Schedule K-1 UK Resident Filers: US Partnership Income on Both Returns

Schedule K-1 UK resident filers: an introduction

If you are a Schedule K-1 UK resident partner in a US partnership, the K-1 drives both your US and UK returns. A Schedule K-1 is the statement a US partnership gives each partner, showing their share of income, deductions, credits and foreign taxes. The difficulty is timing. Many K-1s arrive in September, while your UK return for the year to 5 April is due the following 31 January. This article explains how to report the income in both countries and how to bridge that gap.

This article supports our guide for US and UK founders and executives. That guide covers equity, companies and partnership interests across both tax systems.

Why Schedule K-1 UK resident partners face a timing problem

The US and UK count different years. The partnership reports on the calendar year, while the UK tax year runs from 6 April to 5 April. Therefore, one UK return can need figures from two partnership years. The second of those K-1s may not exist until long after the UK deadline. In our experience, this is the single biggest source of late or estimated UK figures for executives with US fund interests.

What is a Schedule K-1, and when does it arrive?

The K-1 reports your share of the partnership's results for its tax year. It must reach you by the partnership's filing date, which an extension can push to September.

The partnership's own deadline

The Instructions for Form 1065 say a domestic partnership generally files by the 15th day of the third month after its year ends. For a calendar-year partnership, that is 15 March. The same instructions say each partner's Schedule K-1 must be provided by the date the return is required to be filed. However, Form 7004 gives an automatic six-month extension. Many funds use it, so K-1s often arrive in mid-September.

Schedule K-3 and international items

Schedule K-3 is a companion schedule that reports items of international tax relevance. The IRS partner's instructions for Schedule K-3 say Part II shows your share of income by source and category, for the foreign tax credit limit. Part III reports foreign taxes the partnership paid. As a UK resident, you usually need both parts to complete Form 1116. Ask the partnership for a K-3 early, as some do not issue one unless requested.

State tax returns

A partnership that operates in several US states can create state filing duties for its partners. Those depend on each state's rules, not on where you live. Furthermore, Article 2 of the US-UK income tax treaty covers only federal income taxes on the US side. State tax therefore falls outside the treaty. Check the K-1 package for state schedules every year.

How does the UK see your partnership?

The UK classifies each foreign entity as transparent or opaque. That decision changes what you report: your share of profits as they arise, or the distributions you receive.

HMRC's list of US entities

HMRC's International Manual at INTM180030 gives its general view of common foreign entities. For the US, it lists general partnerships, limited partnerships, limited liability partnerships and LLLPs as transparent. It lists the LLC and the S corporation as opaque. A transparent entity is one whose profits are taxed as if the members earned them directly. An opaque entity is taxed like a company, so its members are taxed on what they receive.

The LLC and the Anson case

In 2015 the UK Supreme Court decided Anson v HMRC in favour of an LLC member. However, HMRC's Revenue and Customs Brief 15 (2015) said it would continue to treat US LLCs as companies. It regarded the decision as specific to the facts found in that case. As a result, a UK resident member of a US LLC is usually taxed in the UK on distributions, while the US taxes their share of profits each year.

The 28 October 2026 government response

On 28 October 2026, the government updated its response to the consultation on UK-resident individual members of LLCs and other reverse hybrids. It rejected transparent treatment. Instead, it is minded to provide a new elective credit relief for individual investors, with claims possible from early 2028. A further technical consultation will follow, and the change needs a future Finance Bill. Relief for earlier years is still being considered. Until the law changes, current practice applies.

Checking a specific entity

HMRC's list is a general view, not a ruling on your entity. The manual says its view of a particular entity may differ, and INTM180040 explains how HMRC reaches a definitive view. For example, a limited partnership with unusual terms may need closer review. Therefore, a Schedule K-1 UK resident partner should confirm the classification once, record the reasoning and apply it consistently every year.

How do you meet the 31 January deadline without a K-1?

You file on time using reasonable provisional figures, flag them on the return, then correct them when the K-1 arrives. HMRC's own guidance prefers this to filing late.

Why the UK return needs two K-1s

For trading income, the UK now taxes profits arising in the tax year. HMRC's Business Income Manual at BIM81201 says profits from accounting periods that do not match the tax year are apportioned, by days as the default. A calendar-year partnership therefore feeds two US years into each UK year. For investment partnerships, the timing analysis differs by income type, so confirm the basis with your preparer.

Using provisional figures

HMRC's Self Assessment Manual at SAM121190 covers provisional figures. You tick the provisional box and explain, in the further information box, why you used them and when final figures will follow. HMRC says a return with a provisional figure is not unsatisfactory, though it may open an enquiry. Unreasonable delay in sending the correct figure can lead to a penalty if more tax is due. Consequently, base the estimate on the partnership's quarterly reports, not on guesswork.

Correcting the return later

GOV.UK says you can correct a Self Assessment return within 12 months of the deadline. For the 2025 to 2026 return, due on 31 January 2027, that window runs to 31 January 2028. A K-1 issued in September 2027 therefore arrives in time to amend. If the final figure raises your tax, you pay the difference with interest.

How do the foreign tax credits work between the two returns?

For US-source partnership income, the US taxes first and the UK gives a limited credit. The US then credits the UK tax that remains. The treaty sets the order.

The treaty's special rule for US citizens

Article 24(6) of the treaty applies when the US taxes a citizen who lives in the UK. For US-source income, the UK credits only the US tax a UK resident who is not a citizen would pay. The US then credits the UK tax left after that UK credit. For that purpose, the income is treated as arising in the UK. This re-sourcing rule is what stops the same income being taxed twice.

Matching categories on Form 1116

On the US side, the credit is worked out separately for each category of income. Schedule K-3 Part II provides the source and category information. Without it, your preparer may have to make cautious assumptions that reduce the credit. In addition, excess credits can be carried back one year and forward ten under section 904(c) of the tax code.

Where the LLC creates a mismatch

With an LLC, the US taxes your share of profits when earned, but the UK taxes distributions when paid. The two may fall in different years and be described differently. As a result, matching the US tax to the UK tax is difficult. The proposed credit relief from 2028 is aimed at this mismatch. Meanwhile, each year's position needs careful records of profits, US tax and distributions.

A worked timeline for a Schedule K-1 UK resident partner

Consider a typical case. Rebecca is a US citizen living in Surrey. She holds an interest in a Delaware limited partnership that runs a trading business, and a share of a family US LLC that owns rental property. Both report on the calendar year and extend their returns to September. This is an illustrative example, not a real client.

Her 2025 to 2026 UK return

Her UK return covers 6 April 2025 to 5 April 2026. For the limited partnership, it needs the 2025 K-1, received in September 2026. It also needs profits for January to early April 2026. Those appear on the 2026 K-1, due around September 2027. Rebecca therefore files by 31 January 2027 with a provisional figure for the 2026 slice, based on the partnership's first-quarter report. For the LLC, she reports only the distributions she received in the UK tax year.

Her US returns

On the US side, Rebecca extends her 2025 Form 1040 to 15 October 2026, using the six-month extension for people abroad. Her K-1s arrive in September, leaving a few weeks to finish the return. She pays an estimate by 15 April, because interest runs from then.

Closing the loop

When the 2026 K-1 arrives in September 2027, her preparer replaces the provisional figure and amends the UK return before 31 January 2028. The US credit for 2026 is then worked out on final UK figures. Each Schedule K-1 UK resident year closes about two years after it starts.

The rental LLC follows a different path. The US taxes Rebecca's share of its profits each year, while the UK taxes only the distributions. In years when the LLC keeps its cash, she pays US tax with no matching UK income. In years when it pays out more than it earned, the reverse happens. Consequently, her credits rarely line up neatly, and a Schedule K-1 UK resident member of an LLC is exactly the case the planned 2028 relief is aimed at.

What should you ask the partnership for?

Ask for the K-1 and K-3 together, early estimates, and information that the UK return needs but a US partner would not.

Estimates before the final K-1

Many funds will provide estimated figures in the spring. Ask for them in writing, by quarter if possible. Quarterly figures make the UK apportionment far more accurate.

Distribution statements

For an LLC, the UK return needs the date and amount of each distribution. K-1s show annual totals, which are not enough. Therefore, keep bank records for every payment received.

Fund holdings and carried interest

If you are a fund principal, the K-1 may include carried interest. Our article on carried interest for US persons in the UK covers the special rules. Investment funds may also hold foreign corporations, which can bring extra US forms.

Records to keep each year

Keep every K-1, K-3, estimate and quarterly report, with the date each arrived. Additionally, keep a note of each provisional figure and the amendment that replaced it. HMRC may ask why an estimate was used, and the IRS may ask how a credit was worked out. A Schedule K-1 UK resident file that shows the full trail answers both questions quickly. It also makes the following year's apportionment easier, because the method is already settled.

How US UK Tax Experts can help

US UK Tax Experts prepares US and UK returns for Schedule K-1 UK resident partners from one file. We work out the UK apportionment, set reasonable provisional figures, track the amendments and match the credits on Form 1116. We prepare and file; we do not advise on whether to invest. Our treaty relief service and our guide to the US-UK double taxation treaty explain the credit side in more depth.

Conclusion

For a Schedule K-1 UK resident partner, the main challenge is the calendar. Partnerships report on the calendar year and often extend to September, while the UK return covers a year to 5 April and is due the following January. File on time with flagged provisional figures, then amend within 12 months. Know whether HMRC sees your entity as transparent or opaque, and watch the planned LLC credit relief from 2028. Get the K-3 every year, so the credits match.

Contact us

If you receive K-1s as a UK resident, email hello@usuktaxexperts.com or use our contact form. Tell us which partnerships you hold, how each is structured and which years are filed. We reply within one working day.