多国居住家庭的IHT筹划策略：如何合法降低跨境遗产税负担

For a family with members living across the UK, Hong Kong, and Australia, the question of inheritance tax is rarely simple. HM Revenue & Customs reported in its 2023-24 annual statistics that UK Inheritance Tax receipts reached a record £7.5 billion, a 4.2% increase from the previous year, driven largely by frozen nil‑rate bands and rising asset values. Yet for multi‑jurisdiction families, the risk is not just a UK tax charge—it is double or even triple taxation on the same estate. The OECD’s 2022 Model Tax Convention on Estates and Inheritances notes that fewer than 20 bilateral estate‑tax treaties exist globally, meaning most cross‑border estates fall back on domestic relief provisions that are often inconsistent. This article sets out the specific strategies available to reduce UK Inheritance Tax exposure for families with assets or members in multiple countries, using anonymised case studies and current legislation.

Understanding Domicile: The Foundation of UK IHT Liability

The UK taxes worldwide assets on a person who is domiciled in the UK, regardless of where they live. Domicile is a common‑law concept distinct from residence or nationality. A person acquires a domicile of origin at birth (usually their father’s domicile) and can acquire a domicile of choice by settling permanently in another country. HMRC’s Inheritance Tax Manual (IHTM13001) states that a person who has been resident in the UK for 15 of the past 20 tax years is deemed domiciled for IHT purposes, even if they never intended to stay permanently. For a family where one parent remains UK‑domiciled while the other is domiciled in Hong Kong, the IHT exposure differs dramatically.

The Deemed Domicile Trap

Mrs A, a Hong Kong‑born British citizen, lived in London for 16 years before relocating to Singapore. Under the deemed domicile rules, she remains UK‑domiciled for IHT until she has been non‑resident for at least three full tax years (s.267(1)(b) Inheritance Tax Act 1984). During this period, her worldwide estate—including a Singapore property and Hong Kong investment portfolio—remains within the UK IHT net. The nil‑rate band of £325,000 (frozen until at least 2028 per the Spring Budget 2024) applies only once. For cross‑border estates, the double taxation relief provisions in s.159 IHTA 1984 may reduce the UK charge by the amount of foreign tax paid, but only if the foreign tax is “similar” to UK IHT—a test that many Asian jurisdictions fail.

Structuring Assets to Break UK IHT Exposure

For multi‑residence families, the most effective strategies involve removing assets from the UK IHT net entirely by changing ownership or the legal situs of the property. Excluded property is a key concept: assets situated outside the UK owned by a person who is not domiciled (and not deemed domiciled) are outside the scope of UK IHT. For a non‑domiciled spouse, holding non‑UK assets in a trust or through a non‑UK company can preserve excluded status even after the settlor becomes deemed domiciled, provided the trust was created before the 15‑year threshold was reached.

Using a Trust for Non‑UK Assets

Mr Y, a Hong Kong permanent resident with a UK‑based business, placed his Hong Kong residential property and Singapore equities into an offshore trust in 2018, before he reached 15 years of UK residence. Under s.48(3) IHTA 1984, property situated outside the UK held in an excluded property trust is not subject to UK IHT, even if the settlor later becomes deemed domiciled. The trust must be irrevocable and the settlor must not retain a benefit—otherwise the gift with reservation rules apply. HMRC’s 2023 Trusts and Estates Newsletter confirmed that the excluded property status of such trusts is not affected by the settlor’s later change of domicile, provided the trust was created before the deemed domicile date.

The Residence Nil‑Rate Band and the Family Home

For families with a UK home, the residence nil‑rate band (RNRB) provides an additional £175,000 allowance per person (2024‑25 rate) on the value of a main residence passed to direct descendants. However, the RNRB is tapered by £1 for every £2 of the estate above £2 million. For a cross‑border family, the UK home is often the only UK‑situs asset, making the RNRB particularly valuable—but only if the home is actually left to children or grandchildren. The downsizing addition (s.8K‑8P IHTA 1984) allows the RNRB to be claimed even if the home was sold before death, provided the proceeds were left to direct descendants.

The Taper Trap for High‑Value Estates

Mr and Mrs Z own a London home valued at £1.8 million and have combined worldwide assets of £3.2 million. Their combined RNRB of £350,000 is tapered by £1 for every £2 over the £2 million threshold, reducing it to £250,000. If they gift the home to their children during their lifetimes, the RNRB is lost entirely unless the gift is a “downsizing” event. A better strategy is to keep the home in the estate and use a deed of variation after the first death to redirect assets to the surviving spouse, thereby preserving the full RNRB for the second death.

Gifting Strategies Across Jurisdictions

Lifetime gifts are a classic IHT reduction tool, but cross‑border families must consider the gift tax or capital gains tax implications in the recipient’s country. The UK’s seven‑year rule (s.7 IHTA 1984) means that gifts made more than seven years before death fall outside the estate, subject to the taper relief for gifts made between three and seven years. For a family where the donee is resident in Australia, the gift may trigger Australian capital gains tax (CGT) on the eventual sale of the asset, as Australia taxes residents on worldwide gains. A UK‑domiciled donor gifting shares in an Australian company to an Australian‑resident child should consider whether the child’s future CGT liability outweighs the UK IHT saving.

The Annual Exemption and Small Gifts

Each individual has an annual IHT exemption of £3,000 (2024‑25), plus a small gifts exemption of £250 per recipient per year. For a couple, this means £6,000 can be gifted each year without any IHT reporting. Over 10 years, that is £60,000 removed from the estate, potentially saving £24,000 in IHT at 40%. For cross‑border families, these gifts can be made in any currency or asset class, provided the donor retains no benefit. Regular gifts out of income (s.21 IHTA 1984) are also exempt, but must be part of a “normal expenditure” pattern—a written record of the pattern is advisable for HMRC scrutiny.

The Role of Life Insurance and Trusts

Life insurance policies written in trust are a common way to provide liquidity for IHT bills without increasing the estate. For a cross‑border family, the policy should be written in a flexible trust that allows the trustees to pay premiums from a non‑UK account, avoiding UK currency controls or reporting. The payout is then outside the estate and can be used by executors to settle the IHT liability within the six‑month payment window. HMRC charges interest on late IHT payments at 7.75% (from 6 December 2024), so liquidity planning is critical.

Cross‑Border Policy Structuring

Mrs X, a UK‑domiciled widow with a Hong Kong investment property, took out a whole‑of‑life policy on her life, written in a discretionary trust with her two children as beneficiaries. The policy was issued by a Hong Kong insurer and premiums were paid from her Hong Kong bank account. Because the policy is situated in Hong Kong (the location of the insurer’s register), it is treated as a non‑UK asset. As Mrs X is UK‑domiciled, the policy is still within the IHT net—but because it is held in trust, the payout goes to the children directly, bypassing probate and providing immediate cash for the IHT due on the Hong Kong property.

FAQ

Q1: Can I avoid UK IHT by simply moving to Hong Kong permanently?

Moving to Hong Kong and severing all UK ties can change your domicile of choice, but the deemed domicile rules mean you remain UK‑domiciled for IHT for three full tax years after leaving. If you have been UK‑resident for 15 of the past 20 years, you are deemed domiciled during that period regardless of your intention. After the three‑year tail, if you have acquired a domicile of choice in Hong Kong (by permanent residence, no intention to return, and strong ties), your non‑UK assets become excluded property. However, your UK‑situs assets remain taxable. A full domicile change typically takes at least 5–7 years of demonstrable non‑UK living.

Q2: How does the UK double taxation treaty with Hong Kong affect IHT?

The UK and Hong Kong have no bilateral estate tax treaty. The only relief available is unilateral double taxation relief under s.159 IHTA 1984, which allows a credit for foreign tax paid on the same asset, but only if the foreign tax is “similar” to UK IHT. Hong Kong has no inheritance tax, so no credit is available. For assets in jurisdictions with a tax, such as Australia (which has no federal IHT but state‑level death duties in some cases), the credit is limited to the lower of the UK tax and the foreign tax. Always check the specific treaty—if one exists—before relying on unilateral relief.

Q3: What is the seven‑year rule for gifts, and does it apply to non‑UK assets?

Yes, the seven‑year rule applies to all assets owned by a UK‑domiciled person, regardless of where the asset is situated. A gift of a Hong Kong apartment made today will only fall outside the estate if the donor survives seven years. If death occurs within three years, the full 40% IHT is due. Between three and seven years, taper relief reduces the tax rate but does not remove the asset from the estate. The recipient’s domicile is irrelevant; only the donor’s status matters. For non‑domiciled donors, only UK‑situs gifts are caught.

References

• HM Revenue & Customs. 2024. Inheritance Tax Statistics 2023-24.
• OECD. 2022. Model Tax Convention on Estates and Inheritances.
• HM Revenue & Customs. 2024. Inheritance Tax Manual (IHTM13001, IHTM27001).
• UK Government. 2024. Spring Budget 2024: Inheritance Tax Nil‑Rate Band Freeze.
• HM Revenue & Customs. 2023. Trusts and Estates Newsletter (Issue 9).