Receiving a crypto tax notice from the Agencia Tributaria (AEAT) can be unsettling, especially if you are unsure why it arrived or how to respond. Many Spanish investors assume these notices are random, but in most cases, they stem from a mismatch between the AEAT’s data and the information declared on your tax return.
Spain’s tax authority now uses advanced systems and mandatory exchange reporting to monitor crypto activity. If you have received a notice, it means your transactions have triggered a review. The key is not to panic.
Understanding the notice type, acting quickly within deadlines, and maintaining proper documentation can make the process much smoother. With the right guidance, you can respond confidently and protect your crypto investments from costly penalties.
Understanding AEAT’s Crypto Surveillance System
Spain’s Agencia Tributaria (AEAT) has built one of the most comprehensive crypto surveillance systems in Europe. Its goal is to ensure that every taxpayer accurately reports crypto earnings, holdings, and transfers. The authority receives detailed transaction data directly from regulated exchanges and uses advanced data-matching tools to identify inconsistencies in declarations.
Domestic Reporting: Models 172 and 173
Spanish exchanges and custodians must submit annual reports detailing users’ activities. Model 172 captures the crypto balances held by users, while Model 173 records all operations such as purchases, sales, or swaps. The AEAT cross-checks these figures with what investors declare in their Modelo 100 (IRPF) filings. Any difference between reported activity and declared income can automatically trigger a crypto tax notice.
International Reporting: Modelo 721
If you hold cryptocurrencies abroad, you must declare them using Modelo 721 when the total value exceeds €50,000 at year-end. The AEAT uses this information to monitor offshore crypto holdings and prevent underreporting. Even if your assets are in cold wallets or foreign exchanges, failing to file Modelo 721 can lead to strict penalties and compliance investigations.
Future Compliance Under DAC8 Directive
The upcoming DAC8 Directive, expected to take effect in 2026, will expand data sharing among EU tax authorities. This means the AEAT will gain access to comprehensive transaction details from all European exchanges and custodians. Once implemented, even minor undeclared crypto activities within the EU will be visible to the AEAT, increasing the importance of transparent and timely reporting.
Also Read: How Is Cryptocurrency Taxed in Spain?
What To Do When You Receive A Crypto Tax Notice?
Receiving a tax notice from the AEAT requires quick and careful action. Every notice includes a strict deadline, usually between 10 and 15 working days, within which you must respond. Acting promptly ensures that you preserve your rights to appeal and prevents penalties from escalating.
Step 1: Record The Date Of Receipt
As soon as you receive the notice, note the official date of delivery (Acuse de Recibo). This date starts the countdown for your response period. Keep a digital and physical record of it. Missing this deadline means the AEAT can proceed with its decision without your input, which could result in automatic fines or enforced payments.
Step 2: Verify The Authenticity Of The Notice
Fraudulent tax messages have become common, so verifying the notice’s authenticity is vital.
Check the Secure Verification Code (CSV) printed on the document by visiting AEAT’s Sede Electrónica and using the “Cotejo de documentos con CSV” service.
A legitimate notice will match the AEAT’s database. This step ensures that you are responding to an official communication, not a phishing attempt.
Step 3: Access The Administrative File (Expediente)
Log in to the AEAT’s Sede Electrónica using your digital certificate, DNI electrónico, or Cl@ve PIN. Scroll to your expediente (administrative file) to view the complete details of the notice.
This file contains the AEAT’s reasoning, evidence, and the specific tax year involved. Reviewing this information carefully allows you to prepare your supporting documents and build an accurate response before submitting anything.
Types Of AEAT Crypto Tax Notices
Not all crypto tax notices from the Agencia Tributaria (AEAT) carry the same weight. Some are simple requests for clarification, while others indicate that the agency has already calculated a potential tax debt. Understanding the type of notice you receive helps determine the best way to respond and avoid penalties.
|
Notice Type |
AEAT’s Objective |
Legal Implication |
Required Action |
Standard Deadline |
|
Requerimiento de Información |
To gather missing details or supporting documents |
No debt yet; fact-finding stage |
Submit requested information and documents |
10 working days |
|
Propuesta de Liquidación Provisional (PLP) |
To confirm a calculated tax debt |
Debt is assumed unless contested |
Present evidence and submit Alegaciones (defence) |
10–15 working days |
How To Build A Strong Defence For Your Tax Notice?
Once you understand your notice type, the next step is to build a clear, well-documented defence. The Agencia Tributaria relies on strict evidence rules, especially when it comes to proving the acquisition value of your cryptocurrencies. A strong defence involves showing accurate records that establish when and how you acquired, traded, and held your digital assets.
Using The FIFO Rule For Proof
Spain mandates the FIFO (First In, First Out) method for calculating capital gains and losses from crypto. This means the first tokens you purchased are considered the first ones you sold. Consistently applying this rule helps verify your cost basis and gain calculation. Errors in FIFO reporting are among the most common reasons AEAT notices are issued, so maintaining accuracy here is essential.
Essential Documents For Defence
To prove your cost basis and ensure an accurate response to the AEAT, you must present verifiable documents. These records demonstrate both the acquisition and sale of your cryptocurrencies. Key documents include:
- Bank statements confirming the transfer of fiat funds into crypto exchanges.
- Exchange purchase logs (CSV files) with transaction dates, values in euros, and applicable fees.
- FIFO reconciliation reports matching each sale to its corresponding purchase lot.
- Permuta (crypto-to-crypto swap) valuations showing market value differences.
- Foreign exchange statements (if applicable to Modelo 721) confirming end-of-year balances.
These proofs create an unbroken audit trail that aligns with AEAT expectations, ensuring every transaction is properly accounted for.
Responding To Modelo 721 Omissions
If your notice relates to Modelo 721, it likely concerns undeclared crypto holdings abroad worth over €50,000. In this case, submit documentation from foreign exchanges or custodians confirming your asset values as of December 31st. If your holdings were below the threshold or stored in exempt wallets, present that evidence clearly to avoid fines.
Submitting a Proper Response To Your Tax Notice
Responding correctly to the AEAT is just as important as preparing your defence. Spain’s tax system now requires all crypto-related submissions to be filed electronically. Ensuring that your response follows the AEAT’s procedures prevents delays, rejections, or potential fines.
Preparing The Escrito de Alegaciones
Your response should take the form of an Escrito de Alegaciones (written defence). This document must clearly state your administrative file number (expediente), the type of notice received, and the act being challenged. It should include:
- A brief summary of the issue.
- A detailed explanation of why the AEAT’s assessment is inaccurate.
- Supporting documents proving acquisition value, transaction history, and applicable FIFO calculations.
The goal is to present factual evidence that disproves the AEAT’s assumptions, such as a zero-cost basis or missing declarations.
Filing Through Sede Electrónica
All crypto tax responses must be submitted through the AEAT’s Sede Electrónica. You can access this platform using your DNI electrónico, digital certificate, or Cl@ve PIN.
- Choose the “Contestar requerimientos y presentar documentación” option to upload your response and attachments.
Make sure your files are clearly labelled and that every reference matches your expediente number.
Appointing A Legal Representative
If you prefer to have a tax professional or lawyer manage your response, you can grant them legal authority using the Apoderamientos system on the Sede Electrónica.
This registration gives them permission to access your confidential records and submit documents on your behalf. Appointing a qualified representative ensures that your defence is properly structured and filed before the deadline.
Can You Correct Past Taxation Errors In Spain?
Sometimes, a crypto tax notice from the AEAT reveals a genuine mistake or omission in your previous filing. In such cases, correcting the error promptly can significantly reduce penalties and protect your financial record. Spain’s tax framework allows voluntary corrections that are less severe than enforced ones, so acting early is always beneficial.
Amending Income Tax Returns (Modelo 100)
If you discover an error in your income tax return related to undeclared crypto gains, you can submit a Declaración Complementaria to add the missing data. However, if the mistake resulted in overpayment, you must file a Rectificación de Autoliquidación instead. Voluntary corrections submitted before the AEAT issues a formal notice to avoid fines and only attract minor surcharges calculated monthly.
Amending Informative Declarations (Modelo 721/720)
Errors or omissions in informative forms such as Modelo 721 must be corrected by filing a Declaración Sustitutiva. This replaces the earlier incorrect version and references the original declaration number. Filing this voluntarily, even after the deadline, can substantially reduce the risk of receiving severe fines for incomplete or missing foreign crypto disclosures.
Penalty Mitigation Through Voluntary Action
Spain’s tax laws reward transparency. If you correct your filings before the AEAT formally intervenes, you avoid penalties and instead pay a progressive surcharge. This surcharge increases gradually depending on how late the correction is filed.
How KoinX Helps You Avoid AEAT Crypto Notices?
Managing Spain’s crypto tax requirements can be challenging, especially with the Agencia Tributaria’s strict monitoring and reporting systems. Errors in FIFO calculations, missed deadlines, or incomplete transaction records can easily trigger tax notices. This is where KoinX simplifies everything. It automates your reporting process, keeps every transaction audit-ready, and ensures you always stay compliant with Spanish tax laws.
Automatic Integration Across 800+ Platforms
KoinX connects seamlessly with over 800 exchanges and wallets, automatically fetching your transaction data in real time. This eliminates manual data entry and ensures your reports always reflect accurate and up-to-date information.
Accurate FIFO-Based Tax Calculation
The platform applies Spain’s mandatory FIFO method to calculate your gains and losses precisely. It also detects and categorises disposals, swaps, and staking rewards, helping you avoid reporting errors that might attract AEAT scrutiny.
AEAT-Ready Tax Reports
KoinX generates detailed, Spanish-compliant tax reports tailored for models like Modelo 100 and Modelo 721. These reports align perfectly with AEAT filing requirements, making submission smoother and more reliable.
Comprehensive Audit Trail
Every report includes a clear record of your acquisition costs, trade history, and asset values, giving you a complete audit trail. This documentation can serve as solid evidence in case of AEAT reviews or requests for clarification.
Using KoinX not only saves you time but also prevents costly mistakes. Join KoinX today to automate your crypto tax filing, stay compliant with AEAT rules, and protect your peace of mind throughout the Spanish tax season.
Conclusion
Receiving a crypto tax notice in Spain does not always mean you have done something wrong. It simply signals that the Agencia Tributaria needs more clarity on your crypto activity. What matters most is how quickly and accurately you respond. Keeping detailed records, applying the correct tax rules, and filing within deadlines can help you resolve the issue smoothly.
To simplify compliance, use KoinX, a reliable platform that automates your calculations, generates Spanish-compliant reports, and helps you avoid AEAT scrutiny. Sign-up on KoinX today to take control of your crypto taxes and stay fully prepared for Spain’s evolving digital tax environment.
Frequently Asked Questions
What Should I Do If I Miss The AEAT Response Deadline?
If you miss the deadline, the AEAT may finalise your case without your input, resulting in automatic fines. You can still file an appeal or request a review, but it is always best to respond promptly within the 10–15 working-day window.
Can Non-Residents Receive Crypto Tax Notices In Spain?
Yes, non-residents who hold or trade crypto assets connected to Spanish exchanges or financial institutions can also receive AEAT notices. They must comply with Spanish tax obligations on income or assets derived from within Spain.
How Long Should I Keep My Crypto Records For AEAT Audits?
You should retain all crypto transaction records for at least five years. This includes exchange reports, purchase receipts, and wallet transfers. The AEAT may request these records during audits to verify your tax declarations and ensure compliance.
Can I Appeal A Final AEAT Decision On My Crypto Taxes?
Yes, you can appeal through Spain’s administrative or judicial channels if you disagree with a final AEAT decision. However, you must file the appeal within the specified timeframe mentioned in your notice, typically within one month.
Does The AEAT Consider Crypto Swaps As Taxable Events?
Yes, the AEAT classifies crypto-to-crypto swaps as taxable disposals under Spain’s permuta rule. This means each trade creates a potential capital gain or loss that must be reported in your annual tax return.
What Happens If I File My Modelo 721 Incorrectly?
Filing Modelo 721 with incorrect or incomplete information can result in severe penalties, including fines starting at €200 per error or €5,000 per undeclared crypto set. Reviewing the data carefully before submission helps prevent costly mistakes.
