TL;DR: Yes. Coinbase has already shared UK customer data with HMRC, and from 1 January 2026 annual reporting becomes mandatory under the Cryptoasset Reporting Framework (CARF), with the first reports due by 31 May 2027. Coinbase is one of the few exchanges where this is a matter of public record rather than guesswork: back in 2021 it told a group of its own UK customers, directly, that it was passing their details to the tax office. If you have used Coinbase and not declared your gains or income, the time to act is now, while coming forward is still your decision rather than HMRC's.
This guide walks through what Coinbase has already shared, what CARF changes, where Coinbase sits with UK regulators, and the practical steps to take if you think you owe tax. It reflects HMRC, FCA and OECD positions as of June 2026.
Disclaimer
This guide is intended as a generic informative piece. This is not accounting or tax advice that can be relied upon for any UK individual's specific circumstances. Please speak to a qualified tax advisor about your specific circumstances before acting upon any of the information in this article.
Has Coinbase already shared my data with HMRC?
For most major exchanges, the honest answer to "do they share data with HMRC?" is "probably, but we cannot prove it". Coinbase is different. In 2021, Coinbase contacted a set of its UK customers directly to tell them their information was being passed to HMRC. Publicly reported Coinbase notices have referred to UK customers above a £5,000 threshold, though the exact scope varies by tax year and by the wording of each notice. HMRC had originally asked for a wider pull of customer data, and the reported scope was then narrowed.
HMRC did not gather this data for fun. It used the information to cross-check what people had declared on their tax returns, and to send letters to those whose returns did not line up. So if your Coinbase activity was above that £5,000 threshold around then, there is a real chance HMRC already holds a record of it.
HMRC's powers here are not new, and they are not specific to crypto. Under Schedule 23 of the Finance Act 2011 it can compel third parties to hand over bulk data, and under Schedule 36 of the Finance Act 2008 it can issue information notices about individual taxpayers.
What changes from 1 January 2026: the Cryptoasset Reporting Framework
The 2021 disclosure was a one-off legal request. It settled a question that had floated around crypto forums for years: yes, exchanges really do hand customer data to the tax office when asked. Useful to HMRC, but slow and reactive. What replaces it is something far more routine.
CARF, the Cryptoasset Reporting Framework, is the OECD's answer to crypto slipping through the cracks of international tax reporting. The UK adopted it domestically through The Reporting Cryptoasset Service Providers (Due Diligence and Reporting Requirements) Regulations 2025, which come into force from 1 January 2026. For a fuller explanation of the framework itself, see our earlier post on the OECD's release of CARF.
Instead of HMRC having to ask, qualifying exchanges will report UK customer data every year as a matter of course. It is the crypto equivalent of the Common Reporting Standard, the system that already swaps offshore bank-account information between more than 100 countries. CARF does the same job for crypto: it removes the gap that once let exchange activity sit unseen.
For a Coinbase user, the practical takeaway is simple. The 2021 disclosure showed HMRC was willing to go and get the data. CARF means it no longer has to.
What information will Coinbase report to HMRC under CARF?
For every UK-resident customer, a reporting exchange has to collect and report a defined set of details.
| Identity data | Transaction data |
|---|---|
| Full name | Transaction types (exchanges, transfers, spending) |
| Date of birth | Annual aggregate value |
| Home address | Units and asset type |
| Country of tax residence | - |
| National Insurance / UTR | - |
Those reports go to HMRC and are then shared with other tax authorities that have adopted CARF, so a UK resident using an overseas platform, or an overseas resident using a UK one, is still in scope. The rules carry real teeth for exchanges too: under HMRC's CARF guidance, a provider that files inaccurate, incomplete or unverified reports can face penalties of up to £300 per user, with further penalties for late filing.
When will HMRC start receiving Coinbase data under CARF?
| Date | What happens |
|---|---|
| 1 January 2026 | Data collection begins for in-scope exchanges with UK customers. |
| 31 May 2027 | First reports due to HMRC, covering 2026. |
| From 2027 onwards | International CARF data exchange with other countries begins. |
In practice, that means from the 2026/27 tax year onwards HMRC will be receiving an annual feed of reportable Coinbase activity to set against what you put on your Self Assessment return.
Is Coinbase legal and regulated in the UK?
This is where Coinbase stands apart from a lot of the exchanges people ask about. Coinbase's UK business, CB Payments Limited, is authorised by the Financial Conduct Authority as an electronic money institution under the Electronic Money Regulations 2011, and is registered with the FCA to carry out specific cryptoasset activities under the Money Laundering Regulations 2017 (firm reference number 900635). Being on the FCA's cryptoasset register is not a rubber stamp: only a small minority of the firms that have applied have made it on.
A couple of things are worth keeping straight. Being on the cryptoasset register means Coinbase has met the FCA's anti-money-laundering standards for crypto activities. It does not mean crypto itself is a regulated investment, and it does not mean your holdings are protected if their value falls. It also has no bearing on your tax position. Being regulated does not make Coinbase report any less to HMRC, and it certainly does not reduce what you owe.
Why has HMRC been sending nudge letters about crypto?
If HMRC thinks your declared income does not match the data it holds, one of the first things it does is send a nudge letter. This is not a formal investigation. It is a prompt asking you to check your tax affairs and put right anything you have missed, and it usually says HMRC has information suggesting you have crypto activity that was not declared.
The volume tells you how seriously HMRC is taking this:
- 2024/25 tax year: 64,982 nudge letters sent to people suspected of owing tax on crypto.
- 2023/24 tax year: 27,713
- Source: a UHY Hacker Young Freedom of Information request, reported by the Financial Times in October 2025.
These letters are generated from data matching, and Coinbase is one of the names HMRC has data on. A nudge letter is not an accusation, but ignoring one is the wrong move. People who correct their return after a nudge typically face lower penalties than those who wait for HMRC to open a formal enquiry. If a letter has landed on your doormat, our guide on what to do if you receive an HMRC nudge letter about your crypto takes you through it.
Can HMRC see my Coinbase transactions?
Not in real time, and not by logging into your account. HMRC does not get a live window into your Coinbase wallet. What it gets is data: the customer information Coinbase disclosed in 2021, the annual CARF reports that begin in 2026, and anything it requests through its information powers. HMRC then matches that data against what you declared on your return. So while nobody at HMRC is watching your trades as they happen, it can build a detailed picture of your Coinbase activity after the fact, which is more than enough to flag a return that does not add up.
Why Coinbase activity is easy to under-report
Coinbase is built to be beginner-friendly, and that is part of the problem at tax time. A lot of what happens on the platform is taxable without ever feeling like a trade.
- Rewards and interest pile up quietly. Staking rewards, Coinbase Earn and learning rewards, and USDC rewards all land in your account as income, valued at the moment you receive them. Each one is a separate taxable event even though you never pressed "sell".
- Spending crypto is a disposal. If you have used a Coinbase Card, every purchase is a disposal of crypto for capital gains purposes, not just a payment.
- Advanced Trade and legacy Coinbase Pro history. Coinbase's order-book trading now runs through Advanced Trade, which replaced Coinbase Pro. Long-standing users often have years of Coinbase Pro trades, conversions and transfers that have to be merged with their newer Coinbase activity to get a complete picture.
- Simple buys, sells and sends. Even the basic activity adds up across a few years, and transfers between your own wallets need to be matched so they are not mistaken for disposals.
Miss any of these and your numbers will not match what HMRC receives, which is exactly the mismatch that triggers a letter.
What should I do if I have undeclared Coinbase gains?
If you have used Coinbase and not declared your gains or income, the single most important thing is to come forward before HMRC contacts you. Voluntary disclosure almost always means a lower penalty than waiting to be found.
There are three steps.
1. Work out what you owe. You need a complete record of your Coinbase activity: every buy, sell, send, swap and card spend, plus everything you received as income such as staking rewards, Earn rewards and USDC interest. From that you calculate your capital gains using HMRC's share-pooling rules, explained in our comprehensive UK crypto tax guide, along with any income tax due on crypto you received. If you just want a quick estimate on a single disposal, our free crypto tax calculator will do the maths.
2. Tell HMRC. If the tax year is still open, you can amend your Self Assessment return online: the window runs for 12 months past the filing deadline, so a return filed by 31 January 2026 stays correctable until 31 January 2027. Once a year has closed to amendment, the route HMRC built for exactly this situation is the Cryptoasset Disclosure Facility, live since November 2023 for unpaid Income Tax or Capital Gains Tax on crypto.
3. Pay what is due. Interest is charged on late tax, and a penalty may apply too. Penalties are lower when you come forward before HMRC makes contact, so the earlier you move, the better the outcome tends to be.
Your own situation is something only a qualified accountant can properly advise on, and a good one will steer you through a disclosure and help keep the penalty down. You can find a Recap-verified UK crypto tax specialist on our directory.
One pattern we see a lot: people who carefully report their Coinbase sales but overlook years of staking rewards, Earn income and USDC interest entirely. Those rewards are taxable as income at their value on the day you received them, separate from any capital gain when you later sell. They are also the easiest thing to miss, because nothing about a reward landing in your account feels like a taxable event at the time.
How Recap helps with Coinbase tax
Recap connects to Coinbase and pulls your full history into one place, then classifies and values each transaction so you get a complete UK tax report. You can connect your Coinbase account via API for automatic syncing, or import your Coinbase transaction CSV if you prefer. Recap recognises the full range of Coinbase activity, from simple buys and sells to staking rewards, Earn rewards, USDC interest, Coinbase Card spends, Advanced Trade fills and legacy Coinbase Pro history, and it works out your gains and income using HMRC's rules.
Connect your Coinbase account to Recap and automatically calculate your UK crypto gains, income, and an HMRC-ready tax report you can file or share with your accountant.
References
- HMRC and OECD: Cryptoasset Reporting Framework, domestic reporting of UK-resident cryptoasset users
- HMRC: Implementation of the Cryptoasset Reporting Framework (penalties up to £300 per user)
- The Reporting Cryptoasset Service Providers (Due Diligence and Reporting Requirements) Regulations 2025
- Schedule 23, Finance Act 2011
- Schedule 36, Finance Act 2008
- HMRC Cryptoasset Disclosure Facility
- Nudge-letter statistics: UHY Hacker Young FOI, reported by the Financial Times, October 2025
- Coinbase 2021 UK data disclosure: publicly reported notices referred to UK customers above a £5,000 threshold; exact scope varies by tax year and notice wording. Press coverage, CoinDesk / Protos / Comsure, 2020 to 2021
- Coinbase UK FCA status: CB Payments Limited, FCA firm reference number 900635, authorised as an electronic money institution (Electronic Money Regulations 2011) and registered to carry out specific cryptoasset activities (Money Laundering Regulations 2017)
