Estate Planning for Cross-Border HNW Families: What You Must Get Right

Why cross-border estate planning is in a different category

Estate planning for a family based in a single jurisdiction is complex enough — navigating inheritance tax, structuring ownership of assets, writing wills that work, establishing trusts, planning for the care of dependents, and managing the succession of a business. For a family whose members, assets and advisers are distributed across multiple countries, the complexity multiplies in ways that are genuinely difficult to manage without specialist help.

The fundamental challenge is that each jurisdiction has its own legal system governing succession, its own tax rules on inheritances and gifts, its own rules on the recognition of foreign wills and trusts, and its own requirements for what is legally enforceable. A will that is perfectly valid in England may not be automatically recognised in France, Monaco or the UAE. A trust structure that is highly effective in Jersey may create unexpected tax complications for a US citizen beneficiary. An asset held in a BVI company may be treated entirely differently for succession purposes than an equivalent asset held personally.

Getting cross-border estate planning right requires not only specialists in each relevant jurisdiction but someone who coordinates across all of them — seeing how the decisions in one country interact with the requirements in another.

The domicile question for UK-origin families

For families of UK origin, the single most important concept in cross-border estate planning is domicile. The UK taxes inheritance on the basis of domicile, not residence — which means that an individual who is UK-domiciled is subject to UK inheritance tax on their worldwide assets at forty percent above the nil-rate band, regardless of where they live, where their assets are held, or how long they have been physically absent from the UK.

This is frequently misunderstood. Many people believe that by moving to Dubai or Monaco — and genuinely living there, not just maintaining a letterbox address — they have resolved their UK inheritance tax exposure. In most cases, they have not. Domicile is a legal concept that relates to an individual's permanent home — the country to which they would return if they had no reason to be anywhere else. For a UK-born individual who grew up in England, built a family and career in England, and has UK domicile by origin, establishing a non-UK domicile of choice requires demonstrating a clear, documented intention to permanently reside in another country with no intention of returning to the UK. This is a higher bar than simply spending the majority of your time abroad.

The practical implication is that many UK-origin families relocating to Dubai or Monaco continue to have significant UK IHT exposure on their worldwide assets for years after their physical departure — sometimes permanently, if the domicile change is not properly managed.

Wills and succession across jurisdictions

A common and dangerous assumption is that a single will, written in one jurisdiction, is sufficient to govern the succession of assets across multiple countries. In practice, the proper management of a cross-border estate typically requires separate wills in each relevant jurisdiction — a UK will for UK assets, a UAE will for UAE assets, a Monaco will for Monaco assets — coordinated to ensure they do not conflict with each other or inadvertently revoke each other.

The rules on what constitutes a valid will vary between jurisdictions. Many civil law countries — France and Monaco among them — have forced heirship rules that require a minimum share of the estate to pass to direct descendants, regardless of what the deceased's will provides. These rules can conflict directly with a common law will that gives the testator complete freedom to direct assets where they choose.

The EU Succession Regulation — which allows EU citizens to elect for the law of their nationality to govern their succession — provides a useful tool for UK-origin individuals with assets in EU countries, though the UK's departure from the EU has complicated this for British nationals.

Trust structures in cross-border planning

Trusts are one of the most powerful tools in cross-border estate planning — but their effectiveness depends entirely on the jurisdictions involved and the specific structure of the trust. A discretionary trust established in a well-regarded common law jurisdiction — Jersey, Guernsey, Cayman, BVI — can provide genuine protection for non-UK assets from UK IHT for a non-UK-domiciled individual, can facilitate efficient succession without probate, and can provide asset protection against future claims.

The complications arise when trust assets, trustees, settlors and beneficiaries span different legal systems. A US beneficiary of a UK trust triggers reporting requirements under the PFIC and grantor trust rules. A French beneficiary may face French succession tax on distributions. A trust established before an individual becomes UK-domiciled may be treated differently from one established afterward.

Lifetime giving and the seven-year rule

For UK-domiciled individuals, lifetime giving remains one of the most effective tools for reducing the eventual IHT liability. Gifts that survive seven years from the date they are made fall outside the estate for IHT purposes — the so-called seven-year rule. Gifts within seven years are potentially exempt transfers and are brought back into the estate on a tapering basis.

The practical implication is that the most effective IHT planning begins well before the eventual date of death — which means beginning it as soon as the exposure is significant, rather than waiting until health issues make it urgent. For cross-border families, the interaction between UK lifetime giving rules and the rules of the other relevant jurisdictions needs careful management.

How Atrium coordinates estate planning

Atrium's estate and succession planning capability is delivered through the tax and legal spoke — ICAEW-aligned, cross-border by design. The relationship manager holds the household brief and coordinates between UK tax advisers, local legal counsel in Monaco, UAE legal advisers and trust administrators in the relevant offshore jurisdictions. The goal is an integrated succession plan that works across all relevant jurisdictions simultaneously — not a series of plans that may conflict at the margins.