US Expat Retirement Accounts: 401(k), IRA, SIPP, and ISA (2026 Guide)

US citizens living abroad face a retirement planning puzzle that neither their US accountant nor their foreign financial advisor fully understands. Your 401(k) still works, but your IRA eligibility may vanish the moment you elect the Foreign Earned Income Exclusion. Your UK SIPP is not a tax-deferred account in the eyes of the IRS. And your UK ISA? Taxable annually in the US, and potentially a PFIC trap. Here's exactly what each account type means for you in 2026.

Your US Accounts While Living Abroad

401(k) and Employer Plans

A 401(k) with a US employer continues to work exactly as it does stateside — you contribute pre-tax (Traditional) or post-tax (Roth 401k), the employer may match, and the account grows tax-deferred for US purposes. Being a non-US resident doesn't change the basic mechanics.

2026 employee deferral limit: $24,500. Catch-up contribution for ages 50–59 and 64+: $8,000 additional (total $32,500). Super catch-up for ages 60–63: $11,250 additional instead of the standard catch-up (total $35,750) — this is new under SECURE 2.0 § 109, effective 2025.¹

Key considerations for expats:

• Non-resident withholding on distributions. When you eventually take distributions as a non-US resident, US withholding tax applies (typically 30%, reducible via tax treaty). If you've returned to the US by then, normal income tax rules apply.
• State income tax. If you haven't properly severed your domicile with a high-tax state, 401(k) distributions may be subject to state income tax even if you're living abroad. Domicile planning matters before you leave.
• Roth 401(k) RMDs eliminated. SECURE 2.0 § 325 eliminated lifetime required minimum distributions from Roth 401(k) accounts starting 2024. You no longer need to roll a Roth 401(k) to Roth IRA to avoid RMDs.

Traditional and Roth IRA: The FEIE Trap

This is where expats most commonly make costly mistakes. IRA contributions are allowed only if you have "includable compensation" — earned income that is not excluded from your US return.²

If you elect the Foreign Earned Income Exclusion (Form 2555) and exclude all of your foreign earned income, your includable compensation is zero. You cannot contribute to a Traditional or Roth IRA that year. This isn't a loophole or a planning opportunity — it's a hard rule under IRC § 219(f)(1), and the IRS enforces it.

Roth IRA: same includable compensation requirement. Additionally, the 2026 MAGI phase-out for single filers is $153,000–$168,000 (joint filers: $242,000–$252,000).¹ High-income expats claiming FTC may still face the income phase-out. Backdoor Roth contributions remain available for those above the phase-out, though they require a deductible Traditional IRA contribution not possible in some scenarios.

RMDs While Living Abroad

Required Minimum Distributions apply to Traditional IRAs, 401(k)s, and most employer plans regardless of your country of residence. Under SECURE 2.0, the RMD beginning age is 73 if you were born between 1951–1959, or 75 if born in 1960 or later.⁴

For US non-residents taking RMDs, the distributions are subject to US income tax. Tax treaty provisions may reduce or eliminate taxation in your country of residence — the US-UK treaty, for example, allocates primary taxing rights on pension income to the country of residence in some circumstances, with the foreign tax credit preventing double taxation on the US side.

UK Pension Accounts (SIPP, Workplace Pension, State Pension)

SIPP and Personal Pensions: §402(b) Treatment

This is where UK-based expats face the most complexity. A UK Self-Invested Personal Pension (SIPP) or stakeholder pension is not a qualified retirement plan under US tax law. The IRS classifies it as a foreign pension trust under IRC § 402(b) — and the tax treatment is fundamentally different from a 401(k):

The UK's 25% tax-free lump sum is one of the most common surprises. In the UK, when you access pension savings you can take 25% (up to £268,275) as a tax-free lump sum. In the US, the saving clause in the US-UK tax treaty explicitly allows the US to tax its citizens as if the treaty didn't exist — meaning that lump sum is ordinary income on your Form 1040. The US-UK treaty Article 17 does not override this for US citizens.⁵

UK State Pension

UK State Pension distributions are generally taxable as ordinary income on your US return. The US-UK tax treaty Article 17(2) provides that "social security benefits and similar payments" paid by one country are taxable only in the country of source — meaning UK State Pension received by a UK resident may be taxable only in the UK. However, the saving clause again overrides this for US citizens: the US retains the right to tax its citizens on that income, with a foreign tax credit available for UK taxes paid.

For US citizens residing outside the UK who receive UK State Pension, the income is taxable in the US and potentially subject to UK withholding as well. The foreign tax credit (Form 1116) is the mechanism that prevents effective double taxation.

UK ISA: No US Tax Advantage

The UK Individual Savings Account (ISA) is a beloved UK savings vehicle — contributions are post-tax, and all growth inside an ISA is tax-free in the UK, with no cap on withdrawals. For a UK resident without US filing obligations, it's excellent.

For a US citizen, the ISA provides no US tax benefit whatsoever. The IRS does not recognize the UK's tax-free treatment:

• Cash ISA: interest is ordinary income on your US return, just like a regular savings account.
• Stocks and Shares ISA holding UK/non-US funds: Most UK-listed ETFs and mutual funds are Passive Foreign Investment Companies (PFICs) under US law. You must file Form 8621 for each one, and the tax treatment on gains is punitive — either ordinary income rates plus an interest charge (§1291 default regime) or mark-to-market treatment with annual recognition of unrealized gains. See the PFIC rules guide for the full analysis.
• Stocks and Shares ISA holding individual equities: Direct ownership of company shares is not a PFIC. If you hold only individual stocks (no funds, no ETFs), you avoid Form 8621 while keeping the ISA structure — but dividends and capital gains are still fully taxable in the US. The ISA is simply a taxable brokerage account from the IRS's perspective.

Other Country Pensions (Brief)

The §402(b) issue is not limited to UK SIPPs. Other countries' pension equivalents present similar challenges:

• Australia Superannuation: Extremely complex. The IRS has not issued definitive guidance on whether Super is a foreign trust or a non-trust foreign pension plan. The US-Australia treaty has a specific pension article, but most tax practitioners treat employer Super contributions as taxable when vested. The 15% concessional tax rate inside Super doesn't translate to US tax deferral. A specialist US-Australia tax advisor is essential.
• Singapore CPF (Central Provident Fund): Employer contributions are generally treated as taxable income when made. CPF has no US treaty equivalent. US citizens working in Singapore should get explicit advice on annual reporting requirements.
• Germany Riester/Rürup: Riester pension contributions are not deductible on a US return. The US-Germany treaty has a pension article, but the saving clause limits its application for US citizens. Rürup (basic pension) may be deductible in some circumstances — but requires specific analysis.
• Canada RRSP/TFSA: The US-Canada treaty explicitly recognizes RRSP tax-deferral, making it one of the few foreign pension vehicles that actually provides US tax benefit. TFSA has no recognition — fully taxable in the US like a UK ISA.

The Strategic Framework for Expat Retirement Planning

US citizens abroad don't have to abandon tax-advantaged retirement savings — but the strategy looks different from purely domestic planning:

1. Consider FTC over FEIE if you're in a high-tax country and want IRA access

The most common mistake: automatically electing FEIE because "I heard it excludes foreign income." If your effective foreign tax rate is near or above the US rate (common in Western Europe), the Foreign Tax Credit likely achieves similar or better results — while preserving your IRA contribution eligibility. Model both scenarios before filing Form 2555.

2. Keep your US brokerage account loaded with US-listed funds

US-domiciled ETFs (Vanguard, iShares, Schwab) are not PFICs. A US brokerage account holding VTI, VXUS, BND — even if you live abroad — is simple, PFIC-free, and avoids most of the foreign-account complexity. This is often the most efficient accumulation vehicle for expats who can't make IRA contributions.

3. Accept the UK pension as a "roughly tax-deferred" vehicle anyway

Even though SIPP employer contributions are technically taxable when vested, many US expats in the UK don't pay US tax on them in practice — because they have sufficient foreign tax credits from UK income tax to offset the US liability. The growth inside the SIPP, while not formally tax-deferred, similarly creates a deferred US tax that gets offset by UK tax on distributions. This isn't guaranteed, and the math varies with income level and treaty position — which is exactly why a specialist is valuable.

4. Coordinate your treaty position before taking SIPP distributions

Whether you're a US citizen resident in the UK, or a US citizen who has left the UK and is now resident elsewhere, the taxing rights on your SIPP distribution differ. Proper treaty analysis before you access your pension — especially for large lump-sum decisions — can prevent significant tax leakage.

Sources

1. IRS — 401(k) limit increases to $24,500 for 2026, IRA limit increases to $7,500. IRS Notice 2025-67. 2026 limits: 401(k) $24,500 deferral; IRA/Roth IRA $7,500 (under 50) / $8,600 (50+); Roth phase-out $153,000–$168,000 (single), $242,000–$252,000 (MFJ). Catch-up $8,000 (50–59, 64+); super catch-up $11,250 (60–63).
2. IRS Publication 590-A — Contributions to Individual Retirement Arrangements (IRAs). IRC § 219(f)(1): "compensation" for IRA purposes means includable compensation — earned income not excluded from gross income. FEIE-excluded income is not includable compensation; IRA contribution forfeited.
3. IRS Rev. Proc. 2025-67 — 2026 FEIE amount. Foreign Earned Income Exclusion for 2026: $132,900. // FEIE 2026 per IRS Rev. Proc. 2025-67.
4. IRS — Required Minimum Distributions FAQs. SECURE 2.0 § 107: RMD age 73 for those born 1951–1959; age 75 for those born 1960 or later. SECURE 2.0 § 325: Roth 401(k) and Roth TSP lifetime RMDs eliminated beginning 2024.
5. IRS Publication 901 — US Tax Treaties. US-UK tax treaty saving clause (Article 1(5)) preserves US right to tax citizens on treaty-exempt income including pension distributions. See also US-UK Treaty Article 17 (pension income). US citizens cannot shelter UK pension lump sums from US tax via the treaty.
6. IRS Publication 54 — Tax Guide for US Citizens and Resident Aliens Abroad. Covers FEIE, FTC, foreign pension reporting, and the interaction between the two mechanisms. Updated for 2026 filing season.
7. IRC § 402(b) — Taxability of Beneficiary of Non-Exempt Trust. Foreign pension trusts that do not qualify as § 401(a) plans are taxed under § 402(b): employer contributions are includable in gross income when vested; employee contributions are post-tax; distributions are taxed accordingly.

Contribution limits and phase-out thresholds reflect 2026 IRS limits per Notice 2025-67. Treaty analysis is US-UK specific; other bilateral treaties differ substantially. SIPP/foreign pension treatment is complex — the interaction of § 402(b), Form 8938, FBAR reporting, and treaty credits requires case-specific analysis. Values verified April 2026.