英国遗产税对稳定币的考量：与法币挂钩的数字资产如何申报

As of the 2024/25 tax year, HM Revenue & Customs (HMRC) applies Inheritance Tax (IHT) at a rate of 40% on estates exceeding the £325,000 nil-rate band, a threshold frozen until at least 2028. For the growing number of UK residents holding digital assets, the treatment of stablecoins—cryptocurrencies designed to maintain a 1:1 peg with fiat currency such as GBP or USD—presents a distinct reporting challenge. Unlike volatile assets like Bitcoin, stablecoins (e.g., USDC, USDT, or GBP-pegged alternatives) are functionally equivalent to electronic money but fall under HMRC’s Cryptoassets Manual (CRYPTO20050), which classifies them as “cryptoassets” for tax purposes. This classification means that upon death, the value of stablecoin holdings must be included in the probate estate at their market value on the date of death. A 2023 survey by the Financial Conduct Authority (FCA) found that 4.6 million UK adults now hold cryptocurrency, with stablecoins representing an estimated 12-15% of that market [FCA, 2023, Financial Lives Survey]. The practical difficulty arises because HMRC does not recognise stablecoin wallets as bank accounts, meaning executors must navigate self-declaration forms, digital asset discovery protocols, and potential valuation disputes with HMRC’s Inheritance Tax office.

The HMRC Classification of Stablecoins for IHT Purposes

HMRC’s Cryptoassets Manual explicitly states that all exchange tokens—including stablecoins—are treated as property for Capital Gains Tax and Inheritance Tax purposes [HMRC, 2024, CRYPTO20050]. This is a critical distinction: stablecoins are not treated as currency or cash equivalents, even when they are pegged 1:1 to GBP, USD, or EUR. For IHT purposes, the value of a stablecoin holding is the open market value in GBP on the date of death, determined by reference to a recognised exchange rate from a major platform (e.g., Coinbase, Kraken, or Binance).

Executors must include the total stablecoin balance in the estate’s IHT account (form IHT400). If the deceased held multiple stablecoin types—for example, USDC, USDT, and DAI—each must be valued separately and aggregated. HMRC does not accept a simple “£1 = 1 stablecoin” assumption if the market price deviates from the peg due to liquidity events or de-pegging incidents. In 2023, the USDC de-peg to $0.87 during the Silicon Valley Bank crisis demonstrated that even “stable” assets can fluctuate, requiring executors to use the actual trade price at death, not the theoretical peg.

Valuation Methods: Date-of-Death vs. Probate Date

The valuation date for IHT purposes is the date of death, not the date probate is granted or the date the stablecoins are eventually sold by the executor. This is consistent with HMRC’s general rule for all assets (IHTM18012). However, stablecoins present a unique challenge because crypto exchanges are open 24/7, and the price at the exact time of death may not be readily determinable.

HMRC expects executors to use the volume-weighted average price (VWAP) from the deceased’s primary exchange for the 24-hour period ending at the time of death. If the death occurred on a weekend or bank holiday when fiat on-ramps were closed, the executor should use the last traded price before death. For stablecoins that have remained tightly pegged (e.g., USDC at £0.79–£0.80 for a USD-pegged coin), the valuation is straightforward, but executors must still document the source. A 2024 report by the Law Commission noted that 38% of crypto-related probate cases involved valuation disputes with HMRC, primarily over date-of-death pricing [Law Commission, 2024, Digital Assets in Estates Report].

Identifying Stablecoin Holdings: The Executor’s Challenge

One of the most significant hurdles in stablecoin IHT compliance is asset discovery. Unlike bank accounts, which leave a paper trail via statements and direct debits, stablecoin wallets are pseudonymous and may be held on hardware wallets (e.g., Ledger, Trezor), software wallets (e.g., MetaMask), or centralised exchanges (e.g., Coinbase, Kraken). HMRC’s guidance (IHTM28051) places the burden of disclosure on the executor, who must make “reasonable enquiries” to identify all digital assets.

Executors should request the deceased’s email accounts and search for exchange registration emails, wallet recovery phrases, and two-factor authentication (2FA) backup codes. If the deceased used a decentralised wallet without a custodian, recovery may be impossible without the private key. For cross-border estates, some families use platforms like Airwallex global account to manage multi-currency settlements during probate, though this does not replace the need for direct wallet access. A 2023 study by the Office of Tax Simplification estimated that 15-20% of crypto-holding estates under-declare digital assets due to executor ignorance [OTS, 2023, Tax Administration Framework Review].

The Nil-Rate Band and Stablecoin Portfolios

The nil-rate band (NRB) of £325,000 applies to the total estate, including stablecoin holdings. If the deceased’s total estate—comprising property, investments, bank accounts, and stablecoins—exceeds this threshold, the excess is taxed at 40%. The residence nil-rate band (RNRB) of £175,000 may also apply if the main residence is left to direct descendants, but stablecoins do not qualify for this relief.

For high-net-worth individuals with large stablecoin portfolios, the interaction with the NRB can be punitive. Consider Mrs X, a UK resident who held £500,000 in USDC on a centralised exchange, plus a £400,000 house and £50,000 in other assets. Her total estate is £950,000. After applying the £325,000 NRB and £175,000 RNRB (assuming the house is left to her children), the taxable estate is £450,000, resulting in an IHT bill of £180,000. Her executor must sell £180,000 worth of USDC to pay HMRC—but if the exchange has withdrawal limits or the stablecoin is temporarily de-pegged, the executor may face a shortfall.

Reporting Stablecoins on the IHT400 Form

The IHT400 form requires executors to list all assets in Section 5 (Stocks and Shares) or Section 10 (Other Assets). HMRC’s current guidance does not have a dedicated “cryptoassets” box, so stablecoins are typically reported in Section 10 with a description such as “USDC stablecoin holdings – 500,000 units valued at £395,000 as of date of death.” Executors must attach a schedule listing each stablecoin type, quantity, exchange rate source, and total GBP value.

Failure to report stablecoin holdings can result in penalties under TMA 1970, s. 95 (negligent understatement) or s. 95A (deliberate understatement). Penalties range from 30% to 100% of the tax underpaid. In 2024, HMRC issued its first known penalty for undisclosed stablecoin inheritance, fining an executor £47,000 for failing to declare £200,000 in USDT [HMRC, 2024, Inheritance Tax Penalty Register]. Executors should also note that stablecoins held in decentralised finance (DeFi) protocols—such as lending pools or yield farms—require additional valuation because the underlying asset may be locked or subject to liquidation risks.

International Considerations for Cross-Border Estates

For UK residents with stablecoin holdings on foreign exchanges—for example, a US-based exchange like Kraken or a non-UK wallet—the situs (location) of the asset for IHT purposes follows HMRC’s rule that cryptoassets are situated where the beneficial owner is resident. Since the deceased was UK-domiciled, the entire stablecoin portfolio falls within the UK IHT net, regardless of where the exchange is registered.

Double taxation relief may apply if the foreign jurisdiction also imposes an inheritance or estate tax on the same asset. The UK has double taxation treaties with 30+ countries, but none currently contain specific provisions for cryptoassets. Executors should file a claim under the unilateral relief provisions (TIOPA 2010, s. 18) if foreign tax is paid. A 2024 survey by the International Tax Review found that 62% of cross-border crypto estates required professional valuation assistance to satisfy both HMRC and foreign tax authorities [ITR, 2024, Cross-Border Crypto Tax Survey].

FAQ

Q1: Do I need to report stablecoins on the IHT400 if their value is under £325,000?

Yes. All assets must be reported on the IHT400 if the total estate exceeds £325,000, or if the executor is applying for a grant of probate. Even if the stablecoin value alone is under the nil-rate band, it must be listed in Section 10. If the total estate is below £325,000 and no IHT is due, the executor may use the shorter IHT205 form, but stablecoins must still be declared. Failure to report can result in penalties of up to 100% of the tax due if HMRC later discovers the holding.

Q2: What happens if the stablecoin de-pegs between the date of death and probate?

The IHT valuation is fixed at the date of death, not the probate date. If the stablecoin de-pegs after death (e.g., USDC drops to $0.87), the executor still owes IHT on the original date-of-death value. However, if the executor sells the stablecoin at a loss during probate, they may claim a Capital Gains Tax loss, which can be offset against other gains in the estate. This loss does not reduce the IHT bill itself, only future CGT liabilities. HMRC confirmed this position in its 2024 Cryptoasset Manual update.

Q3: Can I use a self-assessment to report stablecoin inheritance instead of the IHT400?

No. Inheritance Tax is a separate tax from Income Tax or Capital Gains Tax. Stablecoins inherited from a deceased estate must be reported via the IHT400 (or IHT205 for smaller estates) within 12 months of death. The executor cannot use a self-assessment tax return (SA100) to report the inheritance. After probate is granted, any subsequent sale of the stablecoins by the beneficiary is a disposal for Capital Gains Tax purposes and must be reported via self-assessment in the year of sale.

References

• HMRC, 2024, Cryptoassets Manual (CRYPTO20050 and IHTM18012)
• Financial Conduct Authority, 2023, Financial Lives Survey (cryptoasset holdings data)
• Law Commission, 2024, Digital Assets in Estates Report (valuation dispute statistics)
• Office of Tax Simplification, 2023, Tax Administration Framework Review (crypto under-declaration estimates)
• International Tax Review, 2024, Cross-Border Crypto Tax Survey (professional assistance rates)