The UK exempts your 25% lump sum. The treaty's lump sum rule sits outside the saving-clause carve-out, so the IRS may tax it anyway - with no credit to claim.
A UK pension commencement lump sum is free of UK tax up to the lump sum allowance — but that exemption does not cross the Atlantic. For a US citizen or green card holder, the treaty provision dealing with lump sums sits outside the saving-clause carve-out list, so on the reading HMRC itself records, the IRS can tax the payment notwithstanding the treaty; and because the UK charged nothing, there is usually no foreign tax credit to put against it. The position is genuinely contested among careful advisers, which is why it is so expensive to get wrong.
Since 6 April 2024 the lifetime allowance has gone, replaced by two allowances that cap tax-free lump sums rather than total fund value. GOV.UK puts the headline simply: "You can usually take up to 25% of the amount built up in any pension as a tax-free lump sum," and "The most you can take is £268,275." That cap is the lump sum allowance, and three payment types count against it: a pension commencement lump sum, the tax-free 25% element of an uncrystallised funds pension lump sum (UFPLS), and a stand-alone lump sum.
Above it sits the lump sum and death benefit allowance of £1,073,100, covering wider cases such as a serious ill-health lump sum or certain death benefits; HMRC's technical treatment is at PTM171000. Exceed the allowances and the excess is taxed as income, the provider deducting the charge before payment. Both can be higher with a protected allowance, and pensions already in payment before 6 April 2024 will have used part of them up. Access age matters too: the normal minimum pension age is 55, legislated to rise to 57, with PTM062210 confirming "A new protected pension age will be introduced from 6 April 2028".
The UK exemption is a feature of UK pensions legislation. It tells you what HMRC will charge, and nothing about what the Internal Revenue Code will charge, because the US taxes citizens and green card holders on worldwide income wherever they live. So a US citizen in London asking "is my 25% tax-free?" is really asking two questions: does UK law exempt it — usually yes, within the allowance — and does US law, as modified by the treaty, exempt it? That second question has no clean yes.
Our general guide to US tax on UK pensions and SIPPs covers the wider framework: contributions, growth, ongoing income and reporting. This article deals only with the lump sum, where the treaty argument is sharpest.
Everything turns on the 2001 UK/USA Double Taxation Convention as amended by the 2002 protocol, in force since 31 March 2003.
Article 17(1)(a) is the general rule: "Pensions and other similar remuneration beneficially owned by a resident of a Contracting State … shall be taxable only in that State." A UK-resident retiree's pension is, on its face, taxable only in the UK.
Article 17(1)(b) then does a great deal of work: "Notwithstanding sub-paragraph a) of this paragraph, the amount of any such pension or remuneration … paid from a pension scheme established in the other Contracting State … that would be exempt from taxation in that other State if the beneficial owner were a resident thereof … shall be exempt from taxation in the first mentioned State."
In plain terms, the residence state must respect an exemption the source state would have given. This is the provision practitioners reach for in arguing a UK PCLS should be free of US tax.
Article 17(2) is a separate, overriding rule: "Notwithstanding the provisions of paragraph 1 of this Article, a lump-sum payment derived from a pension scheme established in a Contracting State and beneficially owned by a resident of the other Contracting State shall be taxable only in the first-mentioned State."
Note the opening word. Where 17(2) applies, it displaces paragraph 1 entirely — including paragraph 1(b) — which is what makes the characterisation question below decisive.
Article 1(4) is the saving clause: "Notwithstanding any provision of this Convention except paragraph 5 of this Article, a Contracting State may tax" its residents, and "its citizens by reason of citizenship," "as if this Convention had not come into effect."
That is the hinge. The US may tax its citizens as though there were no treaty — except where Article 1(5) says otherwise. So everything becomes: what is in that list? It is short and closed, and worth stating precisely because it is routinely overstated.
Two observations decide the case. First, Article 17(2) is not on the list — nor is Article 17(1)(a); of the whole of Article 17, only paragraphs 1(b), 3 and 5 are carved out. Second, because limb (b) covers only individuals who are neither citizens nor permanent residents, a US citizen or green card holder cannot use it at all.
HMRC is unusually direct. INTM163160 states that "the US regards the lump-sum provision in paragraph 2 of Article 17 of the UK/US DTA to be an anti-avoidance measure," and that although "paragraph 2 of Article 17 gives exclusive taxation rights over lump sum payments to the State in which the payment arises, this is in effect overridden by paragraph 4 of Article 1." The citizenship limb, it adds, "currently only has effect for the US" because the UK taxes by source or residence, not citizenship.
The live country guidance at DT19853 reaches the same place: Article 1(4) applies to US citizens because Article 17(2) is not listed in Article 1(5), so the US can tax lump sums received by US citizens from UK schemes.
If the payment is not a "lump-sum payment" within Article 17(2), paragraph 1 governs — and 17(1)(b) is protected from the saving clause. Characterisation is therefore the whole argument.
INTM163160 gives HMRC's indicators. A lump sum is "any non-periodic, irregular or abnormal payment of a pension." Then the proportion-of-fund tests:
HMRC also weighs the regularity of payment dates and amounts, whether the payment differs significantly from the member's usual payments, whether it materially reduces the fund and so later payments, and whether a principal purpose is to obtain a treaty benefit. Where payments are irregular it may look across several years for a pattern.
Apply that to a classic PCLS and the facts are uncomfortable. Twenty-five per cent of the fund clears the 20% indicator; it is a one-off; it differs materially from the drawdown payments that follow; and it reduces the fund. On HMRC's own indicators, a conventional PCLS looks like a treaty lump sum.
The competing readings are real, and both deserve stating.
The "17(1)(b) applies" reading. Article 1(5)(a) deliberately preserves 17(1)(b) against the saving clause, and it would be odd to carve out a provision that could never benefit a US citizen. On this reading, a payment from a UK scheme that would be exempt from UK tax in UK-resident hands — which the PCLS is — should be exempt from US tax too. It is the basis on which some Americans have taken the 25% and reported nothing.
The "17(2) governs, so the saving clause bites" reading. Paragraph 2 opens with "Notwithstanding the provisions of paragraph 1," so for a lump sum, paragraph 1 — including 1(b) — is switched off. With 17(2) unprotected by Article 1(5), the US taxes. This is the reading HMRC records as the US position, and the conservative line most cross-border practitioners take.
Structural arguments run both ways. Those favouring exemption say 17(2) was designed for genuinely cross-border payments, and reading it to displace 1(b) for a payment to someone resident in the same state as the scheme stretches it beyond its purpose. Those against point to the absence of any IRS pronouncement blessing the exemption, and the plain fact that the carve-out list omits 17(2). Related reading: withholding tax on cross-border payments.
This is not, in short, a settled exemption of the kind a UK adviser might assume from the words "tax-free". The favourable position requires disclosure and carries real risk of challenge.
Foreign tax credits relieve double taxation by crediting tax actually paid to the other country. If the UK charges nothing on the PCLS — the entire point of the PCLS — there is no UK tax to credit, and the US charge lands unrelieved. The familiar expat intuition that "the UK tax will cover it" fails precisely because the payment is UK tax-free.
Nor does the UK step in. Article 24(6)(a) provides that where the US taxes a US citizen resident in the UK in accordance with paragraph 4 of Article 1, the UK is not required to credit that US tax against income which is not US-source — and a UK lump sum from a UK scheme is not US-source. Both mechanisms switch off at once. Worse, the US charge falls at ordinary graduated rates on the whole amount in a single year, exactly the receipt that pushes a taxpayer into the top bracket, with no general US averaging relief.
If instead of crystallising a large lump sum you draw the pension as periodic income — regular drawdown payments, or an annuity — the analysis shifts in three ways:
The trade-off is blunt: the lump sum route may deliver zero UK tax and a full, unrelieved US charge, while the income route delivers UK tax that is substantially creditable. Which is cheaper depends on marginal rates on both sides, fund size, other income in the year, the mismatch between the UK 5 April and US 31 December year-ends, and whether the taxpayer expects to remain a US person. It must be modelled, not assumed. Phased crystallisations are sometimes proposed to keep payments on the periodic side of HMRC's indicators, but that can equally look engineered, and the treaty's principal-purpose considerations are live.
Reporting obligations are independent of the tax answer, and not optional.
Taking the favourable position and failing to disclose it is the worst of both worlds: the exposure remains, and an undisclosed position is a far weaker place to stand on examination.
Because this question attracts so much commentary, we checked the primary trail. HMRC restructured its USA country guidance on 4 August 2026. The old detailed country pages, including DT19876A (United States of America: Pensions from 2003), were archived and replaced by a consolidated set: DT19850 (convention in force), DT19851 (admissible taxes), DT19852 (treaty summary) and DT19853 (notes). Older citations to the archived pages no longer resolve to live guidance.
What it is not is a change of position. The live DT19853 notes, as updated on 4 August 2026, still state that Article 1(4) applies to US citizens because Article 17(2) is not listed in Article 1(5), so the US can tax lump sums received by US citizens from UK schemes. INTM163160 was published in March 2025 and last amended that same month, and the International Manual's change log records no 2026 amendment to it. Commentary suggesting HMRC has revised its treaty reading appears to concern the opposite direction — UK taxation of lump sums drawn from US schemes such as 401(k)s and IRAs — a different question.
1. Establish your US status precisely — citizen, green card holder, or neither — and your UK residence position for the year.
2. Get the scheme facts in writing: scheme type, whether it is a UK registered pension scheme, the allowance remaining after earlier crystallisations, and any protected allowance.
3. Model both routes in both currencies, full PCLS against phased income, across the UK 5 April and US 31 December year-ends.
4. Decide the treaty position consciously, and check the reporting perimeter — Form 8938, FBAR, any Form 8833 — before filing rather than after.
For a US person with a UK pension approaching the point of taking benefits, this is one of the few genuinely irreversible moves in cross-border tax. The UK exemption is real, the US exposure is real, the argument against it arguable but unsettled — and the reliefs that normally rescue a double charge do not operate here, because one side has charged nothing at all.
We model both routes, document the treaty position taken and the reasoning behind it, and prepare the US and UK returns together so characterisation, timing and reporting line up. Every US filing is reviewed and signed off by a licensed IRS Enrolled Agent who is also ACCA-qualified on the UK side. To settle the position before you instruct your provider, our US-UK tax specialists can help — book a consultation.
General information on the tax treatment of UK pension lump sums for US persons, current at the date of publication. This is not pension, investment or financial advice, and not advice on your own circumstances. The US treatment of a UK pension commencement lump sum is contested, careful advisers take different views, and no IRS pronouncement settles it. Outcomes depend on individual facts — US status, UK residence position, scheme type, allowances remaining, other income, and timing. Take advice before taking a lump sum, because the decision cannot be reversed.