AIMI in Portugal: When Property Owners Pay the Additional IMI

• AIMI applies to the sum of the VPT of urban residential properties and building land you hold on 1 January (CIMI arts. 135.º-A to 135.º-C). Commercial, industrial, services and «other» buildings are excluded.
• An individual or an undivided estate deducts €600,000. A married or de facto couple that opts for joint taxation deducts €1,200,000 (arts. 135.º-C and 135.º-D).
• For individuals the rate is 0.7% after the deduction, 1% on the part of the total VPT between €1 million and €2 million, and 1.5% above €2 million. The bands are measured before the deduction (art. 135.º-F).
• The AT assesses it in June and you pay in one payment in September (arts. 135.º-G and 135.º-H).
• AIMI paid on rented property is deductible from the IRS tax, up to a cap, not from the rental income (art. 135.º-I).

AIMI is a separate yearly tax on the combined VPT of your Portuguese residential properties and building land, held on 1 January. An individual deducts €600,000, or €1,200,000 for a couple that opts for joint taxation, so most owners owe nothing. If you do owe it, the AT assesses it in June and you pay in September, in one payment. Next: add up the VPT of every property you own or hold in usufruct, check whether an exclusion applies, then work it out with the bands below. It sits alongside the ordinary bill explained in our IMI guide.

What is AIMI, and is it the same as IMI?

AIMI is an additional annual property tax on the combined VPT of Portuguese residential buildings and building land within its scope. It is separate from ordinary municipal IMI and is not calculated from market prices or by multiplying your IMI bill. Commercial, industrial, services and other property classifications are excluded under Article 135-B; other statutory exclusions must also be checked.

Does AIMI apply only to a single home worth more than €600,000?

No. Add the relevant VPT across the owner's eligible properties. Individuals normally deduct €600,000, or a couple electing joint taxation €1.2 million, but companies have no such allowance. The allowance does not apply to the vacant-for-over-a-year, ruined or vacant-part cases specified in Article 135-C(4). A home's market value below or above €600,000 is not itself the test.

Who owes it, and on what

Art. 135.º-A CIMI makes owners, usufructuaries and holders of surface rights over urban buildings in Portugal liable, whether they are individuals or companies. An undivided estate represented by its head of estate is treated as a company, unless it identifies every heir and their shares (art. 135.º-E). Who is liable is decided by the property register on 1 January of the year the tax refers to, not by who owns the property when the bill arrives.

The tax is charged on the sum of the VPT of the urban buildings the person holds (art. 135.º-B). Two groups are outside it: buildings classified as commercial, industrial or for services, and as «other», and residential buildings let under the Programa de Apoio ao Arrendamento — since 1 September 2026, under its successor, the Regime Simplificado de Arrendamento Acessível (RSAA): Decreto-Lei 97/2026 (art. 14.º a)) reads every legal reference to the programme as a reference to the RSAA, and leases already under the programme keep their tax treatment (art. 15.º n.º 2). That leaves, in the AT's own words, urban residential buildings and land for construction. Art. 135.º-C n.º 3 also leaves out buildings that were exempt from IMI or not subject to it the year before, and some buildings held by condominiums and housing cooperatives.

VPT is the taxable patrimonial value entered in the property register. It is not the price you paid, a bank valuation or an estate agent's estimate, and it is often well below all three.

The calculation

Two different numbers matter, and mixing them up is the commonest mistake. The rate of 0.7% applies to the value after the deduction (art. 135.º-F n.º 1). But the 1% and 1.5% bands are defined on the total VPT before the deduction, the value that art. 135.º-C n.º 1 calls the taxable value (art. 135.º-F n.os 2 and 3). The AT's public pages give the bands without a worked example, so the examples here apply the statute's wording, and your notice, which itemises each building, is the check.

Estates get the same €600,000 deduction and 0.7% rate but not the higher bands, because arts. 135.º-F n.os 2 and 3 apply them only to individuals. Companies pay 0.4% with no deduction, and entities in a blacklisted low-tax jurisdiction pay 7.5% (n.os 1 and 5, not applicable to individuals). A company's buildings for the personal use of its owners, directors or their close family pay the individual bands instead (n.º 4). The €600,000 deduction does not apply to buildings left vacant for more than a year, ruins, or parts left vacant (art. 135.º-C n.º 4, which refers to art. 112.º n.º 3 a) and b)).

Married couples: the joint option

Spouses and de facto partners, in the sense of art. 14.º of the IRS Code, can opt for joint AIMI taxation (art. 135.º-D). Their VPT is added together, the deduction is doubled to €1,200,000, and the bracket thresholds double too. It is not automatic: the option declaration is made only on the Portal das Finanças between 1 April and 31 May, and it stays valid until you renounce it (n.º 6). The AT says a couple can opt even if only one of them owns property.

With the option there is one assessment, and both spouses are jointly liable for paying it (art. 135.º-G n.º 2). Without it, each spouse is assessed on the buildings the register shows in their name. Couples married in community of property who do not opt can file a joint declaration to say which buildings are each spouse's own and which are common (art. 135.º-D n.º 2). If the deadline passed, the AT's FAQ, answering a couple married in community of property, says they can still opt within 120 days of the end of the voluntary payment period.

When it is assessed and paid

The AT assesses AIMI each year in June from the register as it stood on 1 January (art. 135.º-G). It sends the payment document, itemised by building, share, VPT and tax, by the end of the month before payment (art. 135.º-H n.º 3). Payment is due in September in a single payment, not in instalments as with IMI. Late payment carries default interest (n.º 4). If an assessment is made outside June, you pay by the end of the month after you are notified.

Because the register on 1 January decides, a sale later in the year does not remove that year's AIMI and a purchase later in the year does not add to it. If you bought or inherited during the year, expect the effect from the next 1 January.

If you let the property

Art. 135.º-I lets you deduct AIMI from the IRS tax, not from the rental income. The deduction is capped at the part of the IRS tax that is proportionate to your net Category F income when it is aggregated, or at the tax obtained by applying the autonomous rate in other cases. It also applies to Category B income from letting or hospitality. Companies can instead opt to deduct AIMI from the corporate tax (art. 135.º-J). The landlord's side is in our guide to rental income tax.

Checklist

• List every urban residential building and plot for construction you own, hold in usufruct or hold by surface right, with its VPT from the property register.
• Remove buildings that are commercial, industrial, for services or «other», and those let under the Programa de Apoio ao Arrendamento or, since 1 September 2026, the RSAA.
• Decide, with numbers, whether a joint option helps, and file it between 1 April and 31 May if so.
• Read the payment document the AT sends by the end of August and check each building and share.
• Pay in September, and if you let the property, use the IRS deduction.