# CARF reporting hub — what UK crypto firms send HMRC

In-scope cryptoasset service providers collect customer and transaction information from 1 January 2026. The first UK reports cover calendar year 2026 and are due by 31 May 2027. HMRC also receives information through international exchange. CARF does not calculate your liability or replace your own tax return.

## Key facts
- CARF uses calendar years; Self Assessment uses UK tax years.
- The first UK reports are due by 31 May 2027 for 2026 activity.
- Provider reporting does not replace your own calculation or return.
- Overseas providers may report through their own jurisdiction.
- Self-custody does not remove tax obligations or make transfers invisible.

## Which UK firms must report under CARF

Reporting status depends on the provider’s activities and UK connection under the CARF rules. FCA registration is not the test by itself. Providers should use HMRC’s reporting guidance; a user should expect identity and tax-residence checks and retain their own records.
## What data providers collect from you

Expect requests for legal name, address, date of birth, tax identification (NINO where UK-resident), and confirmation of tax residence. For entities: company number and controlling persons. Providers must keep this accurate — update your profile after moving home or changing name.
## What gets reported to HMRC

Providers report identifying information and prescribed transaction information, including aggregates by cryptoasset and transaction category. A transfer to a personal wallet may appear in provider records without itself creating a taxable disposal. Reconcile the underlying events rather than treating reported gross values as taxable profit.
## Timeline: 2026 to 2028

1 January 2026: data collection begins. Throughout 2026: providers log reportable transactions. By May 2027: first CARF reports submitted to HMRC for calendar 2026. 31 January 2028: your online Self Assessment deadline for tax year 2026/27 — align your records with what providers reported.
## Self-custody, DeFi and foreign exchanges

HMRC can receive information from overseas reporting jurisdictions as well as UK providers. A self-hosted wallet does not remove tax obligations; transfers between providers and that wallet can leave an evidence trail. DeFi arrangements need their own tax analysis. Keep the full history wherever you transact.
## If your return does not match CARF data

HMRC may open enquiries if declared gains differ materially from provider reports. Keep CSV exports, software audit trails and wallet logs. Correct errors via amended return or disclosure service before HMRC contacts you.

Start by [rebuilding and reconciling the transaction history](https://digital-assets.co.uk/tax/crypto-missing-cost-basis/) so each difference can be explained.
## Consumer rights and privacy

Providers must explain CARF in privacy notices. You cannot opt out of statutory reporting by closing an account if transactions already occurred. GDPR still applies to how firms store your data.

## Visual explanation
Two reporting clocks
CARF. 1 Jan → 31 Dec: Provider reporting follows the calendar year.
UK TAX. 6 Apr → 5 Apr: Individual tax records follow the UK tax year.
Keep both date ranges in your records. Provider reporting does not replace your own calculation or return.

## FAQs
### Will CARF tell me how much tax to pay?

No. CARF is information exchange. You calculate tax using pooling rules and file Self Assessment.
### I only use a hardware wallet — does CARF affect me?

Self-custody does not exempt you from tax. A provider can report transfers involving your wallet, and overseas information may reach HMRC through exchange arrangements.
### What if I forgot to declare old years?

Check HMRC’s cryptoasset disclosure service and the applicable correction route. The outcome depends on the facts, timing and behaviour; voluntary disclosure does not guarantee a particular penalty.

## Sources

- [HMRC: reporting service-provider guidance](https://www.gov.uk/government/collections/reporting-to-hmrc-if-you-provide-cryptoasset-services-in-the-uk)
- [HMRC: domestic and international reporting](https://www.gov.uk/government/publications/cryptoasset-reporting-framework-reporting-of-uk-resident-cryptoasset-users/domestic-reporting-of-uk-resident-cryptoasset-users-under-the-cryptoasset-reporting-framework)
- [CARF reporting regulations 2025](https://www.legislation.gov.uk/uksi/2025/744/contents)

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— Digital Assets UK (https://digital-assets.co.uk/tax/carf-reporting-hub/), reviewed 2026-09-30. Source: https://www.gov.uk/government/collections/reporting-to-hmrc-if-you-provide-cryptoasset-services-in-the-uk