WEALTH // Navigating Wealth Across Borders: A Guide for US-UK Connected Families
In today’s world of cross-border careers, families, and investments, the idea of “home” is rarely fixed. Nowhere is this more evident than for US–UK connected clients: Americans in Britain, Brits in the States, dual citizens, and even “accidental Americans.” Opportunity comes hand-in-hand with complexity: two tax systems, two legal frameworks, and a maze of financial rules that don’t always align. Success lies in planning holistically to protect wealth, preserve flexibility, and ensure structures support the life you want to live. We spoke with Amy Hill and Swaati Osborne of LGT Wealth Management US to explore how US-UK Connected families can avoid costly missteps and embrace the opportunities of a transatlantic life.
Global mobility has become the new reality for many high-net-worth families. Whether driven by career opportunities, lifestyle choices, or family ties, living across borders brings both freedom and complexity. Few groups face this more acutely than US-UK connected clients, whose lives, assets, and obligations stretch across two of the world’s most scrutinised tax systems.
Who Are US-Connected Clients?
US tax law casts a wide net. The category of “US-connected” reaches far beyond passport holders: it includes green card holders, accidental Americans, beneficiaries of US trusts, students, entrepreneurs relocating for work, and even spouses of US citizens. For these individuals, managing wealth is not simply about investing wisely: it is about structuring life across two systems that rarely align neatly.
Why Global Mobility Has Accelerated
Post-COVID flexibility, Brexit’s reshaping of residency patterns, and the rise of remote work have all spurred more families to live transnationally. At the same time, governments have tightened rules, increased transparency, and introduced more demanding reporting standards. Visa regimes in both the US and UK have grown restrictive, and traditional tax “arbitrage” has become harder to achieve.
As Osborne puts it, “Globally mobile families often hold multiple citizenships and assets across jurisdictions. That makes planning complex, not just about tax, but about lifestyle, legacy, and values.”
Common Misconceptions
Many US-UK clients assume shared language means shared rules. In reality, key differences catch people out:
Pre-arrival planning is essential. Without it, individuals risk double taxation, inefficient investments, or compliance traps.
Tax years differ. The US runs on a calendar year; the UK uses an April-to-April tax year. This mismatch alone can complicate income timing.
Dual filing is required. Americans abroad must continue to file US tax returns, regardless of UK obligations.
Structures don’t always translate. Trusts, LLCs, S-corps, and UK pension wrappers may create unintended liabilities when viewed from the “other side.”
The golden rule: tell your advisers everything, and ensure they communicate across borders.
Property, Pensions, and Planning Pitfalls
Real estate is a recurring flashpoint. In the UK, primary residences usually escape capital gains tax. Not so for US citizens, where gains above a modest allowance can be taxed at 20%. Even mortgages can create “phantom gains” due to currency movements.
Pensions are another minefield. UK pensions are often held in trust structures that US authorities treat differently, creating compliance burdens and unexpected reporting costs.
Estate planning reveals stark contrasts: in the UK, only £325,000 (or £500,000 with residence relief) can pass tax-free before 40% inheritance tax applies. In the US, the lifetime gift and estate allowance is almost $14m per person, due to rise to $15m. Such discrepancies demand careful structuring for families with assets in both countries.
Protecting Wealth Through Life Events
From marriage to inheritance, citizenship can determine outcomes:
Marriage: A Brit married to a US citizen may find property ownership and gifting rules far less straightforward. Prenups executed in one jurisdiction may not automatically carry weight in the other.
Divorce: Jurisdiction shopping is common. The UK is often seen as more favourable, but outcomes depend on how assets are taxed in each spouse’s hands.
Inheritance: Parents must consider the location and citizenship of heirs. A US trust may protect one child but create liabilities for another living in London.
Strategies for Future-Proofing Wealth
In a world of shifting politics and volatile currencies, no plan can be entirely rigid. Hill and Osborne emphasise three principles:
Diversification – across currencies, jurisdictions, and asset classes.
Coordination – ensure lawyers, accountants, and wealth managers talk to each other.
Flexibility – structures should adapt to sudden moves, family changes, or policy shifts.
Cash-flow modelling can help families scenario-plan for inflation spikes, tax reform, or unexpected relocation. “The plan doesn’t need to predict the future,” says Osborne. “It needs to withstand it.”
Acronyms to Know
FATCA (Foreign Account Tax Compliance Act): Requires foreign banks to report US clients’ holdings.
CRS (Common Reporting Standard): The global equivalent of FATCA, driving cross-border transparency.
401(k), IRA, Roth IRA: US retirement accounts, sometimes analogous to UK ISAs and pensions, but treated differently by each system.
Looking Ahead: The Future of Global Mobility
Mobility is here to stay. Hotspots like Italy (with its favourable regime for new residents), Dubai, and parts of Asia are attracting interest. Yet for many, lifestyle factors such as grandchildren, schools, professional opportunities outweigh tax arbitrage.
“Flexibility is the word of the day,” Hill concludes. “But the other golden rule is advice early. Build a team that understands the dual complexities and look at your life holistically. That’s how you protect not just your wealth, but your freedom to live the way you want.”
Global Mobility Checklist for US–UK Connected Clients
Before you move, invest, or restructure, ask yourself:
1. Pre-Arrival & Residency Planning
Have I had pre-arrival tax and legal advice (at least 6–12 months ahead)?
Do I understand how residency will be determined in both the US and UK?
Have I considered the impact of double tax treaties on my income, assets, and reporting?
Am I clear on which jurisdiction will view me as a tax resident?
2. Tax Filing & Compliance
Am I aware I may need to file in both the US and UK?
Do I understand the different tax years (calendar vs April-April)?
Have I identified whether FATCA/CRS reporting applies to me?
Are my accountants and advisers across both jurisdictions communicating?
3. Structures & Investments
Have I reviewed whether my trusts, LLCs, or S-Corps are tax-efficient in both countries?
Are my pensions and retirement accounts compliant and correctly reported?
Do my mutual funds / underlying investments have dual US/UK reporting status?
Am I avoiding inefficient wrappers or products designed for only one system?
4. Real Estate & Property
Have I considered capital gains tax treatment of UK property as a US citizen?
Do I understand the “phantom mortgage” risk from FX movements?
Am I clear whose name property should be in (especially in mixed-nationality marriages)?
If buying property for children (e.g. at university), have I reviewed the tax implications?
5. Marriage, Divorce & Family Planning
Is my prenup or postnup valid in the jurisdiction I live in?
If married to a US/British spouse, do we know how gifts, assets, and property ownership are treated?
In case of divorce, do I know which jurisdiction would apply and how the split would be taxed?
Have I modelled how inheritance or divorce outcomes would look net of tax?
6. Estate & Inheritance Planning
Do I understand the very different allowances (UK £325k vs US ~$14m)?
Have I planned when and how to make gifts (and survival periods)?
If I (or my children) might inherit from a US trust, is it structured optimally for UK residency?
Have I considered insurance or other tools to mitigate estate tax exposure?
7. Currency, Portfolios & Diversification
Am I clear which currency my income needs will be in?
Have I diversified across currencies, jurisdictions, and custodians?
Do I have an FX strategy to protect against swings in USD/GBP?
Is my portfolio efficient for both growth and compliance?
8. Team & Coordination
Do my US and UK advisers (lawyers, accountants, wealth managers) actively communicate?
Am I working with professionals who understand cross-border complexities?
Have I scenario-tested my financial plan (inflation, tax hikes, relocation)?
Is my plan flexible enough to adapt if my circumstances change?
9. Golden Rules
Plan Early – ideally 6–12 months before relocating.
Communicate – tell every adviser about your US/UK connection.
Stay Flexible – avoid rigid structures that can’t move with you.
Keep It Holistic – let values and lifestyle drive decisions, not just tax.
Swaati Osborne | Head of Wealth Planning, LGT Wealth Management US
+44 20 3207 8386
Amy Hill | Wealth Manager, LGT Wealth Management US
+44 20 3207 8385
