Multinationals in Portugal Face a Wednesday Deadline for Their First Global Minimum Tax Return
Groups with revenue of 750 million euros or more must file the Modelo 63 information return by 30 September, three months later than first planned. It lets the tax office check that they pay at least 15 percent.
Large multinational groups operating in Portugal have until the end of Wednesday, 30 September, to file their first return under the global minimum tax, the regime that aims to ensure big companies pay at least 15 percent tax on their profits in every country where they operate. The original deadline was 30 June; the government pushed it back by three months in the summer, ECO reported.
What the return is
The regime, known in Portugal as the Regime do Imposto Mínimo Global (RIMG), was approved by Law n.º 41/2024 of 8 November, which brought the EU's Pillar Two directive (Directive 2022/2523) into Portuguese law. The directive puts into effect, across the European Union, the global agreement reached at the OECD and G20 on a minimum level of corporate taxation.
It applies to multinational groups and large domestic groups with annual consolidated revenue of at least 750 million euros in at least two of the four previous years. Where a group's effective tax rate in a country falls below 15 percent, a top-up tax is due to bring it up to the minimum, and each country is responsible for making sure the group's entities on its territory are taxed at that level.
The return due now is the information return on the top-up tax, the Modelo 63, known internationally as the GloBE Information Return. The government approved the form in June by ministerial order published in the Diário da República. It gives the Tax and Customs Authority (AT) the data needed to work out whether a group owes the top-up tax and how much. A separate registration return, the Modelo 62, was created in 2025 by Portaria n.º 290/2025/1.
Groups do not always have to file locally. Under the rules, the Portuguese entities are exempt if the return has been filed by the group's ultimate parent, or by a designated filing entity, in a country that has a qualifying agreement with Portugal for exchanging the information.
Why the deadline moved
According to a decision by the Secretary of State for Tax Affairs, Cláudia Reis Duarte, cited by ECO, the extension was granted for three reasons: the need for coordinated action within multinational and large national groups, the aim of improving the quality of the information and reducing filing errors, and the fact that the OECD allowed countries facing difficulties to use domestic law to waive penalties or defer local filing. It covers groups whose fiscal year ended between 31 December 2024 and 31 March 2025, and allows them to file by 30 September without surcharges or penalties.
Who it affects
The regime reaches only very large groups, so the vast majority of companies in Portugal, including small firms and the self-employed, are not covered and have nothing to file. It does matter for the Portuguese subsidiaries of foreign multinationals and for the handful of Portuguese groups above the threshold. Portugal's tax incentives can bring a company's effective rate below 15 percent, and the minimum tax is designed to claw back the difference.
The deadline falls as the government prepares its 2027 budget, which it has said will include a further cut in the standard corporate income tax (IRC) rate. The minimum tax sets a floor under that competition for the largest groups: however low the headline rate, a group above the threshold should end up paying at least 15 percent somewhere.
Companies that miss the deadline face the penalties set out in the regime. The AT publishes the legislation, forms and guidance in the Pillar 2 section of the Portal das Finanças, under the large taxpayers area.
