Hard forks, gifts and lost crypto — UK tax treatment
Quick answer: A hard fork normally requires the original allowable cost to be apportioned between the resulting token pools. Ordinary gifts generally use market value; qualifying spouse or civil-partner transfers have different rules. Theft or loss of a private key is not itself a disposal.
Unusual events — forks, presents, hacks — still have tax rules. This guide covers the scenarios HMRC addresses in the Cryptoassets Manual.
Hard forks and chain splits
Following a hard fork, put the new tokens in their own Section 104 pool. Split the original allowable costs between the old and new pools on a just and reasonable basis. Retain the valuation and apportionment method; exchange recognition of the new token can affect the facts.
Gifting crypto
For an ordinary gift, the donor generally disposes at market value and the recipient generally acquires at that value. Qualifying spouse or civil-partner transfers use no-gain/no-loss treatment instead. Gifts to charities and other reliefs have separate conditions; do not apply one cost-basis rule to every gift.
Lost keys and theft
Neither losing a private key nor theft is itself a disposal. If there is no prospect of recovering a key or accessing the tokens, HMRC may accept a negligible-value claim. Theft alone does not support a CGT loss; a police report does not change that tax treatment.
The negligible-value guide separates lost access, theft and claims involving worthless tokens.
Frequently asked questions
Is giving crypto to charity taxable? +
Gifts to UK charities may qualify for CGT relief in some cases — see HMRC charitable giving guidance.