Crypto Exchange Tax Report Wrong: How to Correct It Before the Tax Office Does

If your crypto exchange's tax report is wrong, you have to correct it yourself. The German tax office treats that document as an aid and not as proof. You alone are responsible for the figures in your tax return, even when the exchange made the mistake.

That sounds harsh, and it has been clearly settled since the Federal Ministry of Finance's circular of March 6, 2025. Anyone buying or selling through a central trading platform run by a foreign operator has to download and retain the transaction overviews provided there, regularly and in full. Missing records and data losses expressly count against you. This piece shows how to spot a faulty report, how to correct it, and which deadline applies once the return is already with the tax office.

Why an Exchange Tax Report Is Almost Never Complete

A trading platform only knows what happened in its own accounts. The moment you move Bitcoin from an exchange to a wallet of your own, its field of view ends. The platform sees a withdrawal and does not know whether you sold, gave the coins away or merely relocated them. If the same coins arrive on another platform months later, that second platform sees an inflow with no acquisition cost.

This is exactly where the typical wrong amounts come from. One exchange assumes a sale where none took place. Another sets the acquisition cost to zero because it lacks the prior history. Together the two can report a gain that never existed, and in the other direction make a real gain disappear.

On top of that, many reports are built for a different legal system. Providers with an international client base often calculate under rules that do not apply in Germany. Our guide to exporting the tax records from your crypto exchange describes how to get hold of the raw data you need to check any of this.

The Five Most Common Errors in a Crypto Tax Report

In practice the same patterns repeat. Check these five points first.

1. Transfers between your own addresses are listed as sales. Moving coins to your own wallet is no disposal and triggers no tax. It still often turns up in the report as an outflow.
2. Acquisition costs are missing and set to zero. The full sale proceeds then become the gain. That is the most expensive single error of all.
3. The holding period restarts although it was still running. After a transfer some reports set the acquisition date to the day of arrival. Tax-free long-held stock then appears to be a taxable new purchase.
4. A swap into a stablecoin is missing as a transaction. Swapping one coin for another is a disposal even when no euro moves. Reports that only count euro movements overlook it.
5. Fees and charges are allocated incorrectly. Trading fees belong to acquisition or disposal costs. If they are missing, you pay tax on an inflated gain.

Then come the special cases that defeat almost every piece of automation: income from staking and lending, airdrops, hard forks, payments made in crypto assets and everything that ran through a decentralised protocol. These transactions happen outside the exchange, and that is why they do not appear in its report either.

Who Is Liable When the Report Is Wrong: the Tax Office Comes to You

Under German law the responsibility sits with you, and from two directions. Section 90 of the Fiscal Code obliges you to cooperate, and to a heightened degree where facts lie abroad. The Federal Ministry of Finance circular of March 6, 2025, which replaces the older version of May 10, 2022, turns that into a concrete duty: transaction overviews from the platform are to be downloaded and retained regularly and in full.

The practical core of that sentence is often skipped. An exchange can block your access, cease operations or trim its data holdings after a year-end. Anyone who has saved nothing by then stands without proof, and the loss falls on you rather than on the provider. Anyone using tax software additionally needs process documentation under the principles of proper bookkeeping, meaning a traceable description of which data fed into the result and how.

How to Find the Error: the Reconciliation in Four Steps

The reconciliation is manual work, but it is finite. Four steps are enough for a reliable result.

1. Check that the accounts are complete. List every platform, every wallet and every protocol that was active in the tax year. A single forgotten account makes every further calculation worthless.
2. Reconcile the balances at the year-end. The prior year's closing balance plus all inflows minus all outflows has to equal the closing balance of the tax year. If the sum does not work out, a movement is missing.
3. Pair up every transfer. Every withdrawal from platform A must have a matching inflow on wallet or platform B, with a matching amount and a matching timestamp. Unpaired transfers are the main source of invented gains.
4. Recalculate the ten largest transactions individually. The error almost never sits in the mass of small amounts. Check the price, amount, fee and date of the largest items by hand against the raw data.

For the first three steps a tool that merges several accounts and pairs transfers automatically is worth having. Our comparison of crypto tax software and portfolio trackers shows which programs manage this for the German legal framework and where their limits lie. The result still remains your statement and not the program's.

Which Figure Applies in Case of Doubt: Acquisition Cost, Holding Period and Exemption Limit

Before you correct anything you have to know what the right result would have been. For private investors the private disposal transaction under section 23 of the Income Tax Act applies. If you sell within one year of acquisition, the gain is taxable. After a year has passed it stays tax-free. The gain is the disposal proceeds less the acquisition cost and the directly related costs.

Two figures decide almost every correction. First, the exemption limit of 1,000 euros per calendar year for all private disposal transactions combined: if it is exceeded, the entire gain is taxable and not merely the excess. Second, the order in which holdings count as used up. The customary approach is to look at each wallet or account on the principle that the units acquired first are disposed of first. If you switch that method between two years, you create exactly the kind of break that shows up in the report later.

When Data Is Gone for Good: Estimation Under Section 162 of the Fiscal Code

Sometimes data is irretrievably lost, for instance because an exchange was wound up. The tax office may then estimate the tax base under section 162 of the Fiscal Code. An estimate is no blank cheque for the authorities, but it rarely turns out in your favour, and the burden of proving a lower figure then falls on you.

It is therefore better to estimate yourself and to disclose the estimate. Document which data is missing, why it is missing and how you derived the figure you applied, for example from the daily price at a verifiable source for the transaction time evidenced on the blockchain. A reasoned estimate of your own, named in your covering letter, is something entirely different from a figure quietly plugged in.

How Long You Have to Keep the Documents

There is no general retention period for private investors of the kind that applies to businesses. What matters in practice is the assessment period. For income tax it is usually four years, five in cases of reckless tax reduction and ten in cases of tax evasion. As long as it runs, the tax office can take up the case, and for that long you need the records.

Two groups face an explicit duty. Anyone trading or mining commercially falls under the retention duties for accounts and records. And anyone with surplus income of more than 500,000 euros in a calendar year has to keep the underlying records for six years under section 147a of the Fiscal Code. For everybody else the plain rule of thumb applies: download each platform's annual data at the start of the year and file it twice. The effort involved runs to minutes; the effort of reconstructing it three years later runs to days.

Report Corrected, Return Already Filed: Section 153 of the Fiscal Code

If you only notice the error after the tax return has gone out, a separate provision applies. Under section 153 of the Fiscal Code you have to notify and put right without delay once you subsequently realise that a filed return was incorrect or incomplete and that this could lead to an understatement of tax. That applies for as long as the assessment period is still running.

Without delay means without culpable hesitation, so not at the next year-end. In practice you send a short letter to your tax office naming the transaction, stating the corrected figures and enclosing the new documents. Filing the entire return again is not necessary for this. What matters is that the letter makes clear which item changes, how and why.

This correction is the cheap route. Anyone who lets a recognised error lie risks an oversight turning into an accusation after the fact.

The Assessment Has Arrived and It Is Wrong: Appeal Within One Month

Once a tax assessment based on wrong crypto figures exists, the clock counts. Under section 355 of the Fiscal Code the appeal has to be lodged within one month of notification of the assessment. With postal delivery, notification is usually the third day after posting, and not the day you opened the envelope.

An appeal initially needs only form and deadline; you can supply the reasoning later. You should know two points. First, an appeal does not suspend the obligation to pay: anyone who does not want to pay has to apply separately for a stay of enforcement. Second, in appeal proceedings the case is reviewed again in full, including to your detriment. Anyone wanting to correct only a small item should therefore have checked the remaining entries themselves beforehand.

When Income Was Missing Altogether

There is a legal difference between a miscalculated report and an entire category of income left undeclared. Where transactions were not stated at all and that was more than an oversight, the territory of tax evasion comes into play. Section 371 of the Fiscal Code provides for the voluntary disclosure with exemption from penalty, but only with a complete subsequent declaration of all unexpired periods for a type of tax, and only as long as no bar has arisen. An audit that has already been announced is such a bar.

This is the one point in this text where you should not carry on alone. An incomplete voluntary disclosure can fail in its effect and make the position worse. Anyone uncertain here should go to a tax adviser or a lawyer specialising in tax law before writing to the tax office at all.

What the New Reporting Duty Changes From the 2026 Reporting Year

Until recently a faulty report was mainly your own problem. That is changing right now. With the implementation of the European directive DAC8, crypto service providers report their clients' accounts and transactions to the tax authorities, for the first time for the 2026 reporting year. The authorities exchange that data within the EU.

For you this means your figures will in future be held against a second source. If your return diverges from the report, grounds for an audit arise, even where your figure is the correct one. That makes your own documentation all the more important, so you can explain a divergence, for instance a transfer that the reporting platform saw as an outflow and that in truth landed in your own wallet.

A second point concerns the choice of platform. Providers authorised within the European framework generally deliver structured annual data and are set up for the reporting anyway. Anyone trading with a provider outside the European framework has to secure the entire data basis themselves.

Correcting Your Tax Report: What to Take Away

1. Treat the report as a draft and not as a result. Run the four-step reconciliation before any figure moves into your return. Which platforms deliver usable annual data can be seen in our crypto exchange comparison.
2. Save the raw data yourself every year. A platform failure excuses nothing; under the Federal Ministry of Finance circular the data loss counts against you. A tool from our comparison of tax software and portfolio trackers takes the merging off your hands, but not the retention.
3. Act within the deadline. Error spotted before the assessment: correction under section 153 of the Fiscal Code, without delay. Error in the assessment: appeal within one month. And for the 2026 reporting year a platform with European authorisation simplifies the data position, as our comparison of regulated crypto exchanges shows.

(As of September 27, 2026. This article is not investment advice. Prices and fee structures change; check the terms with the provider before you buy.)

This text is no substitute for tax advice in an individual case. Primary sources: the Federal Ministry of Finance circular of March 6, 2025 on crypto assets and section 153 of the Fiscal Code.