With more Belgians diving into crypto trading, the tax office is now paying closer attention to digital assets than ever before. As per Statista, the crypto market in Belgium can reach up to $620 million in 2025. So, if you’re investing, trading, or earning income in crypto, there’s a growing chance your activity could trigger a tax audit.
But why a tax audit? Even honest mistakes or missing records can raise questions. The Federal Public Service (SPF) has tools to flag inconsistencies and will investigate further if anything seems off. That’s why it’s important to understand exactly what draws their attention.
In this guide, we’ll walk you through the red flags that matter most, how long audits can last, and how to stay ahead of any inspection. Let’s help you avoid surprises and stay on the right side of Belgian tax law.
Red Flags That Can Trigger a Crypto Audit in Belgium
Even if you file your taxes on time, certain crypto-related activities can still raise red flags with the Belgian tax authorities. The Federal Public Service (SPF) has grown more alert to behaviours that suggest hidden income, speculation, or underreporting. Below are some of the most common reasons why your crypto activity may be selected for audit.
Unreported or Incomplete Crypto Declarations
Failing to declare your crypto income or capital gains is one of the quickest ways to catch the attention of the SPF. This includes forgetting to report wallet addresses, DeFi activity, airdrops, or trades made through lesser-known exchanges.
Incomplete records or vague entries in your tax return may trigger an inquiry. Belgian authorities are especially attentive to missing declarations when taxpayers convert crypto to fiat or receive rewards without including them as taxable income.
Frequent Crypto Trades or Speculative Activity
High-frequency crypto trading may move you out of the “prudent investor” category and into the speculative investor bracket, which comes with higher tax obligations. If you are actively buying and selling crypto to profit from short-term market changes, the SPF might view your actions as business-like. This kind of speculative behaviour often results in audits, especially if your tax return doesn’t align with your visible trading history on exchanges.
Use of Foreign Exchanges and Wallets
Transacting through offshore exchanges or storing crypto in foreign wallets can raise red flags, especially with the upcoming DAC8 directive. Belgian authorities now receive account-level data from international platforms like Coinbase or Binance.
If your reported figures do not match what SPF receives through these information-sharing agreements, you may be flagged for further review. Using DeFi wallets or non-custodial platforms without supporting records also adds to the risk.
Receiving Crypto as Income or Salary
If you’re earning crypto as compensation, whether from freelance work, mining, or staking, you must report it as taxable income. Many investors mistakenly believe that since crypto is decentralised, income in digital assets doesn’t count.
The SPF treats this like any other income and expects a fair market valuation at the time of receipt. Omission or underreporting of crypto-based income can easily trigger an audit, especially if linked to other irregularities in your tax file.
Mismatched Lifestyle vs. Reported Income
Large purchases funded by crypto, such as luxury vehicles, electronics, or property, can appear suspicious if they don’t match your reported income. The SPF uses lifestyle indicators to assess whether your declared earnings justify your spending habits.
If your bank deposits, real estate ownership, or other visible assets suggest you have more money than your tax return shows, they may initiate an audit to trace the source, often starting with your crypto records.
Read More: Crypto Tax In Belgium – The Ultimate Guide
How Long Can the SPF Audit Your Crypto Returns?
Even if your tax return has already been filed and accepted, it doesn’t mean you’re in the clear. The Belgian tax office reserves the right to reopen your case if they suspect inconsistencies or hidden earnings, especially in crypto. Depending on the situation, different timelines apply. Here’s how long the SPF can legally audit your crypto-related tax filings.
Standard Audit Period: 3 Years
For most taxpayers, the standard audit window is 3 years from the start of the tax year being assessed. For example, if your crypto activity took place in 2024, the SPF can audit you until 31 December 2027. This rule applies whether you’re reporting as an individual or a business.
This timeline ensures that authorities have ample opportunity to review your transactions and supporting documentation. It’s important to store all crypto-related records, such as wallet logs and exchange history, for at least this period, even if you think the return is straightforward.
No Filing or Late Filing: 4 Years
If you fail to file your tax return on time or miss it altogether, the SPF extends the audit period to 4 years. This extension gives the tax office more time to assess and investigate missing or delayed declarations, especially if crypto activity is suspected.
Many investors assume that minor delays won’t affect audit risk, but Belgian authorities consider late submissions a potential sign of tax evasion. To avoid scrutiny, always file your crypto-related returns promptly, even if you believe the gains are minimal or tax-free.
Suspected Tax Fraud: Up to 10 Years
When the SPF suspects that you have deliberately hidden income or acted with intent to deceive, the audit window expands drastically to 10 years. This includes cases where large crypto gains go unreported, or where transactions are structured to avoid taxation.
The tax office doesn’t need hard evidence to trigger this longer period, reasonable suspicion is enough. If your crypto activity looks unusually complex or inconsistent with your lifestyle, the SPF may assume intent and start a deep investigation covering up to a decade of past activity.
Foreign Data Triggers: Extra 2 Years
Belgium participates in several international agreements, including data-sharing treaties that allow tax authorities to receive information from foreign platforms. If the SPF receives crypto-related data from another country, such as trading reports from a US exchange, they can extend your audit period by 2 additional years.
Even if your return seems accurate, mismatches between what you report and what foreign sources disclose can trigger re-examination. This makes it essential to declare foreign exchange activity and hold supporting records in case you’re asked to justify the numbers.
Does Automated Detection Apply to Crypto Investors?
Yes, and it’s becoming more common. Belgium’s tax office uses automated systems to flag inconsistencies in personal and business filings, including those linked to crypto activity. If your declared income or gains don’t align with what exchanges, banks, or foreign tax offices report, the system can flag your file for review without any manual oversight.
For crypto investors, this means your trading volume, transaction history, and fiat conversions could all be analysed algorithmically. Sudden increases in wealth, high-frequency trades, or undeclared foreign assets might be picked up even if you’ve filed a return.
These triggers can lead to an automated request for information or a full-scale audit. Keeping your declarations clean and matching transaction records with submitted returns reduces the risk of being flagged by automated detection systems.
What Happens If You Are Selected for a Crypto Audit?
If the SPF selects you for a crypto-related audit, the process can range from a simple data request to a full review of your financial activity. The audit typically begins with a letter but can quickly escalate if the information provided is incomplete, inaccurate, or contradictory. Here’s what to expect during each stage of the audit process.
Initial Letter or Information Request from SPF
The audit usually starts with an official letter from the Belgian tax office asking for additional details about your crypto transactions. This request often includes a specific time frame and may target particular exchanges, wallets, or types of crypto income such as staking or mining.
You’ll be asked to respond within a given deadline. Ignoring or delaying your response may lead to penalties or assumptions made against your interest. That’s why it’s crucial to treat this first communication seriously and prepare your records right away.
Requirement to Provide Complete Transaction History
Once contacted, you will be expected to provide a full transaction history. This includes wallet-to-wallet transfers, crypto-to-fiat conversions, airdrops, and staking rewards. If you’ve used multiple wallets or exchanges, all accounts must be covered.
Failure to supply a complete record can result in penalties or higher estimated assessments. SPF may also compare your submitted data to information received from foreign tax authorities or blockchain analytics tools to ensure consistency across all sources.
Wallet Addresses, Exchange Logs, and Fiat Conversions
You’ll need to present documentation for every wallet and exchange you’ve used. This includes public wallet addresses, downloadable CSV logs from platforms like Binance or Kraken, and detailed summaries of every crypto-to-fiat transaction.
These documents help SPF verify your cost basis, selling price, and any associated fees. It’s especially important to show the exact date and value (in euros) of each conversion, as errors in these figures can lead to inflated tax bills.
Supporting Documentation for Valuation, Cost Basis, and Income
Auditors will require evidence of how you calculated your gains and income. This means showing where your euro values came from, what method (FIFO, LIFO, HIFO) you used for cost basis, and how you valued any staking or mining rewards at the time you received them.
You should also provide details of any deductions claimed, such as mining-related electricity costs, if you’re taxed as a professional. Every figure in your tax return should be backed by documentation, ideally generated by a trusted crypto tax tool.
Final Assessment and Possibility of Penalties
After reviewing your documents, SPF will issue a final tax assessment. If they find underreported income, late declarations, or intentional omissions, you may face penalties, back taxes, or fines. In serious cases, further investigations may follow.
To avoid these outcomes, accurate and consistent documentation is key. Keeping your crypto records audit-ready throughout the year, not just at tax time, can protect you from penalties and make the audit process far less stressful.
How To Respond To A Crypto Tax Audit in Belgium?
Facing a crypto tax audit in Belgium can be stressful, but how you respond plays a big role in the outcome. The SPF expects transparency, timeliness, and full cooperation during the process. Here are four key steps to help you handle the audit effectively and avoid unnecessary penalties.
Review the Audit Request Carefully
Start by reading the audit letter from the SPF thoroughly. It will outline the time period under review and list the specific crypto details being requested, such as exchange histories, wallet addresses, or staking income. Note the response deadline and instructions carefully.
Missing documents or late replies can escalate the audit. Before submitting anything, double-check that you understand what’s required. If you’re unclear about a section of the letter, don’t guess, connect with a professional.
Use A Crypto Tax Software To Organise Your Crypto Transactions
Manually collecting all your crypto trades, conversions, and rewards can be time-consuming and error-prone. Using crypto tax software like KoinX helps automate the process by importing transactions from multiple wallets and exchanges.
A tool like this ensures that your cost basis, holding periods, and capital gains are calculated correctly using accepted methods such as FIFO or HIFO. Clean and well-organised reports not only save time but also build credibility with the tax authorities during an audit.
Submit Your Crypto Records Without Any Discrepancies
Once you’ve gathered the required information, ensure all your records match what you reported in your tax return. Discrepancies, like mismatched euro values, missing trades, or inaccurate timestamps, can raise further questions and slow down the audit.
Submit clear, chronological transaction logs along with supporting documentation, such as screenshots or exchange statements. The more organised and complete your submission, the faster and smoother the audit resolution will be.
Contact A Tax Professional If You Are Confused
If you’re unsure about how to calculate your capital gains, whether your staking rewards count as income, or how to respond to complex SPF questions, it’s best to consult a qualified tax professional.
An experienced advisor can help you interpret the audit request, represent you in communications with the tax office, and reduce the risk of costly mistakes. Their guidance can be especially valuable if the audit involves large amounts or multiple years of crypto activity.
How Can KoinX Help You Stay Audit-Ready in Belgium?
We know that when you trade in cryptocurrency, you tend to use different wallets, exchanges and blockchains. Keeping an organised record and accurate reports of all your transactions is essential for filing your crypto taxes. If not, you may worry about a crypto tax audit in Belgium. However, KoinX simplifies the entire process by automating tracking, calculations, and reporting, so you’re always one step ahead if the SPF comes knocking. Here’s how it can help:
Integrates with 800+ Wallets and Exchanges
KoinX connects seamlessly with more than 800 wallets, exchanges, and blockchains, including both centralised and decentralised platforms. Whether you’re trading on Binance, using MetaMask, or staking on a DeFi platform, KoinX pulls all your data into one central dashboard. This ensures no transaction is missed or left undeclared.
Tracks Income and Capital Gains Automatically
Whether you’re earning through mining, staking, or short-term trading, KoinX calculates all your gains and income with complete accuracy. It applies the right classification based on your activity, capital gains, income tax, or speculative income, and provides summaries you can trust.
Applies Belgian-Compliant Cost Basis Methods
KoinX supports cost basis methods like FIFO, HIFO, and AVCO, which are all accepted by Belgian tax authorities. You can choose the one that aligns with your strategy and automatically apply it across your transaction history. This gives you full control and ensures you’re audit-compliant.
Generates Ready-to-File Tax Reports for SPF
Once your data is synced and calculated, KoinX generates detailed tax reports formatted for Belgian requirements. These include summaries of income, capital gains, and deductions, all of which can be directly shared with your accountant or uploaded to the MyMinfin portal for filing.
Supports Audit Logs with Verified Data Records
If the SPF asks for supporting documents, KoinX gives you timestamped records, cost basis details, and valuations in euros for every transaction. This makes it easy to justify the numbers in your tax return and reduces the risk of audit penalties due to missing information.
Are you ready to simplify your crypto tax compliance? Sign up for KoinX today and stay audit-ready throughout the year with real-time tracking and automated tax reports tailored for Belgium.
Conclusion
Crypto audits in Belgium are no longer rare. With enhanced data access and automated tracking, the SPF can easily spot inconsistencies in your tax filings, especially if you’re actively trading or earning crypto income. That’s why staying prepared is no longer optional.
Tools like KoinX give you the clarity and structure needed to manage your crypto portfolio and tax records year-round. From tracking trades to generating audit-ready reports, KoinX helps you respond with confidence and stay compliant with Belgian tax law. Join KoinX today to remove the guesswork and prepare for any audit, before the tax office even reaches out.
Frequently Asked Questions
How Can I Check If I Am at Risk of a Crypto Audit in Belgium?
You can’t always predict an audit, but high trading volumes, foreign wallets, and large undeclared gains increase your risk. If your lifestyle, income, and crypto activity don’t align, the SPF may investigate. Always ensure your tax filings match your actual crypto records. Keeping detailed transaction logs and using audit-friendly software can help you minimise exposure to potential red flags.
Do I Need to Report Crypto Held in Cold Wallets?
Yes, crypto stored in cold wallets must be reported if it’s been used in trades, converted to fiat, or earned as income. Even though it’s offline, its acquisition and disposal still create taxable events. You should maintain proper records of wallet addresses, asset values at acquisition, and transaction history to support your tax filings in case of an SPF audit.
Are Stablecoin Transactions Also Audited in Belgium?
Stablecoins are treated the same as other cryptocurrencies for tax purposes. Whether you’re converting to or from stablecoins like USDT or USDC, these are taxable events that may be audited. Failing to report such conversions can raise concerns. It’s important to track and declare all stablecoin-related activity, especially if it results in profit, income, or a noticeable change in portfolio value.
How Detailed Should My Crypto Records Be?
Your crypto records should include every trade, wallet address, date, cost basis, transaction value in euros, and fees. You must also store exchange statements, screenshots, and blockchain logs, especially if transactions occur across multiple platforms. These records help justify your numbers during an SPF audit and must be kept for up to 10 years, depending on the nature of your filing.
