UK IHT Valuation of Forked Coins: How to Include New Assets from Blockchain Forks in the Estate

Since the landmark Bitcoin Cash fork in August 2017, over 100 significant blockchain forks have created billions of pounds in new digital assets, yet HM Revenue & Customs (HMRC) has issued no specific statutory guidance on their inheritance tax (IHT) treatment. A 2023 report from the Law Commission of England and Wales estimated that approximately 4.2 million UK adults now hold some form of cryptoasset, with forked coins—assets created when a blockchain splits—representing an increasingly common but legally ambiguous component of estates. The precise IHT valuation of these coins, which often lack an active exchange price or exist only on a minority chain, presents a distinct challenge for executors and beneficiaries. Without clear HMRC direction, practitioners must rely on general principles from the Inheritance Tax Act 1984, case law on asset valuation at the date of death, and emerging industry standards for digital asset appraisal. This article provides a structured methodology for identifying, valuing, and reporting forked coins within a UK probate context, drawing on the HMRC Cryptoassets Manual (2024 update) and the STEP (Society of Trust and Estate Practitioners) Digital Assets Global Guidance (2022).

Understanding Blockchain Forks and the Creation of New Assets

A blockchain fork occurs when a protocol change splits the network into two separate chains, each with its own transaction history and native token. Hard forks create a new asset that is distinct from the original, while soft forks typically do not. For IHT purposes, the critical distinction is whether the deceased held the private keys to the original blockchain at the time of the fork. If they did, they acquired a corresponding balance of the new forked coin automatically, even if they never actively claimed, sold, or even knew about it.

The most prominent examples include Bitcoin Cash (BCH) forking from Bitcoin (BTC) in August 2017, Bitcoin SV (BSV) forking from BCH in November 2018, and Ethereum Classic (ETC) forking from Ethereum (ETH) in July 2016. Each of these events created a new class of property that, under the broad definition in section 272 of the Inheritance Tax Act 1984, forms part of the deceased’s estate. The key legal principle is that the asset exists from the moment of the fork, not from the moment the holder chooses to access it. This means executors must actively search for forked coins, even if the deceased’s records show only the original blockchain holdings.

HMRC’s position, as outlined in the Cryptoassets Manual (CRYPTO20000, 2024 update), treats each forked coin as a separate cryptoasset for Capital Gains Tax purposes, and by extension, for IHT. There is no de minimis exemption for small-value forks. An executor who fails to identify and value a forked coin with a market value exceeding the estate’s nil-rate band threshold risks an incorrect IHT return and potential penalties under Schedule 24 of the Finance Act 2007.

Identifying Forked Coins in the Estate: Practical Steps for Executors

The first challenge is discovery. Unlike a bank account or a share certificate, a forked coin has no central record. The only way to prove ownership is through control of the private key that signed the transaction on the original blockchain before the fork. Executors must therefore conduct a thorough digital asset inventory.

Step one: review the deceased’s seed phrases and private keys. If the deceased used a hardware wallet (e.g., Ledger, Trezor) or a software wallet (e.g., Electrum, MetaMask), the seed phrase—a 12- or 24-word recovery phrase—grants access to all associated addresses. Many modern wallets automatically show balances for major forks, but some do not. Executors should use a tool like the “Coinomi” or “Atomic Wallet” multi-chain interface to scan the seed phrase across different blockchains. This process is non-destructive and does not require moving any funds.

Step two: examine exchange and custodial account records. If the deceased held crypto on a centralised exchange (e.g., Coinbase, Kraken, Binance), the exchange’s policy on forks is crucial. Some exchanges credited users with forked coins automatically; others did not. Executors should request a complete transaction history from each exchange, including any fork-related airdrops or credit events. The exchange’s terms of service from the fork date will determine whether the forked coin was legally the user’s property or remained with the exchange.

Step three: check blockchain explorers. For public blockchains, an executor can enter a known public address from the deceased’s wallet into a blockchain explorer (e.g., Blockchain.com for BTC, Etherscan for ETH) and view the balance history. This will show whether the address held coins at the block height of a known fork. If it did, the forked chain’s explorer (e.g., BCH explorer for Bitcoin Cash) will show a corresponding balance. This is a free, verifiable, and court-admissible method of evidence.

For cross-border estates where the deceased held assets through a corporate structure or trust, some families use channels like Airwallex global account to manage multi-currency settlement of inheritance liabilities, though this does not replace the need for a proper digital asset inventory.

Valuation Methodology for Forked Coins at Date of Death

Valuing a forked coin at the date of death is the most technically demanding step. HMRC requires the “price which the property might reasonably be expected to fetch if sold in the open market” (section 160, Inheritance Tax Act 1984). For a forked coin, this is not necessarily the spot price on a major exchange, as liquidity may be thin or non-existent.

Principle one: use the most active, regulated exchange price. For major forks like Bitcoin Cash or Ethereum Classic, the price on a UK-regulated exchange (e.g., Coinbase UK, Kraken UK) as of the date of death is the most defensible starting point. The executor should take a snapshot of the order book depth at the time of death (GMT). If the coin was traded on multiple exchanges, the weighted average price across the top three by volume is standard practice, consistent with HMRC’s approach to valuing listed shares.

Principle two: for illiquid or dead forks, apply a discount. Many forks, such as Bitcoin Gold (BTG) or Bitcoin Diamond (BCD), have extremely low trading volumes. If the executor can demonstrate that selling a large block would materially move the price, a “blockage discount” may be appropriate. This is analogous to the discount applied to large shareholdings in a private company. The discount should be supported by a written valuation report from a qualified digital asset appraiser, referencing the spread and volume data from CoinMarketCap or CoinGecko at the valuation date.

Principle three: zero value is acceptable only with evidence. If a forked coin has no active market, no exchange listing, and no development activity, the executor may assign a zero value. However, HMRC may challenge this if the coin later gains value. The executor should retain a screenshot of the CoinMarketCap page showing zero volume and a market cap of zero as of the valuation date. The burden of proof lies with the executor.

Reporting Forked Coins on the IHT Return (Form IHT400)

The IHT400 requires the executor to list all assets of the estate, including “cryptoassets” in the “other assets” section. Forked coins should be listed separately from the original blockchain coins, as they are distinct legal assets with potentially different values and tax bases.

Line item treatment. Each forked coin should be listed on a separate row in the IHT400 supplementary pages (Schedule IHT404 for other assets). The description should include the full name of the coin, the ticker symbol, the blockchain it belongs to, and the number of units held. The value should be the sterling equivalent as calculated using the methodology above, converted at the Bank of England’s daily exchange rate for the date of death.

The nil-rate band interaction. The total value of all cryptoassets, including forked coins, is aggregated with other estate assets. If the total exceeds the nil-rate band (£325,000 for 2024/25, frozen until 2028 per the Autumn Statement 2022), IHT is payable at 40% on the excess. However, if the deceased left at least 10% of their net estate to charity, the rate reduces to 36%. Forked coins that are donated to a qualifying charity within two years of death can also qualify for this relief, provided the charity is willing and able to accept the specific coin.

Risk of under-declaration. HMRC has invested in blockchain analytics tools (e.g., Chainalysis, CipherTrace) to detect undeclared cryptoasset holdings. An executor who omits a forked coin that later appears on a public blockchain explorer risks an HMRC enquiry, with penalties of up to 100% of the tax due for deliberate non-disclosure (Schedule 24, Finance Act 2007).

Case Study: The Estate of Mr Y, a Bitcoin Holder from 2013

Mr Y died in March 2024, leaving an estate comprising a house in Surrey (£850,000), a portfolio of listed shares (£120,000), and a hardware wallet containing 10 Bitcoin (BTC). At the date of death, BTC traded at £45,000 per coin, giving a gross value of £450,000 for the BTC holding alone. However, Mr Y had held his BTC since 2013, meaning he was entitled to forked coins from the Bitcoin Cash (2017), Bitcoin Gold (2017), and Bitcoin SV (2018) forks.

Identification. The executor used the seed phrase from Mr Y’s Ledger wallet to scan for fork balances. The wallet software showed 10 BCH, 10 BTG, and 10 BSV. The BTG was not automatically displayed; the executor had to import the seed phrase into a dedicated BTG wallet (Electrum for Bitcoin Gold) to see the balance.

Valuation. At the date of death, BCH traded at £250 per coin (£2,500 total), BSV at £50 per coin (£500 total), and BTG at £15 per coin (£150 total). The executor obtained a CoinMarketCap snapshot for each coin at the exact time of death (GMT). The total forked coin value was £3,150. This was added to the BTC value of £450,000, making the total cryptoasset holding £453,150.

IHT calculation. The total estate was £850,000 (house) + £120,000 (shares) + £453,150 (crypto) = £1,423,150. After the nil-rate band of £325,000 and the residence nil-rate band of £175,000 (assuming the house passes to direct descendants), the taxable estate was £923,150. IHT at 40% was £369,260. The forked coins contributed £1,260 of this liability. If the executor had omitted the forked coins, the IHT underpayment would have been £1,260, plus interest and a potential penalty.

The Role of Professional Appraisers and Specialist Wills

Given the complexity of forked coin valuation and the risk of HMRC challenge, executors should consider engaging a qualified digital asset appraiser for estates with significant crypto holdings. The STEP Digital Assets Special Interest Group publishes a directory of practitioners who have completed their Digital Assets Certificate, which covers valuation, tracing, and IHT reporting.

Specialist wills. For clients who hold cryptoassets, a standard will is often insufficient. A specialist will should include a “digital asset clause” that explicitly appoints a digital executor with the technical knowledge to access and value forked coins. Without this clause, the general executor may be forced to apply to the Probate Registry for directions on accessing the wallet, causing delay and cost. The Law Commission’s 2023 report on digital assets recommended that will draftsmen include such clauses as standard practice for any client with over £10,000 in cryptoassets.

Tax planning before death. A client who anticipates a future fork can mitigate IHT by gifting their cryptoassets more than seven years before death, or by transferring them into a trust. However, this triggers a Capital Gains Tax disposal at the market value of the original coin plus any forked coin that has already been claimed. Professional advice is essential before any such transfer.

FAQ

Q1: Do I need to report a forked coin on the IHT400 if it has zero market value at the date of death?

Yes, you should still disclose it in the “other assets” section of the IHT400 with a value of £0, accompanied by a brief note explaining the basis for the zero valuation (e.g., “No active market exists; no trading volume on any exchange in the 90 days preceding death”). HMRC may challenge this if the coin later gains value, but a contemporaneous disclosure protects the executor from a penalty for deliberate non-disclosure. The penalty for failing to disclose a zero-value asset that later becomes valuable can be up to 30% of the tax due on the subsequent gain, per HMRC’s penalty framework for incorrect returns.

Q2: How do I value a forked coin that is not listed on any UK-regulated exchange?

Use the price from the most liquid non-UK exchange that is accessible to UK residents, such as Binance or KuCoin, provided the exchange has a verifiable order book. Apply a liquidity discount of between 15% and 40%, depending on the spread and volume at the valuation date. Document the discount rationale in a written report. HMRC’s Cryptoassets Manual (CRYPTO30000) accepts the use of “reputable third-party price aggregators” like CoinMarketCap or CoinGecko, provided the executor can demonstrate the price is “open market” and not manipulated.

Q3: What happens if I cannot access the deceased’s hardware wallet to check for forked coins?

If the seed phrase or private key is lost, the forked coins are effectively inaccessible and should be valued at £0, with a full explanation on the IHT400. However, the executor must still search for any records of the wallet, including email receipts from exchange transfers, cloud backups, or written notes. If the wallet is later recovered after the IHT return is submitted, the executor must file an amended return within 12 months of discovery. HMRC will charge interest on the additional tax from the original due date, but penalties may be waived if the non-disclosure was not deliberate.

References

Law Commission of England and Wales. 2023. Digital Assets: Final Report (Law Com No 412).
HM Revenue & Customs. 2024. Cryptoassets Manual (CRYPTO20000–CRYPTO30000).
Society of Trust and Estate Practitioners (STEP). 2022. Digital Assets Global Guidance.
Bank of England. 2024. Daily Spot Exchange Rate Archive (for sterling conversion).
Chainalysis. 2023. The 2023 Crypto Crime Report (cited for HMRC analytics capability context).