How to keep records of your crypto operations
The AEAT may require documentation of your crypto operations for the last 4 years (or up to 10 in serious cases). Having the documentation correctly organized can be the difference between a check that closes quickly and a long and costly inspection.
What documentation should you keep?
From exchanges (CEX)
- Full historical statement of all operations (CSV or PDF) with: date, type of operation, pair, quantity, unit price, fee.
- Deposit and withdrawal history: with transaction hashes.
- Screenshots of the balance as of December 31 of each year.
- KYC documentation: confirmation of your account with the exchange.
From own wallets
- List of all wallets (public) owned by you.
- Transaction history of each wallet (exportable from blockchain explorers or tools like Koinly, CoinTracking…).
- Proof of purchase of hardware wallets (Ledger, Trezor…).
From DeFi operations
- Transaction hashes of each on-chain operation.
- Screenshots and records of positions in DeFi protocols (Aave, Uniswap…).
- Claim history of rewards or airdrops.
From P2P operations
- Chat or confirmation from the P2P platform.
- Payment receipt (bank transfer, PayPal, etc.).
- In-chain transaction hash of the crypto sending/receiving.
In what format to keep them?
- CSV downloaded directly from the exchange when still possible: some exchanges delete history after a certain time.
- PDF/screenshots as backup.
- Tax software export (Koinly, TaxDown, declaracrypto…) that generates the already calculated report.
- Cloud backup (Google Drive, iCloud, Dropbox) plus local copy.
How long to keep them?
| Situation | Minimum time |
|---|---|
| General | 4 years |
| If there is fraud or concealment | 10 years |
| Practical recommendation | 10 years |
The 4-year statute of limitations begins to count from the last day of the deadline for filing the tax return for the year in question.
The risk of exchanges that disappear
If the exchange closes, you lose access to the history. Always download the full CSV periodically (at least every year) and save it offline.
Conclusion
Documentation is your first line of defense against any AEAT requirement. Invest 30 minutes a year in downloading and organizing statements from all your exchanges. If you use a tax tool like declaracrypto, the generated report is an excellent starting point for documentation.