A landmark ruling by Greece’s Council of State has dealt a significant blow to extended tax investigations, declaring unconstitutional the 20-year limitation period for tax evasion and rejecting a transitional 10-year provision. The decision could affect thousands of older tax cases, although it does not automatically cancel outstanding debts or previously finalised assessments.

The ruling, numbered 1246/2026, establishes that the standard five-year limitation period must apply in cases where tax authorities relied solely on the extended deadlines to impose additional taxes or penalties.

The decision has particular implications for tax years between 2012 and 2017, potentially calling into question assessments issued long after the original five-year deadline had expired.

Greece’s Independent Authority for Public Revenue (AADE) is reportedly preparing to implement the ruling, requiring officials to distinguish between cases that have become time-barred and those where a separate legal provision allows investigations or assessments to continue.

Why the court rejected the longer deadlines

Under Greece’s former Tax Procedure Code, a 20-year limitation period applied specifically to cases classified as tax evasion. This was not the general deadline for all tax investigations but an exceptional provision intended to give authorities considerably more time to pursue suspected offences.

Subsequently, legislation introduced in 2019 established a transitional 10-year limitation period for the 2012 and 2013 accounting years and the 2014-2017 tax years.

However, the Council of State ruled that the 20-year period violated the constitutional principle of proportionality.

The court also found the transitional 10-year provision unconstitutional in the case before it because it retroactively extended the period during which the state could impose tax liabilities.

The decision strengthens the principle that tax authorities cannot simply classify an offence as tax evasion to justify issuing assessments many years after the standard deadline.

The €4,640 fine that triggered the ruling

The case at the centre of the ruling involved a honey-producing business that received a €4,640 penalty over an allegedly fictitious invoice relating to the 2013 accounting year.

The penalty was imposed in 2020, even though the standard five-year limitation period had expired on 31 December 2019.

The authorities had relied on the extended limitation period to justify the assessment.

The Council of State ultimately ruled that the longer deadlines could not sustain the penalty, providing an important precedent for other taxpayers facing similar assessments.

The dispute illustrates that the consequences extend beyond large-scale tax investigations involving substantial income tax or VAT liabilities. Smaller businesses and individual taxpayers may also be affected.

Which tax years could be affected?

The ruling has potentially significant implications for tax years from 2013 to 2017, particularly where penalties or additional taxes were imposed after the standard five-year deadline.

The following dates illustrate the normal limitation periods, assuming that no lawful extension, suspension or other exception applies.

For the 2013 accounting year, the five-year period expired on 31 December 2019, compared with the end of 2024 under the disputed 10-year provision. An assessment imposed in 2020 solely on the basis of the extended period could therefore be challenged.

For the 2014 tax year, the standard deadline expired on 31 December 2020, rather than 31 December 2025 under the longer period. A tax assessment notified in 2023 and justified exclusively by allegations of tax evasion may consequently be open to challenge.

For the 2015 tax year, the five-year deadline expired on 31 December 2021. The transitional 10-year period would otherwise have continued until 31 December 2026. Assessments issued in 2024 or 2026 cannot necessarily be upheld solely because the case was classified as tax evasion.

For the 2016 tax year, the ordinary limitation period ended on 31 December 2022, compared with the end of 2027 under the longer deadline. A penalty imposed in 2025 on the basis of the extended period could therefore face a legal challenge.

For the 2017 tax year, the standard deadline expired on 31 December 2023, whereas the disputed 10-year period would have extended to the end of 2028. Assessments issued in 2025 or 2026 may consequently be vulnerable if tax evasion was the only justification for exceeding the five-year limit.

The ruling may also have implications for certain cases involving the 2012 accounting year.

However, the precise limitation period depends on the relevant tax, filing requirements and any applicable statutory exceptions. The dates above should not be treated as automatically applying to every individual case.

What tax authorities must now examine

The ruling places greater emphasis on the legal basis of each individual assessment.

It is not sufficient for the tax authorities to demonstrate that an investigation began before the limitation period expired.

Officials must also establish whether the final assessment was issued and properly notified within the applicable deadline.

An audit order or preliminary assessment does not, by itself, replace the final tax assessment required under the law.

For older cases, AADE will therefore need to examine when the relevant period expired, whether the final assessment was completed in time and which legal provision was used to justify any extension.

Where the longer deadline was based exclusively on the classification of an offence as tax evasion, the assessment may no longer have a valid legal foundation.

Which exceptions remain in force?

Despite the decision, the five-year period is not an absolute deadline for every tax investigation.

Specific exceptions may still allow authorities additional time, provided the statutory requirements are satisfied.

For example, the submission of a tax return during the fifth year could, under certain conditions applicable to tax years between 2014 and 2017, extend the deadline by one year.

Cases involving genuinely new or supplementary evidence may also qualify for a longer limitation period.

However, tax authorities must demonstrate that such evidence satisfies the relevant legal criteria, including whether the information could reasonably have been obtained during the original limitation period.

Simply reassessing documents or information already available to the authorities is not necessarily sufficient to justify a longer investigation.

Separate rules may also apply where a taxpayer has failed to submit a required return.

These exceptions mean that individual cases must still be assessed on their merits, rather than being treated as automatically time-barred.

Does the ruling cancel outstanding tax debts?

The court’s decision does not amount to a general cancellation of outstanding tax debts.

Nor does it automatically invalidate assessments that have already become final or overturn binding judicial decisions.

The procedural stage of each case remains crucial.

Taxpayers whose disputes are still being considered by administrative authorities or the courts may have grounds to challenge assessments that relied exclusively on the unconstitutional extended limitation periods.

By contrast, an assessment that was lawfully completed within the original five-year deadline is not affected simply because the courts have now rejected the longer periods.

An important distinction also remains between the limitation period for imposing a tax liability and the separate rules governing the collection of a debt that has already been lawfully assessed.

The ruling therefore does not mean that every debt relating to tax years before 2018 disappears.

What changes for taxpayers and businesses?

The central change is that an allegation of tax evasion is no longer, in itself, sufficient to justify extending the state’s right to impose additional taxes or penalties beyond the ordinary five-year period in the cases covered by the ruling.

For taxpayers and businesses involved in older disputes, this creates a potentially important avenue for challenging assessments issued after the normal deadline.

For AADE, it means that cases previously considered valid under the 10-year or 20-year provisions will need to be assessed against the constitutional requirements established by the Council of State.

Any attempt to justify a later assessment must rest on a separate, legally valid basis.

The decision marks a significant development in Greek tax law, strengthening legal certainty over how long taxpayers may remain exposed to additional assessments for historic tax years.