What is DAC8?
The Directive on Administrative Cooperation 8 (DAC8) is an EU directive that mandates automatic exchange of crypto-asset transaction data between member state tax authorities. It ensures that when a Spanish tax resident trades crypto on a platform registered in another EU country, Spanish tax authorities (AEAT) receive that transaction data automatically.
DAC8 builds on the global OECD Crypto-Asset Reporting Framework (CARF) and extends it with EU-specific requirements. The implementation deadline is September 30, 2027, but Spain has already implemented key elements through the Modelo reporting system.
The three Modelo filings for crypto
Spain requires three distinct informational tax declarations for crypto-assets. Each serves a different purpose and applies to different entities.
Reports crypto-asset balances held by third parties. If you operate a platform that custodies client crypto, you must declare every client's holdings as of December 31 of the preceding year, including asset type, quantity, and EUR equivalent value.
Reports all crypto-asset transactions performed through your platform during the fiscal year. Every buy, sell, swap, and transfer must be declared with EUR equivalent values at the time of execution, counterparty details, and transaction type classification.
Declares crypto-assets held on foreign platforms. Any Spanish tax resident holding crypto-assets abroad (on non-Spanish platforms) with a total value exceeding €50,000 must file this declaration. Once filed, subsequent years only require filing if holdings increase by more than €20,000.
Who must file each Modelo?
| Modelo | Filed by | Applies when |
|---|---|---|
| 172 | Platforms, exchanges, custodians operating in Spain | You hold any client crypto-assets |
| 173 | Platforms, exchanges, intermediaries operating in Spain | Any client performs crypto transactions through your platform |
| 721 | Individual Spanish tax residents | You hold >€50,000 in crypto on foreign platforms |
If you operate a crypto exchange or custody service in Spain, you must file both Modelo 172 and 173. These are platform-level obligations — your individual clients do not file these forms. However, your clients may need to file Modelo 721 separately if they also hold assets on foreign platforms.
XML schema requirements
All Modelo filings must be submitted electronically to AEAT in machine-readable XML format. The XML schemas are defined by AEAT and include strict validation rules:
- All monetary values must be in EUR with exactly 2 decimal places
- Asset identifiers must use standardized codes (ISO or AEAT-defined)
- Transaction timestamps must include timezone information
- Client identification requires NIF/NIE for Spanish residents or passport/foreign ID for non-residents
- Platform identification requires legal entity identifiers and CIF/NIF
Manual preparation of these XML files is error-prone and impractical at scale. SENTINEL's Reporter agent generates schema-compliant XML for all three Modelo filings automatically.
Filing deadlines calendar
| Filing | Covers | Deadline | Urgency |
|---|---|---|---|
| Modelo 721 | Foreign holdings FY 2025 | 31 Mar 2026 | 10 days |
| Modelo 172 | Client balances FY 2026 | 31 Mar 2027 | 375 days |
| Modelo 173 | Client transactions FY 2026 | 31 Mar 2027 | 375 days |
Penalties for non-filing
Failure to file or late filing of any Modelo declaration carries significant penalties under Spanish tax law:
- Late filing (voluntary): Reduced penalties if filed before AEAT notification, typically €100–€400 per declaration
- Late filing (after notice): €200 per data item with a minimum of €300 and maximum of €20,000 per filing
- Non-filing: Additional surcharges of 5–20% on undeclared amounts, plus daily interest
- Modelo 721 specifically: Previously carried disproportionate penalties that were ruled unconstitutional — current penalties align with standard late-filing charges
SENTINEL tracks every transaction, classifies it according to MiCA and DAC8 categories, computes EUR equivalents at settlement price, and generates submission-ready XML for Modelo 172, 173, and 721. Priority deadline alerts ensure you never miss a filing window. Plans start at €99/month.
DAC8 timeline for Spain
While the Modelo filings are already in effect, DAC8's full automatic exchange mechanism has its own timeline:
- January 1, 2026: CASPs begin collecting reportable information under DAC8 rules
- September 30, 2027: Member states begin automatic exchange of crypto transaction data
- 2028 onwards: Annual automatic exchange of prior-year crypto transaction data between all EU member states
This means that even if you trade crypto on a platform in Estonia, France, or Germany — AEAT will receive your transaction data automatically from 2027 onwards. Voluntary compliance now is significantly better than forced compliance later.
Next steps
If you're a Spanish crypto trader or operate a CASP in Spain, start by understanding which Modelos apply to your situation. Read our guide on MiCA licensing requirements before July 2026, or check our FAQ for answers to common compliance questions.