Tax Authority Asks About Crypto: What to Do?

An official letter from the tax authority asking about your crypto transactions. That's unusual at first. But also no reason to panic. Let's look at what this means and how to handle it.

TX-Partner is the independent partner for crypto accounting: the data basis that tax advisors and the tax authority work from. And that is exactly what an inquiry like this is about. At its core it is a data request today, not a tax question. The tax authority wants the complete, verifiable history of your crypto activity, and every calculation built on top of it rests on that data basis.

01 What Does a Tax Authority Information Request Mean?

A supplementary request (in Austria) or information request (in Germany) is a normal inquiry. The tax authority wants more information about a specific matter. In your case: about your crypto activities.

Important to understand: This is not an accusation and not a criminal proceeding. It's an audit. The tax authority has received data (for example through DAC8 reports) and wants to compare it with your statements. Or they simply lack information.

02 Why Is the Tax Authority Asking About Your Crypto?

Crypto inquiries from the tax authority typically have specific triggers. Here are the most common ones:

None of these reasons is inherently problematic. It's about establishing transparency. You can do that.

03 DAC8: The Facts

DAC8 (Directive on Administrative Cooperation) is the EU directive that extends automatic information exchange to crypto assets. Crypto service providers have been collecting the data since January 1, 2026; the first reports to tax authorities follow in 2027 (Germany by July 31, 2027, EU-wide by September 30, 2027). What gets reported are aggregated gross values per asset and year, plus identification and wallet data. The tax authority reconciles these reports with your tax return, and a discrepancy is the most common trigger of an inquiry.

The full DAC8 mechanics, what exactly gets reported, and where the reporting systematically leaves gaps, live in the dedicated article: DAC8 and Crypto Accounting.

04 Collective Information Requests: The Bitcoin.de Case

Besides DAC8, there's another reason for tax authority inquiries: collective information requests. The best-known example is Bitcoin.de.

The initiator was the State Office for Combating Financial Crime NRW (LBF NRW). The collected data is distributed nationwide to the responsible tax authorities. This means: If you live in Bavaria but data was collected in NRW, you'll get mail from the Bavarian tax authority.

Source: Tax Administration NRW

05 Austria vs. Germany: The Differences

The terms and legal bases differ between countries. Here's an overview:

The processes are similar, but the legal details differ. For specific handling, coordination with a tax advisor who knows the respective country's law is always recommended. For the full tax framework for Austria, see the Crypto Tax Austria 2026 guide. For Germany (holding period, FIFO, Anlage SO), see the Crypto Tax Germany 2026 guide.

Sources: Austrian Federal Ministry of Finance, German Tax Code

06 What happens if you don't respond?

Ignoring is not a strategy. Here are the possible consequences:

Sources: German Tax Code (§162, §370 AO), Austrian Federal Ministry of Finance

Voluntary Disclosure as an Option

If you realize that mistakes were made in the past, voluntary disclosure can be an option. Important: Voluntary disclosure must occur in time - that is, before the tax authority becomes aware of the discrepancies on its own. The inquiry itself may have already passed this point.

What a complete voluntary disclosure requires, what the most common data gaps are, and why 2026 is the decisive window: Crypto Voluntary Disclosure 2026: What You Need to Know Now.

07 What is typically requested?

The requirements are stated in the letter, and they are more concrete than many expect. The six points that TX-Partner sees in real information requests are, at their core, data requests. By now they reach small investors too, not just high-volume traders. The same logic applies to every point: only once the data basis is complete and verifiable can the question be answered cleanly.

1. Which trading platforms were used?

The tax authority wants the complete list of all exchanges and brokers used. The data basis for it is a source overview of every account ever active, including the ones shut down long ago and the very first exchange almost nobody still thinks about. You establish it by listing every platform and pulling a complete CSV export per platform, not just the current year.

2. In which wallets were the crypto assets held?

The question is where the coins sat: on the exchange (custodial) or in your own custody (self-custody), and there in hot or cold wallets. The data basis is a list of all wallet addresses with their respective chain, because the same address has to be recorded separately per chain (Ethereum, Polygon, Arbitrum, Solana and so on). You establish it by documenting every address and reconciling it against the imported data via the block explorer.

3. What amount of income was generated?

Here the tax authority asks for a figure. But this figure is not a starting point, it is a result: it rests on the complete, correctly classified transaction history. The tax assessment of this amount belongs with tax advice; the solid data basis underneath it is documentation work. If a purchase transaction is missing, the tax tool calculates with a cost basis of 0 euros and reports an inflated gain that nobody actually realized.

4. All records relating to the trading

This means all documentation around the trades: annual statements from the exchanges, bank statements with crypto references, deposit and withdrawal receipts. The data basis is your complete receipt archive per platform. You establish it by exporting missing statements through the account or, for closed exchanges, requesting them via a GDPR data request.

5. All electronic data on holdings and trades

The tax authority requests the raw data itself: the machine-readable transaction histories from which every event can be traced. The data basis is the complete CSV and API exports plus the on-chain history. You establish it by importing all sources cleanly into a tax tool and classifying the on-chain events correctly, so that the electronic data is internally consistent.

6. The exact calculation of the gains and losses realized

This is the point closest to tax, and precisely for that reason the point where the roles separate. The calculation itself is run by the tax tool, the tax assessment is handled by tax advice. But both stand and fall with the data basis underneath: only if every disposed position is linked to its acquisition without gaps does the calculation produce a verifiable result. Establishing exactly this gapless linkage across all wallets and exchanges is the actual work.

The good thing about this: The requirements are clear. You know exactly what you should deliver. The only question is: Do you have it?

08 The tax authority can recalculate itself

Why does the tax authority want the raw data specifically, and not just a finished figure? Because it can recalculate itself. From over 500 cases, TX-Partner sees the same pattern: the authority often runs the data it holds through the same crypto tax tools you use.

From that follows a simple mechanic. If your own data is incomplete or unpaired, the tax authority's tool can produce a different result than yours. An unpaired deposit, for example, lands in the report with a cost basis of 0 euros and drives the reported gain upward. Exactly such a discrepancy can trigger the inquiry in the first place. The lever therefore lies not in the tax assessment, but in the completeness of your data, and that is exactly where TX-Partner starts.

09 Case variant: holding period per disposed position

In a more recent variant, the inquiry goes one step deeper. The tax authority asks for suitable evidence from which the holding period of the individual disposed currencies is also apparent. What is required is no longer just the transaction list, but a lot-level transaction log: for every position sold, the acquisition and the disposal date.

The background is the one-year holding period for private crypto sales (§ 23 EStG in Germany; in Austria mainly relevant for legacy holdings). Whether and how it applies in a specific case is assessed by tax advice. For the data layer, something else counts: a holding period can only be shown if the purchase and sale of each unit are linked without gaps, across all wallets and exchanges (FIFO allocation). If acquisition data is missing or transfers are unpaired, the holding period simply cannot be substantiated.

This inquiry too is therefore, at its core, not a question of assessment but a question of data quality, consistency, and traceability. Preparing exactly this lot-level history is the work TX-Partner does, ideally before the inquiry even arrives.

10 How to Respond to a Tax Authority Crypto Inquiry

A supplementary request is an information inquiry, not a criminal proceeding. You have time, and the path is clear. The essentials in three steps:

1. Check the deadline, stay calm. Typically 2 to 4 weeks. If the time isn't enough, you ask in writing for an extension, which is usually unproblematic.

2. Check the tax report for warnings. Open your Blockpit or CoinTracking report. If it shows "Short (Warning)", "Missing history", or negative balances, these gaps should be closed before submission, because they are exactly the leads the next follow-up latches onto.

3. Establish the data basis, then respond. Always in writing, never by phone. The tax assessment and the final submission are handled by tax advice; TX-Partner first brings the crypto accounting to an audit-ready state.

The complete step-by-step process, including the Austrian and German deadlines, is laid out in the guide: Respond to a supplementary request.

11 Documentation makes the difference

The inquiry itself is rarely the problem. The challenge arises when your tax report doesn't show what it should.

Submitting a report with negative balances or cost basis 0 EUR essentially hands the tax authority the next prompt for an inquiry. The result is a discussion about why the documentation shows gaps. The clean route is the other way around: correct the documentation before submission, so the report leaves no open flanks.

12 Preparation instead of reaction

The best time to get crypto accounting in order is before the letter arrives. The second-best is now. Ideally the documentation is already cleanly prepared, then the inquiry is a formality: export report, submit, done.

In practice, the inquiry often arrives at the exact moment it becomes clear that wallets are missing, DeFi isn't fully captured, the report shows warnings. That's where TX-Partner steps in: not as tax advisor, but at the data root. TX-Partner identifies the gaps, reconstructs missing transactions, classifies DeFi activity correctly, and brings the report to a state your tax advisor and the tax authority can work with.

If it's unclear whether your crypto accounting holds up against the inquiry, Robert or Johannes will look at it in the free Data Check and give an honest assessment of what you can prepare yourself and where professional rework makes the difference. 30 minutes, no commitment.