Portugal Tax Alert: CAAD Confirms Full Category B Treatment for Property Sales After Business Use

A significant ruling on Portuguese IRS treatment of property previously allocated to a business activity

A recent decision from the Portuguese tax arbitration court, CAAD, has clarified an important point in the taxation of real estate that was previously used in a business or professional activity.

In CAAD Case no. 1036/2025-T, decided on 11 May 2026, the arbitral tribunal held that Article 10(16) of the Portuguese Personal Income Tax Code (Código do IRS, or CIRS) must be interpreted as requiring the application of the Category B regime as a whole where a property is sold within three years after being transferred back from a business activity to the taxpayer’s private sphere.

The importance of this decision goes beyond the facts of the individual case. It provides a potentially valuable interpretation of how Portuguese tax law should apply to property previously used for activities such as short-term rental accommodation, tourism accommodation, self-employed business activities, or other professional activities carried out by an individual.

The legal issue: Category B or Category G?

Under Portuguese IRS rules, gains from the sale of private real estate are normally treated as Category G capital gains.

However, Article 10(16) CIRS contains a special rule for real estate that has previously been allocated to an individual taxpayer’s business or professional activity.

Broadly, where a property:

• was previously allocated to a business or professional activity;
• was subsequently transferred back to the taxpayer’s private assets; and
• is sold within three years following that transfer,

the gain is taxed according to the rules of Category B, the category applicable to business and professional income.

The central question in the CAAD case was what the phrase “taxed according to the rules of Category B” actually means.

Does it refer only to the way taxable income is calculated?

Or does it also include the applicable tax rates and the wider Category B taxation framework?

CAAD adopted the broader interpretation.

CAAD’s doctrine: the Category B reference is not limited to the tax base

The Portuguese Tax Authority had taken the position that Article 10(16) only required Category B rules to be used when calculating the taxable gain.

Under that interpretation, the taxable amount could be determined using Category B methodology, while the final tax would still be calculated under the rules normally associated with capital gains.

CAAD rejected that interpretation.

The tribunal considered Article 10(16) to be a special rule of substantive tax incidence. Its wording states that the relevant gains are to be taxed according to the rules of Category B. According to the tribunal, there is no wording in the legislation that limits that reference solely to the calculation of taxable income.

This distinction is critical.

The tribunal’s reasoning implies that when Article 10(16) applies, the Category B framework may govern not only:

• the calculation of taxable income,

but also:

• the liquidation mechanism;
• the applicable tax rate;
• and other rules directly connected with the taxation of Category B income.

The official summary of the decision is particularly clear: Article 10(16), as a special rule of real tax incidence, extends to the determination of Category B income and to the applicable liquidation and tax-rate regime.

Why the wording of Article 10(16) matters

A key element of the decision is the tribunal’s reliance on statutory interpretation.

The wording of Article 10(16) does not state that only the “rules for determining taxable income” apply.

Instead, it states that the gains are:

taxed according to the rules of Category B.

For CAAD, this wording is broad and unqualified.

The tribunal considered that the only express statutory condition is temporal: the property must be sold before three years have elapsed since its transfer from the business sphere back to the taxpayer’s private assets.

The Tax Authority’s narrower interpretation therefore introduced a limitation that the tribunal could not identify in the text of the legislation.

This is an important principle for tax practitioners: where the legislator uses a broad reference to a complete tax category, the administration cannot necessarily isolate one computational rule while disregarding other elements of that category unless the law expressly supports that distinction.

Article 10(16) as a special rule

The tribunal also treated Article 10(16) as a lex specialis, meaning a special legal rule that prevails over the more general rules governing real estate capital gains.

This is significant because it affects the classification of the gain itself.

The decision supports the view that a property sale covered by Article 10(16) should not be treated as a conventional Category G transaction with only selected Category B computational adjustments.

Instead, the special rule can displace the ordinary capital-gains treatment and bring the transaction within the broader Category B taxation framework.

This interpretation is especially relevant for taxpayers who previously carried out business activities involving their property.

Relevance for non-resident taxpayers

The decision may be particularly important for non-residents disposing of Portuguese real estate previously allocated to a business activity.

In the case before CAAD, the difference between the Tax Authority’s interpretation and the taxpayer’s interpretation had a substantial financial effect because the relevant Category B rate applicable to the non-resident taxpayer was materially lower than the effective rate resulting from the Tax Authority’s approach.

The broader principle is more important than the individual numbers.

Where Article 10(16) applies, advisers should not automatically assume that the normal Category G rate mechanism remains applicable.

The correct analysis should instead consider:

1. whether Article 10(16) is triggered;
2. what Category B regime applies to the taxpayer;
3. whether the taxpayer is resident or non-resident;
4. whether a specific Category B rate applies;
5. and how the property was previously taxed while allocated to the activity.

Property used for short-term rental activities

This decision may have particular relevance for owners who previously operated Portuguese property through:

• Alojamento Local;
• furnished tourist accommodation;
• self-employed tourism activities;
• individual rental or hospitality businesses;
• or another Category B business activity.

A common scenario is:

1. the taxpayer allocates the property to a business activity;
2. later ceases the business or removes the property from the activity;
3. transfers the property back to the private sphere;
4. and subsequently sells the property.

Where the sale takes place within the statutory three-year period, Article 10(16) may become decisive.

The tax result can therefore differ significantly from the result that would apply to an ordinary private property sale.

Why the three-year period is critical

Article 10(16) only applies where the disposal occurs before three years have elapsed following the transfer of the property back to the taxpayer’s private assets.

This means that the chronology of the property must be carefully documented.

Taxpayers and advisers should establish:

• the date on which the property was originally allocated to the activity;
• the date on which it ceased to be allocated to the activity;
• the effective date of transfer back to the private sphere;
• the date of cessation of the business activity, where relevant;
• and the date of sale.

A difference of only a few months may materially change the applicable tax regime.

The decision also reinforces the importance of legal classification

One of the broader lessons from the ruling is that Portuguese tax calculations cannot be separated from the legal classification of the income.

The correct question is not merely:

“How should the capital gain be calculated?”

The prior question is:

“Which category of income legally governs this transaction?”

Once a transaction falls under the special rule in Article 10(16), that classification may determine the tax base, the applicable rate and the overall liquidation methodology.

This is why using generic Portuguese capital gains calculators can be particularly risky in cases involving property previously used in a business.

Does the CAAD decision bind the Portuguese Tax Authority generally?

Taxpayers should nevertheless exercise caution.

A CAAD arbitration decision resolves the dispute between the parties to that case. It does not operate in the same way as legislation or a generally binding Supreme Administrative Court precedent.

Accordingly, the decision should not be interpreted as meaning that the Portuguese Tax Authority will automatically apply this treatment in every future assessment.

It does, however, provide a strong and recent judicial interpretation of Article 10(16), supported by a three-member arbitral tribunal, and should be carefully considered in similar cases. CAAD’s official jurisprudence database confirms that the case concerned precisely the application of Article 10(16) to gains on property previously allocated to a business or professional activity.

Practical tax planning implications

For taxpayers considering the sale of a Portuguese property previously used in a Category B activity, the timing of the sale may have a significant tax impact.

Before proceeding, it is advisable to review:

• whether the property was formally allocated to a Category B activity;
• whether and when it was transferred back to the private sphere;
• whether the three-year Article 10(16) period is still running;
• the taxpayer’s residence status at the time of sale;
• the Category B regime applicable to the taxpayer;
• acquisition and improvement costs;
• and whether previous IRS returns correctly reflected the business allocation and subsequent transfer.

The resulting Portuguese tax liability can vary materially depending on these factors.

Key takeaway

CAAD Decision no. 1036/2025-T supports an important principle:

Where Article 10(16) CIRS applies, a gain from the sale of real estate previously allocated to a business or professional activity should be taxed under the Category B regime as a whole, including the applicable tax-rate framework, rather than using Category B rules solely to calculate the taxable gain.

For property owners, particularly non-residents and former short-term rental operators, this interpretation can materially affect the Portuguese tax cost of a sale.

Need advice on the sale of Portuguese property previously used in a business?

GoalSeek advises Portuguese residents, non-residents, expatriates and international property owners on Portuguese capital gains taxation, Category B income, cross-border property transactions and IRS compliance.

Where a property has previously been used for Alojamento Local or another business activity, the tax analysis should be completed before the sale whenever possible, as the legal classification and timing can substantially alter the final tax liability.