Cross-border tax planning is the proactive discipline of structuring your income, assets, and affairs to minimise tax across both the US and UK — before obligations crystallise, not after. Reactive compliance is necessary; strategic planning is how high-net-worth individuals and international businesses preserve wealth across jurisdictions.
At a glance — US–UK cross-border tax planning. Cross-border planning means reviewing your position under both the US and UK tax systems before you act — moving country, selling assets, drawing a pension, receiving stock awards or investing — so that both returns are filed consistently and reliefs such as the Foreign Tax Credit, the Foreign Earned Income Exclusion and the US–UK tax treaty are applied correctly.
- Who it is for: Americans living in the UK, UK nationals with US ties, and anyone moving between the two countries.
- What you receive: a written summary of your US and UK filing position, the issues identified, and the forms and deadlines involved.
- Scope: we advise on tax only — we do not recommend investment or pension products.
- Getting started: send us a short enquiry describing your plans and all your sources of income.
- Not a US person but receive US income? See our W-8BEN guide for UK residents.
Our cross-border planning advisory goes well beyond compliance. We model outcomes, compare strategies, and implement structures that are built to withstand scrutiny from both the IRS and HMRC.
Who Benefits From Cross-Border Planning
- US citizens or dual nationals planning to relocate between the US and UK
- High-income expats with investment portfolios in both countries
- Business owners with entities in multiple jurisdictions
- Individuals approaching retirement with pension assets in both countries
- Families with inheritance and estate planning considerations across borders
- Senior executives receiving stock options, RSUs, or carried interest
Core Planning Areas
Residency & Domicile Planning
Residency and domicile status determine which country taxes you, and on what basis. We analyse the UK Statutory Residence Test, the IRS substantial presence test, and the tie-breaker provisions of the US-UK Tax Treaty to ensure you are taxed where it is most advantageous and that your position is defensible under both regimes.
Pre-Departure & Arrival Planning
The year of arrival or departure creates critical planning windows. Triggering events — pension rollovers, asset sales, trust distributions — should be timed around your residency status to minimise tax exposure. Missing these windows is permanent and costly.
Investment Structure Planning
The tax treatment of investments differs dramatically between the US and UK. UK ISAs are tax-free in the UK but may be treated as PFICs under US law (Form 8621), creating punitive treatment. We review your investment portfolio and advise on structures that are efficient under both regimes.
Pension & Retirement Planning
US 401(k)s, IRAs, UK SIPPs, workplace pensions, and the State Pension all have cross-border implications. The US-UK Tax Treaty contains specific pension articles that we leverage to ensure your retirement assets are taxed appropriately — and that distributions are planned in a tax-efficient sequence.
Foreign Tax Credit & FEIE Optimisation
The choice between the Foreign Earned Income Exclusion and the Foreign Tax Credit — and whether to combine them — can alter your lifetime US tax bill by tens of thousands of dollars. We model the optimal strategy for your specific income mix and country of residence.
Capital Gains Planning
Timing asset disposals around your residency status, the UK’s CGT annual exempt amount, and the US-UK Treaty’s capital gains provisions can produce materially different outcomes. We advise on timing, entity choice, and the interaction between CGT and US capital gains rates.
Forms Relevant to Cross-Border Planning
- Form 2555 — FEIE election and calculation
- Form 1116 — Foreign Tax Credit computation across income categories
- Form 8833 — Treaty-based return position disclosures
- Form 8621 — PFIC elections (QEF or mark-to-market) to prevent punitive default tax
- Form 3520 — For planning involving foreign trusts or gifts
- SA109 — UK residence and remittance basis election
- Form 8938 / FinCEN 114 — Ongoing disclosure of foreign assets
US-UK Tax Treaty: A Planning Tool
The 2001 US-UK Tax Treaty (and its protocols) is a cornerstone of cross-border planning. Its key planning provisions include:
- Pension article: generally protects UK pension growth from current US tax
- Government service article: exempts certain government-employment income
- Capital gains article: coordinates which country taxes disposals
- Limitation on benefits: careful planning required to ensure treaty positions are supportable
- Tie-breaker provisions: for individuals resident in both countries under domestic law
Typical US–UK Situations We Plan For
- Moving from the US to the UK — timing of arrival, split-year treatment, and what to do with US accounts and retirement plans. Moving to the UK guide.
- UK pensions and SIPPs — how contributions, growth and withdrawals are treated in each country and when treaty positions need disclosing. UK pension guide · SIPP guide.
- ISAs and UK funds — UK tax-free wrappers that are taxable in the US, and UK funds that can be PFICs. ISA guide · PFIC guide.
- RSUs and share options — sourcing of equity income across work days in each country. RSU guide.
- Selling UK property or shares — UK and US capital gains rules differ, including on a main home. UK capital gains guide.
- Giving up US citizenship or a green card — exit tax and final filing requirements. Exit tax guide.
How to Start
- Send us an enquiry describing what you are planning and all your sources of income in every country.
- We confirm the scope of the review and give you a fee quote before any work begins.
- After onboarding, we review your position and give you a written summary, and we can then prepare the related US and UK returns.
Prefer to talk it through first? Paid consultations are available from £350 for individuals and £550 for businesses.
Frequently Asked Questions
When is the best time to start cross-border planning?
Ideally before you move or before any major financial event. Pre-departure planning — reviewing investments, timing asset sales, pension decisions — can save substantial amounts that cannot be recovered retrospectively. That said, it is never too late to optimise your ongoing position.
Does having a US and UK advisor mean I am covered?
Having separate advisors in each country without coordination is a common and costly gap. US and UK tax rules interact in ways that require joint expertise. We provide both in a single relationship.
Is cross-border planning separate from tax return preparation?
It can be either. Many clients start with a planning review before a move or transaction, then have us prepare the US and UK returns that follow, so the advice and the filings match.
Do you recommend investments or pension products?
No. We are a tax firm: we explain how the US and UK tax rules apply to the options you are considering. Product recommendations should come from a regulated financial adviser.
Related Services & Resources
Start planning before the tax year ends. Book a strategic cross-border planning consultation.