HMRC's first crypto tax data reveals a market dominated by 240 whales

Here's the thing about the UK crypto market: it's not a retail revolution. It's a whale economy wearing a retail disguise.

HMRC just published its first-ever crypto Capital Gains Tax data. The headline number is £1.38 billion in declared gains across 17,600 taxpayers for the 2024-25 tax year. But dig into the breakdown and the picture gets uncomfortable. A mere 240 individuals reported gains of £1 million or more. Together, they accounted for over half of all declared gains. Let me break this down: that's 1.4% of filers controlling roughly 50% of the reported wealth. The other 17,360 people split the rest.

The median gain lands somewhere between £10,000 and £20,000. That's a meaningful sum, sure. But it's not life-changing money. The reality is that most UK crypto investors are playing with position sizes that would make a Goldman desk laugh.

What the numbers actually tell us

This data matters for two reasons. First, it's a baseline. HMRC has never published crypto-specific CGT data before. Second, it's the last time the agency will rely on voluntary declarations for its market view. The OECD's Crypto-Asset Reporting Framework (CARF) comes online this year, with the first data reaching HMRC in 2027. That means exchanges and custodians will start handing over transaction data directly. No more guessing games.

For context, the 2024-25 figures capture a period when Bitcoin traded between roughly $40,000 and $120,000. It was a strong year. The fact that only 17,600 people bothered to declare crypto gains is itself a story. Estimates put UK crypto ownership in the millions. If most holders never sold, fine. But anyone who tells you that's the whole explanation is selling something.

The gap between what's declared and what's actually held is the untold risk here.

The counterpoint: maybe the whales aren't the problem

Let's steelman the other side. One could argue this concentration is just the natural outcome of early adoption. Bitcoin and Ethereum were cheap a decade ago. A modest early position in BTC at $3,000 is now a life-changing amount of money. The 240 whale filers might simply be the old guard who got in before the crowd. Nothing sinister about that.

There's also a compliance angle. HMRC's new reporting regime is coming, and that will force more accurate disclosure. The 2024-25 data is the last snapshot of an era. From that view, the concentration we're seeing won't persist. CARF data will reveal a broader base, or at least that's the hope.

But here's what the street is missing: the concentration itself is a signal. A market where 1.4% of taxpayers hold 50% of gains isn't a healthy retail market. It's a market with institutional fingerprints, or a handful of early miners and traders who never diversified. And when CARF data surfaces, it's going to show that the UK's tax net captured a fraction of the real activity.

My verdict: the 2027 data dump will be brutal

I'm not going to hedge here. This data is the opening act. When CARF begins delivering exchange-level transaction data in 2027, we're going to see declared gains that dwarf this £1.38 billion figure. The 17,600 filers will look like a rounding error.

That's not a criticism of HMRC. It's a criticism of an asset class that grew up outside traditional reporting rails. The UK has done more than most to bring crypto under regulatory oversight, but the enforcement gap has been glaring.

The real question is what happens next. Do we see a wave of voluntary disclosures between now and 2027? Or do investors wait, hope for the best, and risk penalties? From a risk perspective, the rational move is to clean up your position now. But rationality has never been this market's strong suit.

The numbers tell the story. £1.38 billion in declared gains. 240 people. One tax year. And the full picture hasn't even arrived yet. That's what makes this baseline so important. It's the last time HMRC will see only what people choose to report. After 2027, it sees everything. Buckle up.