Tax-Loss Harvesting for US Stock Portfolios: Offsetting Capital Gains While Living in Hong Kong

For a US citizen or green card holder residing in Hong Kong, the obligation to file US federal income tax returns remains regardless of where the income is sourced. This creates a unique tax planning environment where the US tax system’s rules on capital gains and losses intersect with a zero-capital-gains-tax jurisdiction. The US stock market’s performance in 2024 and early 2025, marked by significant sector rotation and increased volatility in growth and technology stocks, has presented a window for many Hong Kong-based investors to realise losses. With the Internal Revenue Service (IRS) intensifying its focus on high-net-worth individuals and cross-border compliance through initiatives like the Employee Retention Credit moratorium and increased funding for examinations, the discipline of tax-loss harvesting (TLH) is no longer a passive strategy. For the US person living in Hong Kong, TLH offers a direct mechanism to offset realised capital gains from profitable positions, thereby reducing US federal income tax liability, without triggering a Hong Kong tax event due to the territory’s source-based taxation principle under the Inland Revenue Ordinance (Cap. 112). The window for 2025 tax-year planning is now open, and the rules governing wash sales, capital loss carryforwards, and the interaction with foreign tax credits require careful attention.

The Mechanics of Tax-Loss Harvesting Under IRC § 1211 and § 1212

The Core Statutory Framework

Tax-loss harvesting for a US person living in Hong Kong operates under the same Internal Revenue Code rules as for a US resident, but without the complication of state-level capital gains taxes. The primary authority is IRC § 1211, which limits the deduction of capital losses. For a taxpayer filing as single or married filing jointly, capital losses are allowed to the extent of capital gains, plus an additional USD 3,000 per tax year (or USD 1,500 for married filing separately). This deduction is applied against ordinary income, such as salary or interest, which can be particularly valuable for a Hong Kong-based US citizen who may have little US-source income but significant Hong Kong-sourced salary that is excluded from US taxation under IRC § 911 (Foreign Earned Income Exclusion, FEIE). The FEIE for 2024 is capped at USD 126,500 per tax year, and for 2025 it is USD 130,000. Any capital losses harvested from a US brokerage account are netted against capital gains first, and any net loss can be used to offset up to USD 3,000 of other income, including income not excluded under FEIE.

The Wash Sale Rule: IRC § 1091

The most critical trap for any TLH strategy is the wash sale rule under IRC § 1091. This rule disallows the deduction of a loss from the sale of securities if the taxpayer acquires substantially identical stock or securities within a 61-day window—30 days before and 30 days after the sale. For a Hong Kong-based investor, this rule applies to transactions in any US brokerage account, including those held by a non-US entity like a BVI or Cayman Islands corporation if the US person is the beneficial owner. The IRS has consistently taken the position that the wash sale rule applies to accounts under common control (Rev. Rul. 2008-5). Practitioners should note that the rule applies to options, contracts, and certain ETFs that track the same index. A common error for Hong Kong residents is triggering a wash sale by repurchasing the same stock in a retirement account (e.g., an IRA) within the 61-day period, which is also prohibited under IRS guidance (Revenue Ruling 2008-5).

Capital Loss Carryforwards Under IRC § 1212

If the net capital loss for a tax year exceeds the USD 3,000 limitation, the excess is carried forward indefinitely under IRC § 1212(b). This carryforward retains its character as short-term or long-term, which is relevant for offsetting future gains. For a Hong Kong-based US person planning to return to the US or to generate substantial US-source capital gains in future years, building a capital loss carryforward is a strategic asset. The carryforward is reported on Schedule D (Form 1040) and carried forward on Form 1040, line 7, in subsequent years. It does not expire, unlike some other tax attributes. This is particularly advantageous for investors who hold concentrated positions in high-growth stocks that have declined, as the loss can be harvested now and used to offset gains from a future IPO, stock sale, or real estate disposition.

Practical Implementation for the Hong Kong Resident

Identifying Harvestable Losses in a Global Portfolio

A US person living in Hong Kong often maintains a multi-jurisdictional portfolio, including US brokerage accounts (e.g., Schwab, Fidelity, Interactive Brokers), Hong Kong-listed stocks, and perhaps a Singapore or UK brokerage. For TLH purposes, only losses on assets that are subject to US capital gains tax are relevant. Hong Kong-listed stocks, for example, are generally not subject to US capital gains tax unless the US person holds them through a US brokerage account and sells them, triggering a US taxable event. The Hong Kong Inland Revenue Ordinance (Cap. 112) does not impose a capital gains tax, so there is no Hong Kong tax consequence from realising a loss on a Hong Kong stock. However, the US person must still report the sale on Form 8938 (if the aggregate value of specified foreign financial assets exceeds USD 50,000 for a taxpayer living abroad) and on FinCEN Form 114 (FBAR) if the account balance exceeds USD 10,000 at any time during the calendar year. The loss is realised in US dollars, and the exchange rate at the date of sale is used for conversion (using the annual average rate from the IRS or the spot rate, per Rev. Rul. 2008-5).

Timing and Execution: The December Window

The optimal time for TLH is typically in the final quarter of the tax year, from October to December, when the investor has a clearer picture of their realised gains for the year. For a Hong Kong resident, the timing is further influenced by the US tax filing deadline (April 15, 2025 for the 2024 tax year, with an automatic six-month extension to October 15, 2025). The wash sale rule requires that the sale and repurchase not occur within 30 days of each other. A common strategy is to sell a losing position in late December and wait until late January to repurchase, avoiding the wash sale rule while staying invested. For a Hong Kong resident, this means the cash from the sale may sit in a money market fund or a short-term Treasury bill during the waiting period. The interest earned on that cash is US-source interest, which is generally not subject to US withholding tax if paid to a non-US person, but for a US citizen, it is fully taxable on the US return. This interest income is also not eligible for the FEIE, so it is taxed at ordinary income rates.

Reporting Requirements for the Hong Kong Resident

The TLH transactions must be reported on the US tax return. For a Hong Kong resident, the key forms are:

• Schedule D (Form 1040): Reports all capital gains and losses.
• Form 8949: Provides details of each sale, including the date acquired, date sold, proceeds, cost basis, and the amount of gain or loss.
• Form 8938: If the total value of specified foreign financial assets exceeds the threshold (USD 200,000 for a taxpayer living abroad at the end of the tax year, or USD 300,000 at any time during the year), the brokerage account must be reported.
• FinCEN Form 114 (FBAR): If the aggregate value of foreign financial accounts exceeds USD 10,000 at any time during the calendar year.

A common compliance error for Hong Kong residents is failing to report the cost basis correctly for shares acquired through a corporate action, such as a stock split or merger, or for shares acquired through an employee stock purchase plan (ESPP). The IRS requires the use of specific identification method or average cost method for mutual funds, but for individual stocks, the taxpayer must use the specific identification method to avoid a wash sale.

Strategic Considerations for the Hong Kong-Based US Person

The Interaction with the Foreign Tax Credit

For a US person living in Hong Kong, the foreign tax credit (FTC) under IRC § 901 is a critical tool for avoiding double taxation on foreign-source income. However, capital gains are generally sourced to the country of residence of the seller (the US for a US citizen). Therefore, capital gains from US stocks are US-source income, and no foreign tax credit is available for any foreign tax paid on that gain. Conversely, capital gains from Hong Kong stocks are foreign-source income, and any Hong Kong tax paid (which is zero for capital gains) is irrelevant. The FTC cannot be used to offset US tax on US-source capital gains. This means that TLH is a pure US tax benefit, with no Hong Kong tax offset. For a Hong Kong resident who pays significant Hong Kong salaries tax (up to 15% under the standard rate), the FTC can offset US tax on foreign-source salary, but not on US-source capital gains. Therefore, TLH is one of the few direct ways to reduce US tax liability on US-source investment income.

Planning for the Exit: The US Exit Tax (IRC § 877A)

A US citizen or green card holder who has lived in Hong Kong for many years and is considering relinquishing their US citizenship or long-term resident status must be aware of the exit tax under IRC § 877A. The exit tax applies to individuals with a net worth exceeding USD 2 million, or an average annual net income tax liability exceeding a specified threshold (USD 201,000 for 2024, adjusted for inflation). For such individuals, a capital loss carryforward is generally lost upon expatriation. The IRS treats the taxpayer as having sold all their property at fair market value the day before expatriation, and any built-in gains are taxed. A capital loss carryforward cannot offset this deemed gain. Therefore, TLH should be used strategically before expatriation to realise losses that can offset gains from the deemed sale. This is a high-stakes planning area that requires coordination with a qualified tax advisor.

The Risk of IRS Examination and the Statute of Limitations

The IRS has a three-year statute of limitations for assessing additional tax from the date the return is filed (IRC § 6501(a)). However, if the taxpayer omits more than 25% of gross income, the statute extends to six years (IRC § 6501(e)). For a Hong Kong resident with multiple brokerage accounts and complex reporting (FBAR, FATCA), the risk of an omission is real. A TLH strategy that involves frequent trading or wash sales can increase the complexity of the return and the risk of an error. The IRS has also increased its focus on high-income taxpayers through the Large Business & International division. A capital loss deduction of USD 3,000 is a small amount relative to the overall tax liability, but if the TLH strategy involves a large loss carryforward (e.g., USD 100,000), the IRS may scrutinise the cost basis and the wash sale calculations. Maintaining detailed records of all trades, including the specific identification method for shares, is essential.

Actionable Takeaways for the Hong Kong-Based US Investor

1. Review your US brokerage portfolio for unrealised losses before December 31, 2025, and execute sales that are not subject to the wash sale rule (IRC § 1091) to offset any realised gains for the 2025 tax year.
2. Use the capital loss carryforward (IRC § 1212) as a strategic asset if you anticipate future US-source capital gains from a stock sale, real estate disposition, or business exit, and track the carryforward on Schedule D.
3. Ensure all brokerage accounts, including those held in Hong Kong or through a foreign entity, are reported on Form 8938 and FinCEN Form 114 (FBAR) to avoid penalties for non-compliance, which can be substantial (USD 10,000 per violation for non-willful, and up to 50% of the account balance for willful).
4. Do not repurchase a substantially identical stock or ETF within 30 days of a loss sale, even in a retirement account (IRA), as the wash sale rule applies across accounts under common control (Rev. Rul. 2008-5).
5. Plan TLH in conjunction with any potential expatriation, as a capital loss carryforward is generally forfeited upon relinquishing US citizenship or long-term residency under IRC § 877A.

Disclaimer: This article is for informational purposes only and does not constitute tax advice. US tax laws are complex and subject to change. Consult a licensed CPA or tax advisor for your specific situation. / 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。