4 box and leave the Category 5a box blank. A US owner or LLC that controls more than 50% of a UK Ltd will normally meet both definitions, so Category 4 is the only box checked, although all schedules required for the filer's position must still be completed.

Can a UK private limited company be treated as something other than a corporation for US tax?

Yes. Only the UK public limited company is a per se corporation under the US entity classification regulations. A private limited company is an eligible entity that is a corporation by default because all members have limited liability, but it can elect disregarded or partnership status on Form 8832. After such an election, Form 8858 or Form 8865 replaces Form 5471. The election has wider US and UK consequences and should be modelled first.

Does HMRC treat a US LLC as transparent after the Anson case?

Generally no. After the Supreme Court decision in Anson in 2015, HMRC confirmed in Revenue and Customs Brief 15 (2015) that it would continue to treat US LLCs as companies, regarding Anson as specific to its facts. Claims by UK-resident individuals for double taxation relief are considered case by case. This can create a mismatch where the US taxes a member on income as it arises and the UK taxes a later distribution.

What is the penalty if our LLC never filed Form 5471 for the UK company?

Under section 6038 the IRS instructions set a $10,000 penalty for each annual accounting period of each foreign corporation, with a further $10,000 for each 30-day period after 90 days from an IRS notice, capped at $50,000 additional. Foreign tax credits can also be reduced. Separately, section 6501(c)(8) keeps the assessment period for the related return open until three years after the missing information is furnished.

Form 5471 for a UK Company Owned Through a US LLC

Form 5471 is still required when a US person holds a UK private limited company through a US LLC, but the LLC's US tax classification decides who files it and which return it rides on. If the LLC is a disregarded single-member LLC, the owner files Form 5471 with their own Form 1040 as if they held the UK shares directly. If the LLC is taxed as a partnership, the LLC itself is a US person and generally files Form 5471 with its Form 1065, and its members may have their own filing positions. If the LLC has elected to be taxed as a corporation, the LLC files Form 5471 with its Form 1120 or Form 1120-S.

That is the short answer. The detail matters because the structure is common among US founders who set up a UK trading company, US investors who took a controlling stake in a UK Ltd through an existing holding LLC, and family owners who pooled their shares in a Delaware or Wyoming LLC for governance reasons. In the returns we prepare, the most expensive mistake in this structure is not a technical error on a schedule. It is the LLC filing nothing at all, because each member assumes the UK accountant, the LLC's bookkeeper or another member has it covered. This guide walks through each classification, the Category 4 and Category 5 rules, the aggregate treatment of domestic partnerships for income inclusions, the penalties, and what HMRC makes of the same structure.

What is Form 5471 and why does a US LLC not make it go away?

Form 5471 is the IRS information return of US persons with respect to certain foreign corporations. It reports the foreign company's ownership, income statement, balance sheet, earnings and profits, related-party transactions and, for controlled foreign corporations, the figures that drive subpart F and tested income inclusions. The IRS instructions at https://www.irs.gov/instructions/i5471 say to attach Form 5471 to your income tax return or, if applicable, the partnership or exempt organization return, and file both by the due date including extensions.

The instructions define a US person, for Category 4 and Category 5 purposes, to include a citizen or resident of the United States, a domestic partnership and a domestic corporation. A US LLC is not a separate category of taxpayer at all. For federal tax purposes it is either disregarded, a partnership or a corporation, and the Form 5471 obligation attaches to whichever person the tax law recognises as the owner of the UK shares. Putting an LLC between you and the UK company therefore changes the name on the form, not whether the form exists.

Two filer categories do most of the work in owner-managed UK companies:

Category 4: a US person who had control of the foreign corporation during its annual accounting period. Control means owning stock with more than 50% of the total combined voting power, or more than 50% of the total value of all classes of stock.
Category 5: a US person who was a US shareholder of a controlled foreign corporation (CFC) and owned that stock on the last day in the year it was a CFC. A US shareholder owns, directly, indirectly or constructively, 10% or more of the vote or value. A CFC is a foreign corporation more than 50% owned, by vote or value, by US shareholders.
Category 5a is the default Category 5 type. Categories 5b and 5c are narrower relief categories for foreign-controlled CFCs and rarely apply to a UK Ltd owned by a US LLC.
Categories 2 and 3 can also be triggered in the year the LLC acquires the UK shares or the UK company is formed, because they cover officers, directors and 10% acquirers of foreign stock.

One rule catches people in controlled structures. The item B instructions say that if you satisfy the requirements of both Category 4 and Category 5a, you check only the Category 4 box and leave the Category 5a box blank. A 100% owner of a UK Ltd is therefore a Category 4 filer on the face of the form, not a filer in both boxes, even though the Category 5a requirements are also met.

Is the UK company a corporation for US tax purposes in the first place?

Before deciding who files Form 5471, confirm that the UK entity is a corporation for US purposes. The entity classification regulations list certain foreign entities as per se corporations that can never elect out. For the United Kingdom, the list at https://www.law.cornell.edu/cfr/text/26/301.7701-2 names the Public Limited Company. A UK plc is therefore always a corporation for US tax purposes and always a Form 5471 entity.

A UK private limited company, the familiar Ltd, is not on that list. It is an eligible entity. Under the default rules at https://www.law.cornell.edu/cfr/text/26/301.7701-3, a foreign eligible entity is an association, meaning a corporation, if all members have limited liability. Because every shareholder of a Ltd has limited liability, a Ltd is a corporation by default and Form 5471 applies. Some guides online state that a UK Ltd can never be treated as anything other than a corporation. That is not what the regulations say, and it matters for planning.

A Ltd can elect a different US classification on Form 8832. With a single owner, including a single-member US LLC, it can elect to be disregarded, and with two or more owners it can elect partnership status. After a disregarded election, the owner reports the UK company on Form 8858 rather than Form 5471, and after a partnership election Form 8865 becomes the relevant information return. The regulations limit the effective date of an election to no more than 75 days before filing, and generally bar another change within the following sixty months. An election on an existing Ltd is also treated as a deemed liquidation or restructuring for US purposes, so it is a transaction to model rather than a box to tick. The rest of this guide assumes the Ltd keeps its default corporate status, which is by far the most common position in the structures we see.

Who files Form 5471 under each LLC classification?

This decision list is the part most competitor guides skip. It maps the LLC's classification to the person who signs, the return that carries the form, and the category that usually applies where the UK Ltd is wholly owned.

Single-member LLC, disregarded (default for a one-owner US LLC): the LLC is ignored for federal income tax purposes, so the individual owner is treated as holding the UK shares directly. The owner is the filer, usually Category 4 for a controlling stake, and Form 5471 attaches to the owner's Form 1040.
Single-member LLC owned by a US corporation, disregarded: the corporate parent is treated as the owner and files Form 5471 with its Form 1120.
Multi-member LLC taxed as a partnership (default for two or more owners): the LLC is a domestic partnership and therefore a US person. It files Form 5471, typically as a Category 4 filer where it controls the Ltd, attached to Form 1065. Members who are US shareholders through attribution have their own positions, covered below.
LLC that elected C corporation status on Form 8832: the LLC is a domestic corporation. It files Form 5471 with Form 1120. Members generally do not file unless another category reaches them directly.
LLC that elected S corporation status: the LLC files Form 5471 with Form 1120-S. S corporations share much of the aggregate treatment described below for inclusion purposes, so shareholders need the CFC information to report their own shares.
Any classification, dormant UK company: the IRS allows a summary filing under Rev. Proc. 92-70 for a dormant foreign corporation, completing only page 1 with the required label. The filer is the same person as above.

The first point to verify is the LLC's actual classification, not what the members believe it is. We regularly see LLCs that filed a Form 8832 or Form 2553 years ago that nobody remembers, and single-member LLCs that became multi-member when a spouse or a second investor was admitted, silently switching from disregarded to partnership status. The Form 5471 filer changes with it.

How does Form 5471 work when the LLC is a disregarded entity?

A single-member LLC that is not a corporation is disregarded as an entity separate from its owner under the regulations at https://www.law.cornell.edu/cfr/text/26/301.7701-2. For Form 5471 purposes, that means the US individual is treated as owning the UK shares directly. The individual completes Form 5471 in their own name and attaches it to their Form 1040, reporting a 100% direct holding if the LLC owns all of the UK shares.

In practice, three points come up repeatedly in these returns. First, the Ltd's share register shows the LLC, not the individual, and the Form 5471 needs to reflect the legal chain accurately while reporting the tax owner as the filer. Second, the disregarded LLC does not file its own federal income tax return, so there is no separate return to hang the form on and no reason for anyone at the LLC level to think about it. Third, the individual's subpart F and tested income inclusions flow directly onto their Form 1040, so the Form 5471 figures and the inclusion computations have to reconcile on the same return.

Who files Form 5471 when the LLC is taxed as a partnership?

A multi-member LLC that has not elected corporate status is a partnership for US tax purposes. Because the instructions at https://www.irs.gov/instructions/i5471 list a domestic partnership as a US person for Category 4 and Category 5, the LLC itself is a filer. Where it owns more than 50% of the UK Ltd, it is a Category 4 filer, checks only the Category 4 box, and attaches Form 5471 to its Form 1065.

The members are not automatically off the hook. Under the constructive ownership rules, stock owned by a partnership is treated as owned proportionately by its partners. A member with a 60% interest in an LLC that owns 100% of the Ltd is treated as owning 60% of the Ltd, which is control, so that member also meets the Category 4 definition. A member with 40% is a 10% US shareholder of a CFC and meets the Category 5a definition.

The instructions provide two routes that often remove the need for members to file separate complete forms:

Constructive ownership exception: a Category 4 or Category 5 filer does not have to file if it owns no direct interest in the foreign corporation, is required to furnish the information solely because of constructive ownership from another US person, and that other US person files Form 5471 reporting all of the information required of the member. No statement is required on the member's return to claim this exception.
Multiple filers of same information: one person may file Form 5471 for others if it has the same or greater filing requirements. A Category 5 filer may file jointly with a Category 4 filer. Every person listed in item H of the joint return must attach a statement to their own income tax return with the information described in the item H instructions, and certain categories, including Category 4 and 5a, must also complete a separate Schedule P and attach it to that statement.

Which route applies depends on what each member needs to report for their own income inclusions, and that is where the partnership rules below matter. The safe working assumption is that the LLC files a complete Form 5471 and each member's return documents how that member's own obligation is satisfied.

How do the aggregate rules for domestic partnerships change the inclusions?

Final regulations under section 958 changed how a domestic partnership is treated when it owns a CFC. Under Treas. Reg. 1.958-1(d), published at https://www.law.cornell.edu/cfr/text/26/1.958-1, for purposes of sections 951, 951A and 956(a) a domestic partnership is not treated as owning stock of a foreign corporation within the meaning of section 958(a). Instead, the stock is treated in the same way as stock owned by a foreign partnership, which means it is treated as owned proportionately by the partners. The rules apply to taxable years of foreign corporations beginning on or after 25 January 2022.

In plain terms, a US LLC taxed as a partnership is a pass-through for the income inclusions. The subpart F and tested income inclusions from the UK Ltd are computed at the level of each member who is a US shareholder, not at the partnership level. A member below the 10% US shareholder threshold does not take an inclusion under these rules merely because the partnership itself would have been a US shareholder.

The same regulation lists purposes for which the aggregate treatment does not apply, including determining whether a person is a US shareholder and whether a foreign corporation is a CFC. So the LLC still counts as a US shareholder for testing CFC status, the UK Ltd is still a CFC because the LLC owns more than 50%, and the LLC is still a Form 5471 filer. What changes is who takes the income into their return. That split, CFC status tested at the partnership, inclusions computed at the partner, is why the partnership's Form 5471 and the Schedule K-3 information it gives members have to be prepared together. A partnership Form 5471 that is technically complete but leaves members without the per-member figures they need is a filing that fails in practice.

Federal legislation enacted in July 2025 also amended parts of the CFC regime, including rules on CFC tax years and pro rata shares. The December 2025 revision of the instructions flags these changes, and the current revision of the form and instructions at https://www.irs.gov/forms-pubs/about-form-5471 should be used for each year being filed rather than a prior year's template.

What happens when the LLC has elected corporate status?

An LLC that elected C corporation status on Form 8832 is a domestic corporation. It is the US shareholder, it is the Category 4 filer where it controls the Ltd, and Form 5471 attaches to its Form 1120. The members are shareholders of a US corporation and, in the ordinary case, have no Form 5471 obligation of their own for the UK Ltd, although officers and directors should still check Categories 2 and 3 in years when shares are acquired or the Ltd is formed.

An LLC taxed as an S corporation files Form 5471 with Form 1120-S. For inclusion purposes S corporations are treated much like partnerships under the aggregate rules, so the shareholders need the CFC information to report their own shares. The corporate election also changes the UK analysis, as the HMRC section below explains, which is one reason some owners consider it. It is a decision with wider consequences than Form 5471 and should be modelled across both countries before it is made.

Worked scenario: a two-member LLC owning 100% of a UK Ltd

The following is an illustration only, with assumed facts. Two US citizens, Alex and Jordan, own a Delaware LLC 60% and 40%. The LLC has never filed Form 8832, so it is taxed as a partnership. The LLC owns 100% of the ordinary shares of a UK private limited company that runs a software consultancy from London, with a 31 March year end. Alex lives in New York and Jordan lives in London.

Classification: the UK Ltd is a corporation by default because all its members have limited liability. The LLC is a domestic partnership.
CFC status: tested without the aggregate rule, the LLC is a US shareholder owning 100%, so the Ltd is a CFC.
LLC filing: the LLC has control, meets Category 4 and Category 5a, checks only Category 4, and attaches Form 5471 to its Form 1065 for the year that includes the Ltd's year ending 31 March.
Alex: constructively owns 60%, which is control. Alex meets Category 4 and 5a, and is a US shareholder with inclusions computed on 60% under the aggregate rules.
Jordan: constructively owns 40%, a US shareholder meeting Category 5a, with inclusions computed on 40%. Living in London does not change Jordan's US filing position as a US citizen.
Satisfying the members' obligations: each either relies on the constructive ownership exception because the LLC files a complete return covering their information, or is named in item H of a joint return and attaches the required statement and Schedule P. Either way, the LLC must deliver per-member CFC figures through Schedule K-3 so Alex and Jordan can report their own inclusions.

In this illustration, if the LLC had filed nothing, there would be three missing information obligations, the LLC's and one for each member, not one. And because Jordan is UK resident, the HMRC treatment of the LLC becomes relevant on the UK side too.

What are the penalties for a missed Form 5471?

The penalty section of https://www.irs.gov/instructions/i5471 sets out the section 6038 penalties. A $10,000 penalty applies for each annual accounting period of each foreign corporation for failure to furnish the required information on time. If the failure continues more than 90 days after the IRS mails a notice, an additional $10,000 is charged for each 30-day period or part of one, capped at $50,000 of additional penalty for each failure. The filer may also face a 10% reduction in foreign taxes available for credit, with further reductions if the failure continues.

In an LLC structure, the penalty exposure follows each person who had an obligation. The instructions warn that a person who agrees to have another person file Form 5471 for them may be subject to the penalties if that other person does not file a correct and proper form. The constructive ownership exception protects a member only if the LLC actually files a complete Form 5471.

The limitation period is the second, quieter risk. Under 26 USC 6501(c)(8), reproduced at https://www.law.cornell.edu/uscode/text/26/6501, where information required under section 6038 is not furnished, the time to assess tax on the related return does not expire until three years after the information is furnished. If the failure is due to reasonable cause and not wilful neglect, the extension applies only to the items related to the failure. For a partnership that never filed Form 5471, that can leave its returns, and the flow-through positions of its members, open indefinitely.

What is the most common Form 5471 failure in LLC structures?

The failure we see most often is simple: nobody files. The UK accountant prepares the Ltd's statutory accounts and Company Tax Return and considers the job done, correctly, because UK accountants do not prepare US information returns unless specifically engaged. The US preparer for the LLC receives a Form 1065 file with an investment in a subsidiary on the balance sheet and does not ask what it is. Each member assumes one of the other two advisers is handling the IRS side.

Ask the LLC's US preparer directly whether Form 5471 was attached to each Form 1065, Form 1120 or Form 1040 since the UK company was acquired or formed.
Confirm the LLC's classification history, including any Form 8832 or Form 2553 and any change in the number of members.
Obtain the UK Ltd's statutory accounts for each year so the Form 5471 balance sheet and income statement can be prepared under US principles and translated using the method required by the instructions.
Check the Categories 2 and 3 years, meaning the year the Ltd was formed or acquired and any year officers or directors changed or shares were issued.
Review the members' Forms 1040 for missing CFC inclusions, and the FBAR and Form 8938 positions for UK bank accounts owned by the Ltd, which can reach controlling owners through their ownership interest.

Where years have been missed, the route to compliance depends on the facts, including whether income was also underreported and whether the failures were non-wilful. Late FBARs, where they arise, are filed through FinCEN's BSA E-Filing System with a reason for late filing, or within the Streamlined Filing Compliance Procedures for eligible individuals. The IRS no longer offers a stand-alone delinquent FBAR submission page, so any plan built around it needs revisiting.

How does HMRC treat the US LLC and dividends paid up to it?

On the UK side, the answer turns on a different classification exercise. HMRC's long-standing practice is to treat a US LLC as opaque, meaning a company rather than a transparent entity whose members own its income. In Anson v HMRC in 2015, the UK Supreme Court held on the facts found in that case that a UK-resident member of a Delaware LLC was entitled to the profits as they arose and could claim double taxation relief. HMRC responded in Revenue and Customs Brief 15 (2015), at https://www.gov.uk/government/publications/revenue-and-customs-brief-15-2015-hmrc-response-to-the-supreme-court-decision-in-george-anson-v-hmrc-2015-uksc-44, confirming that it would continue its existing practice of treating US LLCs as companies and regarded the decision as specific to its facts.

HMRC's International Manual at https://www.gov.uk/hmrc-internal-manuals/international-manual/intm180050 sets out its view of Delaware LLCs in light of Anson and says claims for double taxation relief by individuals are considered case by case. It also indicates that where the LLC is a partnership for US purposes, relief may not be available because the same profits are not treated as taxed in both countries in the way the relief requires.

This creates the classic mismatch in our structure. For US purposes, a partnership LLC or disregarded LLC passes CFC inclusions and dividends through to the members. For UK purposes, a dividend paid by the Ltd is paid to a company, the LLC, and a later distribution from the LLC to a UK-resident member is generally a distribution from a company. For US-resident owners with no UK residence, the UK view of the LLC mostly affects the UK company's records and any treaty claims made in the LLC's name. For a UK-resident US citizen member such as Jordan in the scenario, it can mean income taxed in the US as it arises and in the UK when distributed, with a timing and character mismatch that makes relief difficult. HMRC has consulted on reforming the tax treatment of UK-resident members of US LLCs and similar entities, and the position should be checked for the year in question.

What does not change is the UK company's own compliance. The Ltd still files statutory accounts and a confirmation statement at Companies House and a Company Tax Return with HMRC, as described at https://www.gov.uk/company-tax-returns. The US LLC appears in the Ltd's register of members and, where it has significant control, in the register of people with significant control. None of that UK filing satisfies, replaces or reports anything to the IRS.

Form 5471 checklist for LLC-held UK companies

Confirm the UK entity type: a plc is a per se corporation; a Ltd is a corporation by default unless a Form 8832 election was made.
Confirm the US LLC's classification for every year, including changes in membership.
Identify the filer by classification: owner for a disregarded LLC, the LLC for a partnership or corporate LLC.
Where a filer meets Category 4 and Category 5a, check only Category 4.
For partnership LLCs, compute inclusions at member level under Treas. Reg. 1.958-1(d) and deliver per-member figures on Schedule K-3.
Document how each member's own obligation is met: the constructive ownership exception or a joint return with item H statement and Schedule P.
Consider UK residence of any member and the HMRC opaque treatment before any distribution is planned.

Holding a UK company through a US LLC is a sound structure for many US owners, but it multiplies the number of people who can each assume someone else has filed. The right Form 5471 position is a matter of classification, category and the right return, and it should be settled before the first Form 1065 or Form 1040 is filed after the UK company is formed or acquired.