Britain’s tax authority has released the first figures from its 2024-25 year, the first with a dedicated crypto box on the self assessment return. Two hundred and forty taxpayers each declared more than £1 million in crypto gains, £717 million between them. They make up under 2% of the 17,600 people who reported disposals, yet more than half the gains on record. Over the same window the tax office sent out 81,000 warning letters, a quarter more than the year before.
Key Takeaways
- 240 taxpayers each cleared £1 million in crypto gains, £717 million between them
- 17,600 people reported disposals in total, on £13.8 billion of proceeds and £1.38 billion of taxable gains
- 81,000 warning letters went out, against 65,000 the previous year
240 Filers Hold £717 Million of a £1.38 Billion Pot
This data did not exist in this shape until now. The 2024-25 tax year is the first where the UK return carries a line specifically for digital asset disposals, which finally allows the population to be measured rather than estimated.
The numbers sit in the release the UK government published on this new tax data. Seventeen thousand six hundred people reported taxable disposals, on £13.8 billion of proceeds and £1.38 billion of net gains.
Concentration is the headline finding. Two hundred and forty taxpayers each cleared a million pounds in gains, holding £717 million between them. They account for under 2% of filers and over half the gains.
The same concentration shows up in disposal proceeds, not just in gains. Those 240 taxpayers also account for more than half the £13.8 billion in amounts disposed of, which points to large positions rather than outsized returns on small volumes.
Converted into dollars, the totals read more familiarly for anyone tracking the market: $18.76 billion in proceeds, $1.87 billion in gains, $974 million of which belongs to the 240 filers at the top.
The average gain across the whole population lands at £78,000, roughly $106,000. That average is mechanically dragged upward by the 240 at the top, so it does not describe the median filer at all.
The rate schedule applied to crypto gains remains the standard capital gains one, 18% or 24% depending on the band, above a £3,000 annual allowance. Britain did not build a bespoke crypto regime, it filed the asset class into an existing frame.
That preference for attachment over exception shows up in the other UK calls of the moment. London pushed DeFi tax treatment back to 2027, having failed to settle how to classify transactions with no equivalent in existing law.
81,000 Warning Letters Went Out in a Single Year
The second strand of the release covers enforcement. The UK tax office wrote to 81,000 taxpayers it suspects of underreporting gains on digital assets.
The figure stood at 65,000 the year before, a quarter higher in twelve months. These letters are not assessments, they invite the recipient to correct their position before formal proceedings open.
The ratio between the two series is what makes the release worth reading. Seventeen thousand six hundred people filed voluntarily, against 81,000 letter recipients. The authority therefore believes the genuinely taxable population runs several times larger than the one declaring.
Britain is not moving alone here. South Korea will apply a 22% tax from 2027, after repeated delays that came down precisely to the absence of reliable data on the tax base.
For a UK tax resident the practical consequence lands right away. A dedicated box turns what used to be a loose declaration into an identifiable checkpoint, where a discrepancy becomes easy to spot and expensive to explain after the fact.
One methodological caveat belongs alongside those 81,000 letters. The authority sends them off cross-checks against data platforms already hand over on request, not off a systematic feed. The error rate on that kind of targeting has never been published.
Receiving one therefore proves nothing about actual underreporting. A holder who disposed below the £3,000 allowance, or who moved assets between their own wallets without realizing a gain, can surface in targeting built on gross movement.
The relationship between holders and British banks remains strained on separate grounds. Parliament opened an inquiry into account closures hitting the sector, a distinct issue from tax that touches the same population.
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Exchanges Will Hand Over Customer Data From 2027
The third element of the release looks forward and changes the nature of the exercise. From 2027, exchanges will have to pass their British customers’ data to the tax authority automatically.
The arrangement sits inside a reporting framework drawn up at the OECD and adopted across several jurisdictions. The principle mirrors the automatic exchange already applied to foreign bank accounts, transposed onto centralized crypto intermediaries.
The shift is structural. Until 2027 the tax office works from what people declare and what it manages to cross-check. After that it holds an inbound feed that makes the comparison between exchange-held positions and declared amounts automatic.
The limit lies in the perimeter. It targets intermediaries that hold customer accounts, meaning centralized platforms. Decentralized exchanges, peer-to-peer transfers and self-custody stay outside the automatic reporting scope entirely.
That asymmetry has already produced visible effects in Europe. Ten million Europeans were left without a compliant platform at the July MiCA deadline, and a share of those users moved to non-intermediated setups rather than switch provider.
The calendar leaves affected holders eighteen months. That is the window where correcting the record stays the taxpayer’s own move, before the gap becomes visible from both ends.
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