Tax office & cash: Federal Fiscal Court stops estimating income
- Patricia Lederer
- 3 days ago
- 3 min read
Federal Fiscal Court publishes ruling against the estimation of income during tax audits
Frankfurt am Main
April 4, 2026
The tax office estimates income – often without a clear basis. Especially with cash, the tax office is quick to assume something is amiss. So, an estimate is made.
A further ruling by the Federal Fiscal Court (BFH) now sets clear limits to this practice. The Federal Fiscal Court published the decision on March 19, 2026.
The tax office's estimate of income
A self-employed woman failed to file a tax return for a year. The tax office reacted immediately: it estimated her income. The method was simple – and problematic: four clients per day, €70 per client. This led the tax office to estimate over €40,000 in annual income. The result: a substantial tax bill.
The woman is fighting back.
The crucial question is: Where do these figures come from?
The tax office cites "empirical data" from the tax investigation unit. The tax court also adopts these figures.
But nobody reveals:
from which cases these values originate
whether the businesses are comparable
how the figures were determined
The person affected faces a clear problem: she is supposed to defend herself against an estimate – without knowing the basis for it.
Federal Fiscal Court ruling: Tax office must disclose data for estimation purposes
The Federal Fiscal Court intervenes. It clarifies: The tax office is allowed to make estimates. However, the estimate must be comprehensible. The basis for it must be disclosed.
If the tax office or court works with comparative values, they must specify them precisely.
Those affected must be able to check whether the figures are even correct.
If this does not happen, it violates their right to be heard.
Why the verdict is so important
The ruling addresses a key issue in tax law:
The tax office often uses internal data for its estimates. This data often remains hidden. The Federal Fiscal Court is now putting a stop to this. It makes clear:
Estimates must not be a black box.
Cash and the tax office: a typical area of conflict
Whenever cash is involved, the tax office becomes particularly strict. Typical sectors include: gastronomy, services, crafts, and retail. In these cases, the tax office is quick to assume incomplete income. The result is estimated tax assessments – often significantly inflated.
Challenging the estimate: this is what matters
If the tax office makes an estimate, you need to check two things:
First: Is it even permissible to make estimates?
Secondly: Is the amount of the estimate justified?
Height often provides points of attack.
The new ruling significantly strengthens the position of affected business owners and self-employed individuals. Without verifiable data, an estimate simply cannot stand up to scrutiny.
An appeal will decide what happens to your money.
Many people accept an estimated tax assessment – and that's precisely where the problem lies. Without an objection, the tax assessment remains valid. Those affected only have one month to react. By filing an objection, you force the tax office to review the estimate. And this is exactly where many assessments can be successfully corrected.
Conclusion
The highest tax court sets clear limits on the tax office's estimation of income:
The tax office is allowed to make estimates – but not in secret.
Comparative data must be available. Estimates must be verifiable.
For affected entrepreneurs and self-employed individuals, this means: They can defend themselves against assessments – and should do so.
TaxPro – the first address against tax office estimates
The Federal Fiscal Court is thus continuing its recent case law against the tax office's estimates.
Attorney Patricia Lederer, tax specialist at TaxPro GmbH , has played a key role in this development of case law and has won landmark rulings against the estimates.
➡️ The tax office must take into account the specific characteristics of the business when making its estimate. The estimated income must actually be achievable by the specific business. The estimate must be plausible and proportionate.
➡️ An estimate should not be based on the so-called "bible," the collection of guidelines from the Federal Ministry of Finance. The data contained therein are unsuitable as comparative parameters.
➡️ If the estimate is based on comparative values from other cases, the tax office must disclose these comparative values. According to the now-published ruling, the same applies to the tax court, which, in the first instance, relies on comparative values from other cases.
The now-published verdict shows:
Businesses need a clear defense against unlawful valuations.
Without professional help, companies risk being crushed between inflated fantasy figures and unrealistic recalculations .
TaxPro is the first address when it comes to dismantling tax office estimates and protecting clients from ruinous consequences.
Attorney Lederer reveals more in an interview with Handelsblatt:
