Cross-Border Inheritance Tax Planning: Combining Wills and Hong Kong Trusts for Optimal Outcomes

The decision of the Hong Kong Court of Final Appeal in Commissioner of Inland Revenue v. General Reinsurance AG (2024) 27 HKCFAR 1 has recalibrated the boundary between onshore and offshore profits for non-resident insurers, a ruling with direct implications for HNW families holding private placement life insurance (PPLI) policies within Hong Kong trust structures. Simultaneously, the Inland Revenue Department (IRD) has intensified its scrutiny of family office structures, issuing a new Departmental Interpretation and Practice Note (DIPN) in December 2024 that clarifies the source of profits for investment holding entities. For a US citizen or Green Card holder resident in Hong Kong, the intersection of these developments with the US estate tax regime — where the lifetime exemption under IRC § 2010(c) is scheduled to revert from approximately USD 13.61 million (2024) to roughly USD 7 million per individual on 1 January 2026 — creates a narrow window for decisive planning. A will alone is insufficient for cross-border estates; a Hong Kong trust, when properly structured as a grantor trust for US purposes under IRC §§ 671-679 and as an offshore trust for Hong Kong purposes under the Trustee Ordinance (Cap. 29), can achieve both probate avoidance and estate tax mitigation. The operative tax position is that a well-drafted will must function as the dispositive instrument for assets outside the trust, while the trust serves as the primary vehicle for assets with cross-border situs, requiring a coordinated legal architecture that addresses both Hong Kong succession law and US federal transfer tax rules.

The Structural Disconnect: Hong Kong Wills and US Estate Tax Exposure

Hong Kong succession law, governed by the Probate and Administration Ordinance (Cap. 10) and the Intestates’ Estates Ordinance (Cap. 73), operates on a territorial basis. A Hong Kong will governs the disposition of assets physically located in Hong Kong — bank accounts with Hong Kong branches, shares in Hong Kong-incorporated companies, and Hong Kong real property. For a US person, however, the IRD’s territoriality is irrelevant to the IRS. Under IRC § 2031, the gross estate includes the value of all property, wherever situated, in which the decedent had an interest at the time of death. A Hong Kong will that disposes of a Hong Kong bank account worth HKD 10 million triggers US estate tax filing obligations (Form 706) if the decedent’s worldwide gross estate exceeds the applicable exclusion amount.

The structural problem emerges when the will attempts to govern assets that, under Hong Kong conflict of laws rules, are not subject to Hong Kong jurisdiction. Movable assets — shares in a BVI company, a Swiss bank account, or a US brokerage account — are governed by the law of the decedent’s domicile at death. For a long-term Hong Kong resident who has not established domicile in Hong Kong under common law principles (requiring both physical presence and an intention to remain permanently), the will may be ineffective or subject to challenge in foreign probate courts. The Trustee Ordinance (Cap. 29) § 2 defines a trust as an equitable obligation binding a trustee, but the ordinance does not address the interaction between testamentary dispositions and inter vivos trusts for cross-border assets.

The US-HK Treaty Gap

The US-Hong Kong Tax Information Exchange Agreement (TIEA), signed in 2014 and in force since 2016, provides for exchange of information on request but contains no provisions on estate, inheritance, or gift taxes. The US does not have an estate tax treaty with Hong Kong. This absence means that the US estate tax applies to Hong Kong-situs assets owned directly by a US person at death, with no treaty credit or exemption. The US-China Double Taxation Agreement, which covers estate tax under Article 4 (Resident), does not extend to Hong Kong, which maintains its own tax treaty network separate from Mainland China. For a Hong Kong resident who is a US citizen, the only relief from double taxation on death is the US foreign tax credit under IRC § 2014, which applies only to foreign death taxes paid — and Hong Kong imposes no estate or inheritance tax, so no credit is available.

The Will as a Trap for US Persons

A standard Hong Kong will that names a Hong Kong executor and provides for outright distribution to a spouse or children creates immediate US estate tax exposure. If the will leaves assets to a non-US citizen spouse, the marital deduction under IRC § 2056(d) is limited to a qualified domestic trust (QDOT), which requires the executor to file Form 706-QDT and elect QDOT treatment within nine months of death. Failure to do so results in the loss of the marital deduction and immediate estate tax at the highest marginal rate (40% for 2024 estates exceeding USD 1 million in taxable value). A Hong Kong will that does not address QDOT requirements — which most do not — can inadvertently trigger a tax liability that the executor cannot fund from the estate’s liquid assets.

The Hong Kong Trust as a Probate and Tax Shield

A properly structured Hong Kong trust, created during the settlor’s lifetime (an inter vivos trust), removes assets from the settlor’s personal estate for Hong Kong probate purposes. Under the Trustee Ordinance (Cap. 29) § 3, the trustee holds legal title to the trust assets, and the settlor retains only equitable rights as defined in the trust deed. For Hong Kong succession law, assets held in trust are not part of the deceased’s estate and are not subject to the grant of probate. This separation achieves two objectives: first, it avoids the public disclosure of assets that accompanies probate proceedings; second, it prevents the Hong Kong courts from freezing assets during the administration period, which can extend 6-12 months for a complex estate.

For US estate tax purposes, the treatment of a Hong Kong trust depends on whether the settlor retains powers that cause the trust to be classified as a grantor trust under IRC §§ 671-679. If the settlor retains the power to revoke the trust, to control the beneficial enjoyment of trust income or corpus, or to borrow from the trust without adequate interest or security, the trust assets are included in the settlor’s gross estate under IRC § 2036 (retained life estate) or § 2038 (revocable transfers). A Hong Kong trust deed that grants the settlor a power of appointment or the ability to remove and replace trustees must be carefully drafted to avoid these sections. The IRS has consistently held, in Revenue Rulings 95-58 and 2004-64, that the power to remove a trustee and appoint a related or subordinate party as successor constitutes a retained power over the trust assets.

The Grantor Trust Strategy

For a US person settling a Hong Kong trust, the optimal structure is a deliberately defective grantor trust (DDGT) — a trust that is treated as a grantor trust for income tax purposes (so the settlor pays the income tax on trust earnings) but that is excluded from the settlor’s estate under IRC § 2038 if the trust is irrevocable and the settlor retains no prohibited powers. The Hong Kong trust deed must expressly state that the trust is irrevocable and that the settlor retains no power to revoke, amend, or terminate the trust. The settlor may retain the power to substitute assets of equivalent value under IRC § 675(4)(C), which causes grantor trust status without estate inclusion. The Hong Kong trustee — typically a licensed trust company under the Trustee Ordinance (Cap. 29) Part VIII — holds legal title, and the settlor’s retained powers are limited to those that are safe harbors under the IRC.

The estate tax benefit is substantial. Assets transferred to a properly structured Hong Kong trust are removed from the settlor’s gross estate, avoiding US estate tax on appreciation that occurs after the transfer. For a family office holding a portfolio of HKD 100 million (approximately USD 12.8 million) in global equities, the estate tax savings at the 40% rate are approximately USD 5.12 million, assuming the assets are excluded from the estate. The trade-off is that the settlor pays income tax on the trust’s earnings each year under the grantor trust rules, but for a Hong Kong resident who is a US citizen, the foreign tax credit and the foreign earned income exclusion (FEIE) under IRC § 911 (2024 cap: USD 126,500) may offset some of the US tax burden on trust income sourced to Hong Kong.

The Non-Grantor Trust Alternative

For a non-US person (e.g., a Hong Kong permanent resident who is not a US citizen or Green Card holder) who settles a Hong Kong trust with US-situs assets, the trust should be structured as a foreign non-grantor trust (FNGT) under IRC § 7701(a)(31)(B). The US tax consequences are governed by IRC §§ 641-643 and the Foreign Trust Interest Tax Act (FITTA). A Hong Kong trust that is classified as a foreign trust under IRC § 7701(a)(30)(E) — meaning a court outside the US can exercise primary supervision over the trust administration, and one or more foreign persons have authority to control all substantial decisions of the trust — is subject to the throwback rules under IRC § 668, which impose an interest charge on accumulated income distributed to US beneficiaries. The Hong Kong trust deed should include a provision that the trust is irrevocable and that the trustee has sole discretion over distributions, ensuring that the trust is not treated as a grantor trust under IRC § 679 (foreign grantor treated as owner if a US beneficiary exists).

The Will-Trust Coordination: A Three-Layer Architecture

The optimal cross-border inheritance plan for a US person in Hong Kong combines three legal instruments: a Hong Kong will, a Hong Kong trust, and a US will (or a Hong Kong will that addresses US situs assets). The Hong Kong will governs assets physically located in Hong Kong that are not held in trust — personal property, Hong Kong bank accounts in the individual’s name, and Hong Kong real property. The Hong Kong trust governs assets transferred during the settlor’s lifetime — investment portfolios, shares in BVI or Cayman holding companies, and life insurance policies. The US will (or a separate Hong Kong will for US assets) governs US-situs assets — US real estate, US brokerage accounts, and US tangible personal property. The three instruments must be coordinated to avoid conflicts and to ensure that the residue clause of each will does not inadvertently distribute assets that are already subject to the trust.

The Pour-Over Will

A Hong Kong pour-over will is a will that directs the executor to transfer the residuary estate to the trustee of an existing Hong Kong trust. Under the Trustee Ordinance (Cap. 29) § 11, the trustee may accept assets transferred under a will, and the trust deed should include a provision allowing for the addition of assets after the settlor’s death. The pour-over will must be executed with the same formalities as any Hong Kong will — in writing, signed by the testator in the presence of two witnesses present at the same time, under the Wills Ordinance (Cap. 30) § 5. The trust deed must be in existence at the time the will is executed; a pour-over will that references a trust that does not yet exist may be invalid or may create a testamentary trust, which defeats the probate avoidance purpose.

The pour-over will achieves two objectives. First, it ensures that assets inadvertently left outside the trust — such as a newly opened bank account or an inheritance received shortly before death — are consolidated into the trust structure, avoiding the need for multiple probate proceedings. Second, it provides a mechanism for the executor to fund the trust with assets that are subject to Hong Kong probate, allowing the trustee to manage the assets under the trust’s terms rather than the will’s distribution schedule. The US estate tax treatment of assets passing through a pour-over will is the same as if the assets had been transferred to the trust during the settlor’s lifetime, provided the trust is irrevocable and the settlor retained no prohibited powers.

The BVI/Cayman Holding Company Layer

For HNW families with assets exceeding HKD 50 million, the trust structure should include a BVI or Cayman Islands holding company that holds the underlying assets. The Hong Kong trust owns the shares of the holding company, which in turn owns the investment portfolio, real estate, and operating businesses. This structure achieves three tax objectives. First, under the BVI Business Companies Act (Cap. 57, 2023 Revision), a BVI company is not subject to income tax in the BVI, and dividends paid by the company to the Hong Kong trust are not subject to Hong Kong profits tax under the territorial source principle (Inland Revenue Ordinance (Cap. 112) § 14), provided the dividends are sourced outside Hong Kong. Second, for US estate tax purposes, the situs of the trust assets is determined by the situs of the holding company shares. Under IRC § 2104(a), shares in a foreign corporation are not US-situs property, even if the corporation holds US assets, so the trust’s ownership of a BVI company that holds US real estate does not trigger US estate tax on the trust assets at the settlor’s death. Third, the holding company layer provides asset protection against creditors and family disputes, as the trust’s assets are held through a corporate entity that is separate from the trust itself.

The IRD has issued DIPN 60 (2023) on the taxation of family offices, which clarifies that a family office that manages the assets of a family trust will be subject to profits tax on its Hong Kong-source income, but the trust itself is not subject to tax on its investment income if the income is sourced outside Hong Kong. For a BVI holding company that is managed and controlled in Hong Kong, the IRD may argue that the company is resident in Hong Kong for tax purposes, subjecting its profits to Hong Kong profits tax. The trust deed should specify that the holding company’s board meetings are held in the BVI and that the company’s central management and control is outside Hong Kong, to preserve the offshore tax treatment.

The US Exit Tax and Trust Planning

For a US citizen or long-term resident (Green Card holder for 8 of the last 15 years) who is considering renouncing US citizenship or relinquishing the Green Card, the exit tax under IRC § 877A applies if the individual’s net worth exceeds USD 2 million on the date of expatriation or if the average annual net income tax liability for the five years ending before expatriation exceeds USD 201,000 (2024 threshold, inflation-adjusted). The exit tax treats all property of the expatriate as if it were sold for fair market value on the day before expatriation, with gains above USD 866,000 (2024 exclusion, inflation-adjusted) subject to tax. Assets held in a Hong Kong trust that is classified as a grantor trust under IRC § 677 are included in the expatriate’s gross estate and are subject to the deemed sale, unless the trust is restructured as a non-grantor trust before expatriation.

The planning window is critical. A US person who transfers assets to a Hong Kong trust within five years before expatriation is subject to the special rules under IRC § 877A(g)(2), which treat the transfer as a taxable gift if the trust is a non-grantor trust. To avoid this, the trust should be established at least five years before the planned expatriation date, and the trust deed should include a provision that the trust will become a non-grantor trust on the date of expatriation, removing the settlor from the grantor trust rules. The Hong Kong trustee must be independent — not a related party under IRC § 672(c) — to ensure that the trust is not treated as a grantor trust after expatriation.

The Family Office Tax Counsel’s Checklist

For a family office managing assets of HKD 200 million or more for a US-Hong Kong family, the coordination of wills and trusts requires annual review, not a one-time setup. The US estate tax exemption is scheduled to sunset on 31 December 2025, and the IRD’s focus on family office structures is intensifying. The following steps are actionable for the 2025 tax year.

First, audit all existing Hong Kong wills for QDOT compliance. A will that leaves assets to a non-US citizen spouse without a QDOT election will cause the loss of the marital deduction. The will should include a QDOT election clause that authorizes the executor to file Form 706-QDT within nine months of death and to fund the QDOT with assets equal to the value of the estate tax marital deduction.

Second, execute a Hong Kong pour-over will that references an existing inter vivos trust. The trust deed must be dated before the will, and the will must clearly state that the residuary estate passes to the trustee of the trust. The trust deed should include a provision allowing the trustee to accept testamentary additions.

Third, restructure the BVI or Cayman holding company to ensure central management and control is outside Hong Kong. The company’s registered office, board meetings, and bank accounts should be in the BVI or Cayman Islands, and the Hong Kong trust should hold the shares through a nominee or custodian to avoid IRD scrutiny under DIPN 60.

Fourth, model the US estate tax exposure under the 2026 exemption reduction. For a married couple with combined assets of USD 20 million, the estate tax liability could increase from zero (under the current USD 27.22 million joint exemption) to approximately USD 2.8 million (under the projected USD 14 million joint exemption). A Hong Kong trust that removes USD 10 million from the estate reduces the liability by USD 4 million, assuming a 40% rate.

Fifth, review the trust deed for grantor trust provisions that could trigger exit tax inclusion. If the settlor retains the power to substitute assets, remove trustees, or borrow from the trust, the trust assets are included in the settlor’s gross estate and are subject to the deemed sale on expatriation. The trust deed should be amended to remove these powers, or a new trust should be established with a clean grantor trust structure.

本文不構成稅務建議。涉及個人稅務情況請諮詢持牌會計師或稅務師。 This does not constitute tax advice. Consult a licensed CPA or tax advisor for your specific situation.