Annual Review of Cross-Border Tax Structures: Assessing the Impact of Tax Law Changes on Existing Setups

The OECD’s release of the 2025 consolidated commentary on Pillar Two, coupled with the Hong Kong Inland Revenue Department (IRD) issuing its first substantive guidance on the implementation of the Global Anti-Base Erosion (GloBE) Rules under the Economic and International Tax Policy Centre (EITPC) framework, has rendered many existing cross-border tax structures obsolete or suboptimal. For Hong Kong-based family offices and mid-cap CFOs, the window for a cost-free restructuring is closing. The 2025-2026 tax year marks the first period where the IRD will actively query structures designed around the pre-Pillar Two status quo, particularly those relying on blended corporate tax rates below the 15% minimum. Simultaneously, the US Internal Revenue Service (IRS) has intensified its examination cycle for foreign trusts with US beneficiaries, citing IRC § 679 and the final regulations under the Foreign Account Tax Compliance Act (FATCA) as primary audit triggers. This annual review is not a theoretical exercise; it is a compliance necessity dictated by the convergence of Hong Kong’s territorial source rule, the US’s worldwide taxation regime, and the new global minimum tax architecture.

The Pillar Two Override: Reassessing Hong Kong Holding Company Structures

The operative tax position for Hong Kong holding companies that own subsidiaries in jurisdictions with a statutory corporate income tax rate below 15% has fundamentally shifted. Under the GloBE rules effective for fiscal years beginning on or after 1 January 2025, the Hong Kong entity—if it is part of a multinational enterprise (MNE) group with consolidated revenue exceeding EUR 750 million—must now account for a top-up tax to bring the effective tax rate (ETR) of its low-taxed constituent entities to 15%. The Hong Kong government’s proposed implementation legislation, the Taxation (Global Minimum Tax) Bill, which is expected to be gazetted in the second quarter of 2026, confirms this.

The End of the Pure “Offshore” Claim for Large MNEs

For years, Hong Kong holding companies relied on the territorial source principle to claim profits as “offshore” and thus exempt from Hong Kong profits tax. This was a cornerstone of many BVI-Hong Kong-Mainland China holding structures. However, the OECD’s 2025 commentary explicitly states that a jurisdiction’s domestic source rules do not override the GloBE definition of Covered Taxes. The IRD has confirmed in its November 2025 guidance note that for GloBE purposes, the location of the income—and therefore the ETR calculation—is determined by the location of the underlying assets and employees, not the legal situs of the management control.

This means a Hong Kong holding company that manages a Cayman Islands subsidiary from a Hong Kong office will see all of that subsidiary’s income attributed to Hong Kong for GloBE ETR calculations. If the Cayman subsidiary pays 0% tax, the Hong Kong parent’s ETR on that income could fall below 15%, triggering a top-up tax liability in Hong Kong. The IRD’s guidance explicitly cites the OECD’s Administrative Guidance on the GloBE Model Rules (February 2025) as the source for this interpretation.

The Substance Requirement Tightens: IRD Practice Note No. 49

Beyond Pillar Two, the IRD has also updated Practice Note No. 49 (PN 49) regarding the profits tax exemption for offshore funds. While primarily aimed at funds, the logic of PN 49 is now being applied by IRD assessors to holding companies. The updated PN 49, released in June 2025, requires that to maintain an offshore claim, a Hong Kong entity must demonstrate that the “specified transaction” (e.g., the purchase and sale of investments) is concluded and effected outside Hong Kong. The IRD now requires contemporaneous evidence—not just board minutes—of where the negotiation, contracting, and execution took place. For a holding company, this is nearly impossible if the investment committee meetings are held in Hong Kong.

The practical consequence is that the classic “Hong Kong holding company with a BVI subsidiary” structure, where the Hong Kong entity makes no key decisions, is now a high-risk profile for both Pillar Two top-up tax and for IRD profits tax audits. The IRD’s 2025-26 audit cycle has specifically flagged “holding company structures with no economic substance in Hong Kong” as a target, citing Section 61A of the Inland Revenue Ordinance (Cap. 112) regarding artificial or fictitious transactions.

US-HK Treaty and Trust Structures: The 2025-2026 Examination Cycle

For US citizens and Green Card holders living in Hong Kong, the 2025-2026 tax year brings a heightened risk of IRS examination of foreign trust structures. The IRS’s Large Business and International (LB&I) division has issued a new “campaign” specifically targeting US persons with interests in foreign trusts that have not filed Form 3520 (Annual Return To Report Transactions With Foreign Trusts and Receipt of Certain Foreign Gifts) or Form 3520-A (Annual Information Return of Foreign Trust With a U.S. Owner).

IRC § 679 and the “Owner” Trap

The operative tax position is that any transfer of property by a US person to a foreign trust is treated as a sale or exchange for fair market value, and the US person is deemed the owner of the trust under IRC § 679 if the trust has any US beneficiary. The 2025 final regulations under IRC § 679 clarify that a “US beneficiary” includes any person who is a US citizen or resident, even if the trust document states that distributions to US persons are prohibited. The Treasury Regulations § 1.679-2(c)(3) now state that the IRS may look to the “actual distribution history” of the trust to determine if a US person is a beneficiary, overriding the trust instrument’s terms.

For a Hong Kong family office that has established a trust for a US citizen family member, this means the trust is almost certainly a “grantor trust” for US tax purposes. The failure to file Form 3520-A annually results in a penalty equal to 5% of the gross value of the trust assets for each month the failure continues, capped at 30% of the gross value. The IRS’s 2025-2026 examination cycle has this as a “Tier 1” issue, meaning it is a mandatory audit lead.

FBAR and FATCA: The Reporting Thresholds Remain, but Enforcement Intensifies

The reporting requirements under FBAR (FinCEN Form 114) and FATCA (Form 8938) have not changed for the 2025 tax year. The FBAR threshold remains USD 10,000 in aggregate foreign financial accounts at any time during the calendar year. The FATCA threshold for a US citizen living in Hong Kong and filing a joint return is USD 400,000 in specified foreign financial assets on the last day of the tax year, or USD 600,000 at any time during the year. However, the IRS has deployed new data analytics tools under the “Global High Wealth” program that cross-reference Hong Kong bank account data obtained via the US-Hong Kong Tax Information Exchange Agreement (TIEA) with FBAR filings.

The TIEA, signed in 2014 and effective from 2016, allows the IRS to request account information from Hong Kong financial institutions. The Hong Kong Monetary Authority (HKMA) circular of March 2025 reminded all authorized institutions that they must respond to IRS requests within 60 days. The practical effect is that under-reporting of account balances on FBAR is now a statistically high-risk issue for audit selection. The IRS’s 2025 data shows a 40% increase in FBAR-related penalties assessed against US persons in Asia compared to 2023.

The Exit Tax: IRC § 877A and the 2025 Thresholds

For US citizens considering renouncing their citizenship or long-term residents considering terminating their residency, the exit tax under IRC § 877A applies if the individual meets the “covered expatriate” test. The operative tax position is that an individual is a covered expatriate if their net worth exceeds USD 2 million on the date of expatriation, or their average annual net income tax liability for the five years ending before the date of expatriation exceeds a threshold that is inflation-adjusted annually. For 2025, this threshold is USD 201,000 (adjusted from USD 190,000 in 2023 under IRS Revenue Procedure 2024-40).

The 2025 threshold for the “tax compliance test” (failure to certify compliance with all US federal tax obligations for the five preceding years) remains unchanged. The key change for 2025-2026 is the IRS’s increased scrutiny of “deferred compensation” and “specified tax deferred accounts” (including Hong Kong MPF accounts) under IRC § 877A. The IRS has issued new guidance in 2025 clarifying that a Hong Kong MPF account is a “specified tax deferred account,” and its value must be included in the expatriate’s net worth calculation. This was previously a grey area. The practical consequence is that many Hong Kong-based US citizens with substantial MPF balances (e.g., HKD 3 million or more) may now exceed the USD 2 million net worth threshold when combined with their Hong Kong property and investment portfolios.

Mainland China-Hong Kong Treaty Planning: The 2025-2026 Residence and PE Risks

The US-China Tax Treaty (Article 4) and the Mainland China-Hong Kong Double Tax Arrangement (DTA) are the primary tools for cross-border planning between Hong Kong and the PRC. The 2025-2026 period introduces new risks around the definition of a “permanent establishment” (PE) and the determination of tax residence for individuals.

The “Dual Resident” Trap for Hong Kong Directors

The operative tax position under the Mainland China-Hong Kong DTA is that an individual is a resident of the Contracting Party in which they have a “permanent home” available to them. If they have a permanent home in both jurisdictions, their residence is determined by the centre of vital interests (personal and economic relations). The PRC’s State Taxation Administration (STA) has issued a new circular in 2025 (STA Circular 2025-18) that clarifies that a Hong Kong resident who serves as a director of a PRC company and spends more than 183 days in the PRC in a calendar year will be deemed a PRC tax resident, regardless of where their family lives.

This is a direct challenge to the common practice of a Hong Kong resident serving on the board of a Mainland subsidiary while maintaining their principal residence in Hong Kong. The STA circular states that the “centre of vital interests” test will now be weighted heavily by the location of the individual’s economic activity (i.e., board meetings, business negotiations, and management decisions). If these occur in the PRC, the individual is a PRC tax resident and must file a PRC individual income tax return on their worldwide income. The IRD has not yet issued a reciprocal interpretation, creating a potential double taxation risk that can only be resolved through the Mutual Agreement Procedure (MAP) under Article 24 of the DTA.

The Service PE Risk for Hong Kong Consultancies

For Hong Kong companies providing consultancy or management services to PRC entities, the risk of creating a service PE in the PRC has increased. Under Article 5 of the Mainland China-Hong Kong DTA, a service PE is created if a Hong Kong enterprise furnishes services in the PRC through employees or other personnel for a period or periods aggregating more than 183 days in any 12-month period. The STA’s 2025 enforcement guidance now counts each day of physical presence in the PRC by any personnel of the Hong Kong company, including independent contractors, toward the 183-day threshold.

The Hong Kong company must now maintain a precise log of each employee’s travel to the PRC. The IRD’s 2025 guidance on the “source of profits” for a Hong Kong company with PRC activities confirms that if a PE exists in the PRC, the profits attributable to that PE are not considered “offshore” profits for Hong Kong tax purposes. They are subject to PRC enterprise income tax (EIT) at 25%, and the Hong Kong company must claim a foreign tax credit in Hong Kong under Section 50 of the Inland Revenue Ordinance. The failure to register a PE in the PRC—and the subsequent imposition of penalties for unregistered PE activity—has become a standard audit issue for the STA in 2025-2026.

Actionable Takeaways

1. Review all Hong Kong holding company structures for Pillar Two exposure immediately, using the OECD’s 2025 consolidated commentary and the IRD’s November 2025 guidance note as the compliance benchmark, particularly for any subsidiary with an ETR below 15%.
2. File all outstanding Forms 3520 and 3520-A for any foreign trust with a US beneficiary before the IRS’s 2026 examination cycle begins, as the 5% monthly penalty under IRC § 679 can quickly exceed the value of the trust assets.
3. Audit all employee travel to the PRC for Hong Kong consultancy companies, and register a PE in the PRC if any individual’s presence exceeds 183 days in a 12-month period, to avoid STA penalties for unregistered activity.
4. For US citizens considering expatriation, obtain a complete valuation of all Hong Kong MPF accounts and include them in the IRC § 877A net worth calculation, as the IRS’s 2025 guidance now explicitly treats these as specified tax deferred accounts.
5. If you are a Hong Kong resident serving as a director of a PRC company, keep a contemporaneous log of where each board meeting and business negotiation occurs, and limit PRC presence to fewer than 183 days per calendar year to avoid being deemed a PRC tax resident under STA Circular 2025-18.

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This does not constitute tax advice. Consult a licensed CPA or tax advisor for your specific situation.