US-UK tax help for Brits living in America
Become a US tax resident — by Green Card or simply by enough days — and the US taxes your worldwide income, including everything you left behind in the UK: the flat you now let, the workplace pension still growing, the ISA you never closed. Each has a US answer, and most of them are fine when handled deliberately.
At a Glance.
Figures relate to tax year 2025 (US) · 2025-26 (UK)
- Profile
- UK national on a Green Card
- Filings
- Form 1040 + UK rental income
- Reporting
- UK pensions & ISAs
- Focus
- Treaty positions
- Outcome
- No double taxation
What you left in the UK follows you
A let UK property means UK tax through the non-resident landlord rules and US tax on the same rents, with different depreciation and expense rules producing two different profit figures from one tenancy. The gap is reconciled with credits — if both sides are computed correctly.
UK bank accounts, ISAs and investment accounts become foreign accounts for FBAR and FATCA purposes. The paperwork is manageable; missing it is what gets expensive.
Pensions are protected — claim it
The US-UK treaty is unusually generous about pensions: growth inside a UK workplace or personal pension is generally sheltered from current US tax when the position is taken properly. Taken sloppily, the same pension can look like a taxable foreign trust with information-return obligations.
We document the treaty position, file the disclosures that protect it, and keep contributions, growth and eventual withdrawals consistent from year to year.
Residence has edges worth knowing
The substantial presence test counts days across three years, and a visa year that felt temporary can quietly make you a US tax resident. Before a Green Card, there is often a choice about when residence starts; after one, leaving carelessly can trigger the exit tax regime.
Timing a move, a bonus, a property sale or a share vesting around the residence boundary is planning we do before the event — it rarely survives being done after.
Primary sources
Official guidance from the IRS, FinCEN and GOV.UK. Thresholds and rates on those pages are updated annually — check the current tax year before relying on a figure.
Questions, Answered.
Common questions
I still own a rental flat in the UK. Where do I pay tax on it?
Is my UK pension taxed by the US while it grows?
Do my old UK accounts need reporting in the US?
Next Step.
Tell us what you hold — the scope and a fixed fee follow in writing.