Why the dates matter
CARF, DAC8 and the UK HMRC regime are all built around the same operational rhythm: collect transaction-level data over a calendar year, aggregate it, validate it against an XML schema, submit it to a tax authority in the months following year-end. Where they differ is in the precise deadlines, and missing a deadline is not a paperwork problem, it is a penalty exposure.
For most CASPs the practical impact is that CY2026 is the first data year for which they will file under one or more of these regimes, with the first filings due between May and September 2027 depending on jurisdiction.
The timeline
OECD publishes CARF
The OECD's Crypto-Asset Reporting Framework is released in October 2022, alongside amendments to the CRS extending it to certain stablecoins and CBDCs.
EU adopts DAC8
Council Directive (EU) 2023/2226 is adopted on 17 October 2023, making CARF mandatory across the 27 EU member states.
Early adopter consultations
New Zealand, the UK, Austria and others run public consultations on domestic implementation. The OECD publishes CARFxml v1.5 with TIN validation rules.
DAC8 transposition deadline
EU member states must transpose DAC8 into national law by 31 December 2025. Many publish draft implementing legislation through Q3 and Q4.
First reporting period begins
CY2026 is the first reportable year for CARF early adopters, DAC8, and the UK HMRC regime. Transaction data collection begins 1 January 2026.
First filings due
HMRC: 31 May 2027. EU DAC8: 30 September 2027 (Sweden 1 April 2027). CARF (most early adopters): 30 September 2027.
First international exchanges
Tax authorities exchange the 2026 data among themselves under bilateral and multilateral competent authority agreements.
US joins
The United States targets CARF participation from CY2028 onward, with first exchanges in 2029 leveraging Form 1099-DA infrastructure and FATCA-style reciprocity.
What to do, quarter by quarter
Q3 2026, Data integrity checks
Halfway through the first reporting year, run a data quality audit on the year-to-date position. Check TIN coverage by jurisdiction, missing self-certifications, and the completeness of cost-basis data on reportable transactions. Anything you cannot fix retroactively (missing TINs, ambiguous residence) is much cheaper to chase users for in Q3 than in Q1 next year.
Q4 2026, Schema lockdown and dry runs
Lock the schema version your CARF generator targets (CARFxml v1.5 unless the OECD publishes a v1.6 in time). Generate a dry-run XML for the year-to-date dataset and validate against the XSD. Submit a sandbox test file to any tax authority that offers a test channel (HMRC, IRD, BMF in Germany).
Q1 2027, User remediation window
The 60-day self-certification rule means any user with an outstanding certification at year-end must be reminded, reminded again, and ultimately blocked from transacting if they do not respond. Q1 is the window to close out as many of these as possible before the file is generated.
Q2 2027, File and submit
- HMRC: register, generate, validate, submit by 31 May.
- DAC8 (single MS): file by 30 September, or 1 April in Sweden.
- CARF early adopters: deadlines from 30 June (NZ) through 30 September.
Further reading
- OECD CARF FAQs (December 2025)
- HMRC, Cryptoasset Reporting Framework: Implementation Guide
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