Portuguese IRS – Amended Tax Returns and Late Filings

Olhar Fiscal is a publication by Caiado Guerreiro, with the participation of partner Ana Castro Gonçalves and trainee lawyer Sara Godinho Barão, dedicated to clarifying issues related to Tax and Social Security Law. In this edition, amended IRS tax returns are analysed.
Articles 22/05/2026

When do I need to file an amended tax return?

If the taxpayer has used the automatic tax return option, they may still file an amended return within 30 days following the assessment, without any penalty, whenever they verify that the elements assessed by the Tax Authority differ from the factual reality.

An amended return may also be submitted in order to declare new income earned in previous years, regarding those respective years, to correct an updated final value used for IMT (Property Transfer Tax) purposes, or to adjust a disposal value, among other situations. As a general rule, an amended return should be filed whenever there is any change to the information previously provided.

In which cases is the deadline for filing IRS extended?

As is generally known, IRS assessments must, as a rule, be carried out by 30 June of the year following the one to which the income relates. An amended return must be submitted whenever a fact arises that alters the determination of the declared income, within 30 days following the occurrence of such fact.

With regard to foreign-source income for which the amount of the foreign tax credit for double taxation purposes has not yet been determined at source, the deadline for filing the return is extended until 31 December of the relevant year.

What if my original return, or amended return, is submitted after the deadline?

Where no extension of the deadline applies, or where one of the aforementioned extensions applies but is nevertheless disregarded, this may constitute a case of “failure or delay in filing returns”. Under the General Tax Infringements Regime, such infringement is punishable by a fine ranging, in principle, from €150 to €3,750.

Reduction, mitigation, and waiver of fines

A waiver of the fine may apply where, in the previous five years, the taxpayer has not been convicted by a final and binding decision in administrative offence proceedings or criminal proceedings relating to tax infringements, nor benefited from a waiver or reduction of fines, provided cumulatively that the infringement caused no damage to tax revenue and that the omission has been remedied. Such waiver must be requested after the regularisation has taken place, which must occur within the deadline granted for the defence.

The mitigation of the fine also depends on a request by the offender to that effect, provided that they acknowledge responsibility for the infringement and regularise their tax situation. In such cases, the limits of the fine for the aforementioned administrative offence are reduced to €75 and €1,875, respectively. Furthermore, where the infringement and the offender’s degree of fault are deemed particularly minor, the competent authority may issue only a formal warning.

The right to reduce the fines to 12.5% or 50% of the legal minimum amount depends on the prompt payment of the fine or the regularisation of the tax situation, which, in the present case, would correspond to €18.75 or €75.

With regard to what constitutes the proper regularisation of the taxpayer’s situation, this consists of fulfilling the tax obligations that gave rise to the infringement.

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The content of this information does not constitute any specific legal advice; the latter can only be given when faced with a specific case. Please contact us for any further clarification or information deemed necessary in what concerns the application of the law.

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Practice Areas

  • Tax Law

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