UK pensions under US rules: where the treaty helps and where it does not

Article 18(1) is one of the few treaty provisions listed as surviving the saving clause for citizens, which is why it works at all for a US passport holder. Properly claimed, it shelters growth inside employer schemes and SIPPs from annual US taxation.

Contributions are a different paragraph and a different answer. The relief for contributions sits in Article 18(2), and the saving clause carve-out for that one reaches only individuals who are not citizens of the taxing state — so a US citizen cannot lean on it against the IRS. Growth and contributions have to be argued separately, not as one package.

Claimed is the operative word: the position should be established on the return, consistently, rather than assumed. And the scheme still appears on the FBAR and often Form 8938 — treaty protection is about tax, not disclosure.

Employer contributions and personal contributions are looked at differently, and relief on the US side does not automatically mirror the UK's generous treatment. Large employer contributions in particular can raise current-tax questions the payslip never hints at.

SIPPs add a second layer: a self-invested pension holding UK retail funds raises PFIC questions inside the wrapper. The conservative reading keeps the treaty shelter over the whole structure, but fund choice inside a SIPP still deserves the same US-aware eye as any other account.

Twenty-five percent of a UK pension can typically be taken free of UK tax. That relief is a feature of UK law, not of the treaty, and the US does not simply follow it. Taking a lump sum while US-resident, without modelling it first, is one of the most expensive unforced errors in cross-border tax.

Timing relative to a move matters more than people expect: the same withdrawal can produce materially different outcomes depending on which side of a residence change it falls. Drawdown order across UK pensions, IRAs and 401(k)s is a genuine planning lever — which is an argument for sequencing the retirement, not just reacting to it.

This is the distinction that catches most people: the treaty argument is about who taxes the growth, and it says nothing about who has to be told the account exists. Those run on entirely separate rules.

A SIPP or personal pension is reportable on the FBAR in the ordinary way once the aggregate of your non-US accounts passes $10,000 at any point in the year. Some employer schemes sit in a greyer area, where the conservative answer is to report - disclosure carries no tax and the form costs nothing.

Form 8938 runs on its own higher thresholds, $200,000 at year end for a single filer living abroad, with a separate any-time test. Our guide to Form 8938 and the FBAR sets out how the two regimes differ.

Once payments start, the question changes from who taxes the growth to who taxes the income, and the treaty allocates that separately again. Periodic payments and lump sums are not treated identically, which is why the shape of a withdrawal matters as much as its size.

Our guide to treaty Article 17 covers how pension income is allocated between the two countries. The practical point for planning is that the same pot can produce materially different outcomes depending on how and when it is drawn.

Where withdrawals are taxed in both countries, foreign tax credits reconcile most of the overlap, but they work on tax actually paid and they sit in income categories that do not mix freely. A year with a large withdrawal and little other foreign income can strand credits that a different sequence would have used.

The UK State Pension is a separate question from a workplace or personal scheme, and it interacts with the totalization agreement rather than with the pension articles alone. Contributions made in one country can count toward entitlement in the other.

Our guides to the totalization agreement and National Insurance for Americans cover how the contribution side works. The agreement exists mainly to stop the same earnings being charged to social security twice.

Entitlement and taxation are different questions again. Qualifying for a State Pension says nothing about which country taxes it once it is in payment, and that allocation follows the treaty rather than the agreement.

Almost everything here is cheaper to plan than to unwind, and the lump sum in particular is close to impossible to fix afterwards.

Take an illustrative example: an American who has worked in London for two decades, with a workplace pension, an old employer scheme and a SIPP holding three UK funds. He is approaching the age at which he could take a lump sum.

The growth across all three is sheltered under the treaty provided the position is claimed properly on each return. All three are reportable regardless, and the SIPP holdings raise their own questions inside the wrapper that the conservative reading answers but does not make disappear.

The lump sum is the decision worth money. Taken in the wrong year, or on the wrong side of a move back to the United States, the same withdrawal produces a materially different outcome - which is an argument for sequencing a retirement rather than reacting to one.

The first is bundling the treaty paragraphs together. Growth and contributions sit in different paragraphs with different saving-clause treatment, and an argument that works for one does not carry to the other.

The second is assuming treaty protection removes the reporting. It does not, and the forms run on balances rather than on tax.

The third is taking the lump sum first and asking afterwards. It is the single most expensive unforced error we see in this area, and the only one that is genuinely difficult to remediate.