US citizens and green-card holders owe US tax on worldwide retirement income, and that reach does not stop at the border of a foreign pension plan. A UK Self-Invested Personal Pension (SIPP), a French Plan d'Épargne Retraite, an Australian superannuation account, a German Rürente — from the Internal Revenue Service's perspective, these are foreign accounts holding US-taxable assets producing US-taxable distributions. The only questions are when the tax falls, at what rate, and whether a treaty rewrites the default. Getting those three answers wrong is how expats end up paying tax twice, paying it early, or filing the wrong forms and drawing five-figure penalties.
This article maps the framework the IRS applies to a foreign pension, contrasts treaty-covered plans against non-treaty ones, explains why employer schemes are treated differently from personal plans, and shows why UK pensions and Australian superannuation — two roughly comparable retirement vehicles in their home countries — end up with wildly different US treatment. Rates and thresholds cited are as of 2026 and should be verified with a qualified cross-border adviser before any distribution or transfer.
The default: worldwide taxation, no automatic exemption
The starting point is unambiguous. The United States taxes its citizens and resident aliens on worldwide income (see United States tax profile), with a top federal marginal rate of 37% for 2026 and preferential long-term capital gains rates of 0%, 15% or 20% depending on income. A 3.8% Net Investment Income Tax may apply above certain MAGI thresholds. State income tax — up to 13.3% in California — is layered on top for residents of taxing states.
Nothing in the Internal Revenue Code treats a foreign pension as automatically exempt or tax-deferred simply because it enjoys deferred status in the country where it sits. A UK pension is not an IRA. An Australian super fund is not a 401(k). Absent a specific treaty article or a domestic Code provision that says otherwise, the general rules apply: contributions may be taxable when made, income inside the plan may be taxable as earned, and distributions are taxable when received. The Foreign Earned Income Exclusion of $132,900 for 2026 does not apply to pension income — the FEIE covers earned income only, and pension distributions are unearned by definition.
Treaty versus non-treaty: the first fork in the road
Whether a bilateral income tax treaty covers the pension is the single most consequential fact in any foreign-pension analysis. The United States has income tax treaties with roughly 65 countries, and most modern treaties include a dedicated pensions article — typically Article 17, 18 or 19. These articles do several things at once:
- Assign primary taxing rights. Most US treaties give the country of residence the primary right to tax private pension distributions, with the source country limited or excluded.
- Preserve tax-deferred growth. Some treaties (notably with the United Kingdom, Canada, Belgium and Germany) contain language that allows the US to respect the tax-deferred character of certain foreign pensions while the participant is a US resident.
- Address lump sums separately. Lump-sum payments from pensions are often carved out of the pensions article and treated under other rules — usually with source-country taxing rights preserved.
Every US tax treaty also contains a saving clause. The saving clause reserves the United States' right to tax its own citizens and residents as if the treaty did not exist, subject to a small list of exceptions. This is why a US citizen living in London cannot simply invoke the US-UK treaty to escape US tax on a UK pension the way a British national living in London can. The exceptions to the saving clause vary treaty by treaty and require careful reading. See the general framework in double taxation treaties explained and the strategic angle in how to use tax treaties.
Where no treaty exists — the Gulf states, most of Southeast Asia outside a handful of jurisdictions, several African countries — the default US rules apply with no relief. A pension from a non-treaty country is taxable on distribution as ordinary income at rates up to 37% federal, with no protection against source-country withholding beyond what the Foreign Tax Credit allows. The FEIE versus foreign tax credit comparison is essential reading before assuming double tax will be relieved.
Employer schemes versus personal plans
The next fork is whether the plan is an employer-sponsored trust or a personal savings vehicle. The distinction matters because two entirely different sections of the Code can apply.
Employer-sponsored foreign pensions
An employer-sponsored foreign pension held in trust is generally analyzed under Internal Revenue Code Section 402(b), which governs non-exempt employees' trusts. Under 402(b), employer contributions may be taxable to the employee in the year contributed if the employee is highly compensated, and earnings inside the trust may be currently taxable to a highly-compensated participant if the plan fails US non-discrimination tests. Most foreign plans fail those tests because they were never designed with US Code in mind. The practical result is that a US-taxable employee may face current-year tax on employer contributions, growth inside the plan, or both — with no offsetting deduction and often no foreign tax credit until distribution.
A treaty can rewrite this. The US-UK treaty, for example, includes provisions that allow qualifying UK employer pension contributions to be treated as if they were contributions to a US-qualified plan, subject to conditions and annual limits that mirror US rules. Similar provisions exist in a handful of other modern treaties. The relief is not automatic and typically requires an affirmative treaty-based return position on Form 8833.
Personal foreign pensions
Personal plans — a UK SIPP, a personal French PER, an Irish PRSA — are usually not held under an employer trust and are often analyzed as foreign grantor trusts or as ordinary foreign investment accounts. This is where the analysis gets dangerous. If the account is characterized as a foreign grantor trust, the participant faces the reporting regime of Forms 3520 and 3520-A, with penalties starting at $10,000 per form per year for late or incomplete filing. If the underlying investments include foreign mutual funds or ETFs, those holdings are typically Passive Foreign Investment Companies subject to the punitive PFIC regime — see PFIC rules for US expats for why this matters. A UK SIPP funded with UK-domiciled OEIC or ETF holdings can generate substantial annual US tax and reporting exposure even when the underlying investments have not been sold.
Lump sums versus periodic payments
Once distribution begins, form matters. The IRS treats periodic pension payments — an annuity, a scheduled monthly draw — as ordinary income taxable in the year received, generally eligible for foreign tax credit relief against source-country withholding. Simple, if not always cheap.
Lump sums are the sharper edge. A single large withdrawal can push the recipient into the top US bracket in the year received, eliminate the marginal benefit of any foreign tax paid over multiple years, and — under many treaties — leave source-country taxing rights intact even where periodic payments would have been residence-only. The UK 25% tax-free lump sum is the most cited example: it is tax-free in the UK, but there is no consensus that it is tax-free in the United States, and the IRS has never formally blessed the position that Article 17(1)(b) of the US-UK treaty exempts it. Practitioners take different views. This is one of the clearest situations in personal international tax where professional review is warranted before any distribution is triggered.
Timing also intersects with the residency question. A distribution taken while the recipient is a non-resident alien of the United States — perhaps in the year before naturalization or after a formal expatriation — can be taxed under fundamentally different rules. The expatriation tax rules can also treat certain deferred compensation and pension amounts as deemed-distributed on the day before renunciation for covered expatriates. Plans to draw a lump sum should be modelled across at least two tax years and under at least two residency scenarios before execution.
Why UK and Australian cases diverge
UK pensions and Australian superannuation look similar from a home-country perspective — both are tax-favoured retirement vehicles with mandatory or heavily incentivised employer contributions, both defer tax on growth, both are core to household retirement planning. From a US tax perspective, they are treated very differently.
UK pensions
The United Kingdom has a comprehensive income tax treaty with the United States that includes a detailed pensions article. UK-source pension income is generally taxable only in the country of residence for treaty purposes, though the saving clause preserves US taxation of US citizens. Employer contributions to a UK registered pension scheme may be treated as contributions to a qualifying plan under the treaty, and growth inside the plan is generally treated as deferred for US purposes so long as the participant remains covered. Distributions are taxable as ordinary US income when received.
The UK context also matters because HMRC's own residency and non-dom landscape shifted substantially from 6 April 2025: the remittance basis was replaced by the four-year Foreign Income and Gains regime, and inheritance tax moved to a residence-based test. See United Kingdom tax profile and UK statutory residence test for the current framework. UK top marginal income tax is 45% (England) and dividend tax runs up to 39.35% — so a returning US expat drawing a UK pension while UK-resident faces a UK tax charge that, under the treaty, will generally be creditable against US tax on the same income.
Australian superannuation
Australia is the sharp contrast. The US-Australia income tax treaty exists and includes a pensions article, but it does not contain the sort of specific superannuation-recognition language found in the US-UK treaty. The result is a long-running unresolved question about how superannuation should be characterised for US tax purposes: is it a foreign grantor trust, a foreign employees' trust under Section 402(b), a treaty pension, or a hybrid?
Different practitioners take different positions, and the IRS has never issued definitive guidance. The stakes are large — Australia's superannuation guarantee rate reached 12% in 2025, and long-tenured Australian residents can hold seven-figure balances. If the fund is treated as a foreign grantor trust, Forms 3520 and 3520-A apply with the associated penalty exposure. If it is treated as an employees' trust under 402(b), current-year income inclusion is possible for highly-compensated participants. If treaty relief applies, the analysis differs again. Australia's top marginal rate is 45% plus a 2% Medicare levy (see Australia tax profile), so double-tax relief through the Foreign Tax Credit is generally available on distribution — but the timing mismatch between Australian tax (mostly on the way in and inside the fund) and US tax (potentially on the way in, inside the fund, and on the way out) is the core problem.
Australian expats with US filing obligations, and US expats resident in Australia with super balances, are among the clearest candidates for specialist cross-border advice. The Australia tax residency exit analysis flags several related complications for those planning to move.
Reporting: the second layer of exposure
US tax on the pension income is only half the compliance picture. Foreign pensions typically trigger some combination of the following:
- FBAR (FinCEN Form 114) if aggregate foreign financial accounts exceed $10,000 at any point in the year.
- Form 8938 under FATCA if thresholds are met — see FBAR and FATCA reporting.
- Forms 3520 and 3520-A if the plan is treated as a foreign trust — penalties start at $10,000 per form.
- Form 8621 for each PFIC held within the plan.
- Form 8833 to disclose any treaty-based return position.
Expats who have missed prior filings often qualify for the IRS Streamlined Filing Compliance Procedures — see streamlined filing for US expats — which can bring returns current without the standard penalty stack, provided the failures were non-wilful.
Social security coordination
Public pensions — state old-age pensions, UK State Pension, Australian Age Pension — sit in a different bucket. They are generally covered by the pensions article of the treaty and by the separate totalization agreements the US has signed with both the UK and Australia. Totalization agreements prevent double social-security contributions and can allow years of foreign coverage to count towards US benefit eligibility. They do not, however, override US income tax on the resulting benefits.
When professional review is essential
Foreign pension analysis is one of the highest-risk areas of expat US tax. Situations that almost always warrant a qualified cross-border adviser — not a generalist CPA — include:
- Any planned lump-sum distribution from a UK pension or foreign employer plan.
- Any Australian superannuation balance above nominal amounts.
- Any personal foreign pension holding foreign mutual funds or ETFs (PFIC exposure).
- Any move that will change residency partway through a tax year with distributions in play.
- Any pension held in a country without a US tax treaty.
- Any covered expatriate planning to renounce US citizenship or long-term green-card status.
Where to go next
Start with the country profiles for the United States, the United Kingdom and Australia to ground the numbers, then read how tax treaties work and how tax residency is determined. For side-by-side rate comparisons, use the TaxAtlas country compare tool. Common questions on cross-border retirement are collected in the FAQ.