Your crypto exchange is asking for your National Insurance number because the Cryptoasset Service Providers (Due Diligence and Reporting Requirements) Regulations 2025 require it. The rules commenced on 1 January 2026. Every platform serving UK users must now collect your tax number, address and country of tax residence, then report it to HMRC each year.
Those regulations bring the OECD Cryptoasset Reporting Framework, or CARF, into UK law. Think of it as the Common Reporting Standard that banks already follow, extended to crypto. Your exchange calls the form a self-certification, and the number it wants is your Taxpayer Identification Number. In the UK, that means your National Insurance number, or your UTR if you file Self Assessment.
So the request is genuine, and refusing it will not help. Coinbase, Binance, Kraken and Revolut all send the same message, because they follow the same rulebook. But you should still know what happens to your data, and how to spot the phishing scams copying it.
Crypto Accountants works on cryptoasset tax full-time, and our Managing Partner, Malik Ali, FCCA, leads the team advising crypto investors on HMRC disclosures and enquiries.
Wondering what HMRC will actually see? Book a call with Crypto Accountants, and we will review your exchange history with you.
What Data Your Crypto Exchange Must Collect Under CARF?
The prompt usually appears when you log in. It asks you to confirm your legal name, date of birth, home address, the country where you pay tax, and a tax reference number.
For a UK resident, that number means your National Insurance number, or your Unique Taxpayer Reference if you file a Self Assessment return.
Exchanges call this a self-certification. In plain terms, you tell the platform where you are taxed, and the platform is putting your name to a file it must hand over later. So a crypto exchange asking for your National Insurance number is not doing extra due diligence of its own. It is filling in a form that HMRC will read.
Coinbase, Binance, Kraken, Revolut, Crypto.com and the smaller platforms all send some version of this message. They are not copying each other, but following the same rulebook.
What changed on 1 January 2026?
The UK adopted the Cryptoasset Reporting Framework, a global standard written by the OECD. The rules commenced on 1 January 2026.
From that date, crypto service providers operating in the UK must identify their users properly and record their transactions. They then send an annual report to HMRC.
The first report covers the 2026 calendar year and reaches HMRC by 31 May 2027, and a fresh report follows every year after that.
The rules also bite on the platforms themselves. A provider that fails to collect and report user data correctly faces penalties of up to £300 per user.
Multiply that across a customer base of a few hundred thousand people, and you can see why the pop-up keeps appearing every time you open the app.
Every crypto exchange asking for your National Insurance number right now is protecting itself, not testing you. Your platform has more to lose than you do.
Why Does Binance Want My Tax Residency in the UK?
Binance asks about tax residency for the same reason, but the question does extra work for a platform that operates worldwide.
Your tax residency decides which tax authority receives your file. If you tell Binance you are a UK resident, your data goes to HMRC.
If you say you are a Spanish resident, it goes to the Spanish authority instead, and equivalent EU rules push it along the same track.
Reporting also runs both ways, so a UK resident using a platform based in Ireland or Malta still ends up in HMRC’s file. The data simply travels through the local authority first.
Binance therefore sits alongside every other crypto exchange asking for your National Insurance number or its local equivalent. That is also why “I only use an overseas exchange” no longer keeps anything private.
More than 70 jurisdictions have signed up for the CARF, and they exchange the reports with each other.
Is it Safe to Give Your National Insurance Number to a Crypto Exchange?
Yes, when the request is real. Your exchange already holds your passport or driving licence from its original identity checks, so a National Insurance number adds little extra risk on top of what it stores today.
Scammers know about the new rules, though, and they have started copying the message. So check before you type anything.
How to Spot a Fake Request?
Never respond through a link in an email or a text. Instead, close the message, open the app or type the exchange’s website address yourself, and look for the same prompt inside your account. A genuine self-certification always lives in your account settings.
Then apply three simple tests. A genuine crypto exchange asking for your National Insurance number never asks for your password, seed phrase or private keys alongside it, because it has no use for any of them. A real request never asks you to move funds to a “verified” wallet. And a real request never threatens to seize your crypto within 24 hours.
If a message fails any of those tests, it is a phishing attempt. Report it, delete it, and check the FCA’s Scam Smart guidance.
What Happens If You Refuse to Give the Number?
You lose access to the parts of the account you care about.
A crypto exchange asking for your National Insurance number cannot skip the requirement if you say no, so it applies pressure instead. Most start with reminders, then restrict your trading or your withdrawals, and eventually freeze the account until you complete the form. Some close accounts outright. Meanwhile, the platform still reports what it holds about you, just flagged as incomplete, which draws more attention rather than less.
Providing false details makes things worse.
Giving a made-up number or claiming residency in a country where you do not live carries its own penalty under UK regulations. It changes the picture from a paperwork error into something deliberate.
What Does HMRC Do with the Information?
HMRC matches it. That is the whole purpose.
Your reported crypto data goes into the same system that already holds your employment records, your bank interest, your rental income and your tax returns. HMRC then compares the crypto file against what you declared. Where the two do not agree, HMRC generates a letter, and it does that automatically rather than case by case.
You can see the shape of this already. HMRC sent roughly 65,000 nudge letters to crypto investors in 2024/25, up from about 27,700 the year before, and that happened using data HMRC had to request.
Automatic annual reporting gives it far more to work with.
What if your details do not match, or you have older activity?
Two situations come up constantly, and both deserve a calm response rather than a panicked one.
The first is a simple mismatch. Your exchange holds an old address, a maiden name, or a different date of birth from the one HMRC has. That kind of gap creates a report HMRC cannot match to a taxpayer, and unmatched reports get looked at by a human. Fix the details in your account now, before the annual report goes out, because correcting it afterwards takes far longer.
The second situation is trickier. Plenty of people realise, while filling in this form, that they never declared gains from 2021 or 2022. Swapping one coin for another counts as a disposal in the UK, so a run of token trades can create a real tax bill even if you never withdrew a pound to your bank.
If that describes you, the timing works in your favour right now. HMRC treats a disclosure you make voluntarily far more kindly than one it has to chase, and the penalty on an unprompted disclosure often comes out at nil.
Once HMRC writes to you first, that option narrows.
Get Your Crypto Records Right Before 31 May 2027!
Answer your crypto exchange asking for your National Insurance number through the app itself, not through any link you were sent. Check that your name, address and date of birth match your official records exactly. Then download your full transaction history from every platform you have used, because the 2026 calendar year is the first one HMRC will see in full.
If that history contains anything you have not reported, deal with it now while the choice is still yours.
Not sure whether your past crypto activity leaves you exposed? Book a call with Crypto Accountants or ring 0208 638 5800.
We will review your history and tell you where you stand.
People Also Ask
My exchange asked for my National Insurance number – why?
Because UK law requires it. Since 1 January 2026, crypto platforms must collect your tax number, address and country of tax residence, then report that data to HMRC every year. Complete the request inside the app, not through an emailed link.
Do I have to give my crypto exchange my National Insurance number?
Yes, if you want to keep using the account. The platform cannot skip the rule, so it will restrict your trading or withdrawals until you complete the form.
Is it safe to give my National Insurance number to a crypto exchange?
Yes, when the request comes through the app or official website. Never respond to a link in an email or text, and never give a seed phrase or password alongside it.
Does giving my National Insurance number mean I will get a tax bill?
Not by itself. It just lets HMRC match your crypto activity to your tax record. If you reported your gains correctly, nothing changes.
Why does Binance want my tax residency?
Your tax residency decides which authority gets your data. Say UK, and it goes to HMRC. Binance operates worldwide, so it has to ask before it can file anything.
Can I refuse and move to a different exchange?
No. Every platform serving UK users follows the same rules, and more than 70 countries have signed up to the framework. Moving overseas does not help.
