Cross-Border Wealth Transfer Tax: Using Hong Kong Trusts for Multi-Generational Asset Planning

The 2026 US tax year marks a critical inflection point for cross-border wealth transfer planning. The scheduled sunset of key provisions under the Tax Cuts and Jobs Act (TCJA) on 31 December 2025 will halve the federal estate and gift tax exemption from approximately USD 13.61 million per individual to a pre-2018 base of roughly USD 5 million (adjusted for inflation), compressing the window for high-net-worth families to shift assets out of US situs without triggering immediate gift tax. Simultaneously, Hong Kong’s Inland Revenue Department (IRD) has intensified its focus on trust structures under the revised tax residence rules for trustees, codified in the Inland Revenue (Amendment) (Taxation of Trusts) Ordinance 2023. For US citizens and green card holders domiciled in Hong Kong, the interplay between these two regimes—Hong Kong’s territorial source principle and the US’s worldwide estate and gift tax system—creates a narrow planning corridor. The central question for family offices and UHNW individuals is whether a Hong Kong trust, properly structured with non-US situs assets and compliant with both IRC § 2036 (retained interests) and the IRD’s new trustee-residence test, can achieve genuine multi-generational wealth transfer without triggering a US tax event at the settlor’s death or during the trust’s administration. This analysis examines the mechanics, treaty implications, and structural pitfalls of using Hong Kong trusts as a vehicle for cross-border wealth transfer, drawing on the US-Hong Kong Tax Information Exchange Agreement (TIEA) and the US-China Double Taxation Agreement (DTA) as applied to Hong Kong residents.

The 2025-2026 Window: US Estate Tax Exemption Sunset and Its Impact on Hong Kong Trusts

The TCJA’s temporary doubling of the estate and gift tax exemption expires on 31 December 2025. For a married couple who are both US citizens living in Hong Kong, the combined exemption drops from approximately USD 27.22 million to roughly USD 12 million (based on 2024 inflation-adjusted projections). This contraction directly affects the viability of transferring assets into a Hong Kong trust without incurring gift tax liability. Under IRC § 2503, a gift to a trust is a completed gift for US tax purposes only if the settlor retains no dominion or control over the property. A Hong Kong trust that grants the settlor a power to revoke or amend the trust—common in certain discretionary structures—would fail this test, rendering the transfer an incomplete gift and pulling the assets back into the settlor’s US gross estate under IRC § 2038.

The operative position for US citizens in Hong Kong is that any transfer of US situs assets (e.g., shares in a Delaware corporation, US real estate, or US mutual funds) into a Hong Kong trust before 31 December 2025 should be treated as a taxable gift at the time of transfer, valued at fair market value, and sheltered only by the remaining exemption. After the sunset, the same transfer would face a 40% gift tax rate on amounts exceeding the lower exemption. The IRD does not levy gift tax, but the US does—and the US-Hong Kong TIEA (Article 4, Exchange of Information) permits the IRS to request trust documentation from the IRD if the trust holds US situs assets or has a US beneficiary.

The Trust Structure: Hong Kong Trustee vs. US Grantor Trust Rules

A Hong Kong trust is not automatically a foreign grantor trust for US purposes. Under IRC § 672, a trust is a grantor trust if the settlor (or a related party) retains certain powers, including the power to revoke, the power to control beneficial enjoyment, or the power to borrow without adequate security. Many Hong Kong discretionary trusts, where the settlor serves as a protector with veto power over distributions, inadvertently create grantor trust status. The consequence is that all trust income—whether Hong Kong-sourced or not—is taxable directly to the settlor under IRC § 671, defeating the purpose of asset protection and income deferral.

The solution for US-HK families is to structure the trust as a non-grantor foreign trust under IRC § 679. This requires that no US person (including the settlor) retains a power that would trigger grantor status. The trust must have a Hong Kong-resident trustee that is independent of the settlor, and the settlor must not have the power to remove the trustee without cause or to direct trust investments. The IRD’s new trustee-residence test, effective from the 2023-24 assessment year, requires that the trustee be a Hong Kong resident company or an individual ordinarily resident in Hong Kong, and that the trust’s central management and control be exercised in Hong Kong. A trust that meets this test is treated as a Hong Kong resident trust for profits tax purposes, meaning its income from non-Hong Kong sources is exempt from Hong Kong tax under the territorial source principle (Section 14, Inland Revenue Ordinance, Cap. 112).

US Situs Assets and the Estate Tax Trap

The most common error in cross-border trust planning is transferring US situs assets into a Hong Kong trust without addressing the estate tax exposure. Under IRC § 2104, US situs assets held by a non-resident alien (NRA) decedent are subject to US estate tax at a rate of 18% to 40%, with an exemption of only USD 60,000 (as of 2024). If the settlor dies while retaining a power over the trust (e.g., as a protector), the trust assets are includible in the settlor’s gross estate under IRC § 2036. For a US citizen settlor, the full value of the trust assets—even if they are non-US situs—is subject to estate tax under the worldwide estate tax regime (IRC § 2001).

The practical workaround is to ensure that the Hong Kong trust holds only non-US situs assets. For a Hong Kong-based settlor, this typically means holding Hong Kong listed shares, Hong Kong real estate, and offshore bank accounts in Singapore or Switzerland. US situs assets should be transferred out of the trust before the settlor’s death, or held through a separate non-grantor trust that is irrevocable and has no US beneficiaries. The US-Hong Kong TIEA does not provide for estate tax credits, so any US estate tax paid on trust assets is a direct cost to the estate.

The Hong Kong Territorial Source Rule and Trust Income Taxation

Hong Kong’s territorial source rule is the foundation of the jurisdiction’s appeal as a trust situs. Under Section 14 of the IRO, profits tax is chargeable only on profits arising in or derived from Hong Kong. For a Hong Kong trust, the question is whether the trust’s income—dividends, interest, rental income, capital gains—has a Hong Kong source. The IRD’s Departmental Interpretation and Practice Notes (DIPN) No. 44 (Revised, 2023) clarifies that the source of trust income depends on where the trustee exercises its duties and where the trust’s assets are located. If the trustee is a Hong Kong company and the trust assets are held outside Hong Kong, the income is generally treated as offshore-derived and exempt from profits tax.

This creates a planning opportunity for multi-generational wealth transfer. A Hong Kong trust that holds a portfolio of non-Hong Kong equities and bonds can accumulate income free of Hong Kong tax, and distribute that income to non-Hong Kong resident beneficiaries free of Hong Kong tax as well (since distributions are not taxable in Hong Kong in the hands of beneficiaries). The US tax treatment, however, depends on the beneficiary’s status. A US beneficiary who receives a distribution from a foreign non-grantor trust must report the distribution under the complex throwback rules of IRC § 665-668. The distribution is taxed as ordinary income to the extent of the trust’s undistributed net income (UNI), regardless of the character of the income in the trust’s hands. This can result in a higher effective tax rate than if the income had been earned directly by the beneficiary.

The Throwback Rule Trap for US Beneficiaries

The throwback rule is the single most punitive feature of US taxation of foreign trusts for Hong Kong families with US beneficiaries. Under IRC § 665, any distribution to a US beneficiary from a foreign non-grantor trust that exceeds the trust’s distributable net income (DNI) for the current year is treated as an accumulation distribution. The distribution is then “thrown back” to the earliest year in which the trust had UNI, and the beneficiary is taxed at the marginal rate that would have applied in that year, plus an interest charge under IRC § 668. For a trust that has accumulated income for 10 or 20 years, the interest charge alone can exceed the underlying tax.

The planning response is to ensure that the trust distributes its DNI annually to non-US beneficiaries, or to make a “deemed distribution” election under IRC § 666 to pay the tax at the trust level. For a Hong Kong trust with US beneficiaries, the more efficient structure is often a “domestic trust election” under IRC § 7701(a)(30)(E), which treats the foreign trust as a US trust for tax purposes. This election eliminates the throwback rule but subjects the trust to US tax on its worldwide income. For a trust that holds primarily Hong Kong assets, this may be acceptable if the trust’s income is low or if the settlor is willing to pay US tax at the trust level.

Hong Kong Trusts and the US Estate Tax Return (Form 706)

A US citizen settlor who dies while a Hong Kong trust is in existence must file Form 706 (US Estate Tax Return) if the decedent’s gross estate exceeds the applicable exclusion amount (USD 12.92 million in 2024, scheduled to drop to approximately USD 5 million in 2026). The trust assets are reportable on Schedule G (Transfers During Decedent’s Life) if the settlor retained any interest or power over the trust. The IRS has a three-year statute of limitations for assessing estate tax under IRC § 6501, but if the trust is not disclosed on the return, the statute remains open indefinitely.

For Hong Kong trusts that hold non-US situs assets, the estate tax exposure is limited to the settlor’s retained interests. If the trust is irrevocable and the settlor has no powers, the trust assets are not included in the gross estate. This is the central advantage of a properly structured Hong Kong trust: it removes assets from the US gross estate without triggering gift tax, provided the transfer is a completed gift and the assets are non-US situs.

The US-China Tax Treaty and Hong Kong Trusts: Article 4 Residence Analysis

Hong Kong is not a party to the US-China Double Taxation Agreement (DTA) in its own right. The DTA applies to Hong Kong residents only through the 1998 Exchange of Notes between the US and China, which extended the treaty’s coverage to Hong Kong for certain provisions, including Article 4 (Residence) and Article 13 (Capital Gains). For trust purposes, the critical question is whether a Hong Kong trust can claim treaty benefits as a “resident of Hong Kong” under Article 4.

The DTA defines a resident as a person who is liable to tax in a contracting state by reason of domicile, residence, or place of management. A Hong Kong trust is not itself liable to tax in Hong Kong—the trustee is the taxpayer. However, the IRD’s practice, as set out in DIPN No. 44, is to treat the trust as a taxable entity for treaty purposes if the trustee is a Hong Kong resident and the trust’s central management and control is in Hong Kong. This position is supported by the OECD’s 2010 Report on the Tax Treaty Treatment of Trusts, which provides that a trust may be treated as a resident if it is subject to tax in the state of its establishment.

For US-HK families, the treaty’s Article 13 (Capital Gains) is particularly relevant. It provides that gains from the alienation of shares in a company that derives more than 50% of its value from real property in one contracting state are taxable in that state. If a Hong Kong trust holds shares in a US real property holding company (USRPHC), the gain on sale is taxable in the US under the Foreign Investment in Real Property Tax Act (FIRPTA), regardless of the trust structure. The treaty does not override FIRPTA for US situs real property.

The Exit Tax for US Citizens Relinquishing Citizenship

For a US citizen in Hong Kong considering a trust as part of a broader plan to relinquish citizenship, the exit tax under IRC § 877A must be addressed. The exit tax applies to covered expatriates—those with a net worth exceeding USD 2 million on the date of expatriation, or an average annual net income tax liability exceeding USD 201,000 (2024 threshold, adjusted for inflation). The tax is imposed on a deemed sale of all the expatriate’s worldwide assets, including trust interests.

Under IRC § 877A(g)(1)(A), a trust interest is treated as an asset for exit tax purposes. If the trust is a grantor trust, the settlor is deemed to own the trust assets and must pay tax on the unrealized gain. If the trust is a non-grantor trust, the settlor’s interest is valued at fair market value, and the gain is calculated as the difference between that value and the settlor’s basis. The exit tax cannot be avoided by transferring assets into a trust before expatriation—the transfer itself is a gift for US tax purposes, and the gift tax exemption may be insufficient after the 2025 sunset.

The planning strategy is to structure the trust as a non-grantor trust well before the expatriation date, and to ensure that the trust’s assets are non-US situs to minimize the deemed sale gain. The US-Hong Kong TIEA does not provide for an exit tax credit, so any US exit tax paid is a final cost.

Actionable Takeaways

1. Transfer US situs assets out of any Hong Kong trust before 31 December 2025 to avoid the estate tax trap under IRC § 2036 and to preserve the higher gift tax exemption before the TCJA sunset.

2. Structure the Hong Kong trust as a non-grantor foreign trust under IRC § 679, with an independent Hong Kong-resident trustee and no settlor powers, to avoid current US income tax on trust earnings and to remove assets from the settlor’s gross estate.

3. Ensure the trust’s central management and control is exercised in Hong Kong to qualify for territorial source exemption under Section 14 of the IRO and to meet the IRD’s trustee-residence test under the 2023 amendment.

4. Do not name US beneficiaries in a Hong Kong trust without first modeling the throwback rule under IRC § 665-668; consider a domestic trust election or annual DNI distributions to non-US beneficiaries to avoid the interest charge.

5. For US citizens considering expatriation, establish the non-grantor trust at least two years before the planned expatriation date to ensure the trust interest is not subject to the exit tax under IRC § 877A and to allow time for the IRS statute of limitations to run on any gift tax issues.

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