Is my SIPP taxed by the US while it grows?

Generally no — the US-UK treaty (Article 18) lets most SIPPs grow tax-deferred in the US for employer-sponsored and certain personal pension types. Some exotic structures need case-by-case analysis.

Do I need to report my SIPP on 3520 or 8938?

8938 usually yes if over threshold. 3520/3520A is contested — recent IRS guidance (Rev. Proc. 2020-17) exempts most employer-sponsored and tax-favoured foreign retirement trusts, but borderline plans may still need filings.

What happens when I take a lump sum?

The 25% UK tax-free lump sum is not automatically tax-free for US purposes. Treaty position under Article 17(2), plan type, and timing all matter — and getting it wrong can trigger ordinary-income treatment in the US on a meaningful amount.

Can I contribute to a SIPP while living in the US?

Contributions are technically possible but often inadvisable — UK tax relief only applies with UK-source earned income, and US treatment of the contribution can be suboptimal. We'd usually recommend pausing UK contributions during US residency.

My workplace pension auto-enrolled me — what now?

Usually fine. Contributions get US treatment analysed (often excludable under the treaty); growth is tax-deferred; distributions are taxed when taken. We map out any ongoing filings and confirm treaty coverage at intake.

◉ Pensions & Investments

UK pension tax planning

How SIPPs and workplace pensions are treated under US law and the US-UK treaty — contributions, growth, and distributions.

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Short answer

UK pensions are not tax-free to the IRS by default. The US–UK treaty lets contributions to a UK employer scheme be deducted and growth be deferred if the position is claimed on Form 8833, and larger schemes and SIPPs can also trigger FBAR and Form 8938 reporting. Lump sums and drawdown are taxed under different treaty articles.

Overview

Why this filing matters

How SIPPs and workplace pensions are treated under US law and the US-UK treaty — contributions, growth, and distributions.

Note — SIPP, workplace pension — US treatment.

◉ Who this is for

•Americans with UK SIPPs
•US persons auto-enrolled into workplace pensions
•Clients approaching UK pension drawdown

✓ What you get

✓US tax treatment analysis
✓Treaty position (Form 8833) where appropriate
✓3520 analysis for certain trust-like arrangements

At a glance

Key forms: 8833 / 3520
Category: Pensions & Investments
Turnaround: 2–3 weeks once documents are complete
Filed by: ACCA-qualified IRS Enrolled Agent

Our approach

Pensions and funds, under the treaty and the code.

UK pensions and investments are where the US–UK treaty does its most useful — and most misunderstood — work. A SIPP may defer US tax under the treaty if the position is claimed properly; an ISA almost never shelters anything from the IRS and often makes things worse by holding PFICs. The difference between the two is a Form 8833 position and a Form 8621 election, not an assumption.

We read each plan and account against both the treaty and the PFIC rules, claim the treaty positions that genuinely apply, and model the PFIC elections (mark-to-market vs QEF) before the gains build up, so your retirement savings are not quietly taxed twice.

Treaty positions on UK pensions claimed on Form 8833 where they apply
ISA and fund holdings tested for PFIC status before gains accumulate
Mark-to-market vs QEF elections modelled rather than defaulted

Private client discussing investments and pensions with an adviser

Our process

How we handle your filing

Four steps from first email to filed return. Fixed fee confirmed in writing before any work begins.

Intake

Send us your situation by email or the enquiry form. We come back with the questions we need answered — every source of income for the year, filing history, accounts and entities — and a tailored document list.

Review

We analyse your position, flag any cross-border risks, and confirm the scope and fixed fee in writing before any work starts.

Prepare

Draft returns and schedules are prepared with plain-English commentary on key positions for your review.

File

You sign electronically; we e-file with the IRS / FinCEN and send you the acceptance confirmations for your records.

Pricing

Fixed fees — no surprises

UK pension analysis: £350 + VAT for a single-plan review; £600 + VAT for multi-plan or pre-retirement drawdown planning. Bundled free with comprehensive tax return engagements.

Prices are indicative starting points and exclude UK VAT, which applies to UK-resident clients only. We quote in writing once we have confirmed every source of income and your filing history for the years involved.

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FAQs

Common questions

Sources

Rules, thresholds and penalties are as published by the IRS and FinCEN at the time of our last review (2026-09-08); always check the current instructions for the year you are filing.

Related services

Others in Pensions & Investments

US 401(k) / IRA — UK tax treatment

How the UK taxes your US retirement accounts during growth, contributions, and distributions — and how the treaty interacts.

Learn more →

ISAs & UK funds (PFIC)

ISAs are not tax-free for US persons. Unit trusts, OEICs, and investment funds inside ISAs are typically PFICs.

Learn more →

Who this is for

Situations where this filing usually applies

Guides from our team on this topic

Ready to get this filed?

Tell us your situation and we’ll reply by email within 2 working days with our questions, then a written scope, fixed fee and document list.

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