Can EU officials claim Belgian mortgage tax relief for income year 2025 (assessment year 2026)?

An EU official’s Belgian mortgage tax relief depends on tax residence, the non-resident category and the loan regime. An exempt EU salary can affect the 75% professional-income test without itself becoming taxable. Separately, the federal interest deduction for property other than the own home ends from income year 2025, including for existing loans. The answer depends on the individual situation.

Figures below are illustrative; unless expressly identified as historical, they concern income year 2025, assessment year 2026.

Tax residence comes before the mortgage boxes

Living in Belgium does not necessarily make an EU official a Belgian tax resident. Under Article 13 of Protocol No 7 on the privileges and immunities of the European Union, an official who moves to another Member State solely to perform EU duties may retain the tax domicile held on entering EU service.

Where its conditions apply, this is a legal rule, not an option to choose whichever residence produces the lowest tax. An official can therefore live in Belgium while remaining subject to Belgian non-resident income tax on Belgian-source income.

The extension to a spouse depends, among other things, on whether the spouse carries on a separate gainful occupation. A working spouse can have a different tax status. Marriage alone does not establish that both spouses have the same return, reliefs or reporting obligations.

The source analysis also identifies €13,460 of exempt professional income for income year 2025 as relevant to separate assessment under Article 126 of the Income Tax Code 1992. Residence and separate assessment must both be examined; they should not be inferred solely from the form previously received.

Why the 75% test matters for non-residents

The source analysis applies the following professional-income test:

Belgian-taxable net professional income ÷ total relevant net professional income ≥ 75%.

The denominator includes Belgian-taxable professional income, relevant Belgian-source exempt professional income and foreign professional income. Real estate income does not enter this calculation.

In the illustrative situation, an official has exempt EU remuneration and Belgian rental income, but no professional income taxable in Belgium. On the interpretation adopted in the analysis, the numerator is zero and the denominator includes the exempt salary: the result is 0%, not 75%. Rental income cannot bring that ratio up to 75%.

The analysis relies on Articles 243 and 243/1 of the Income Tax Code 1992 to distinguish the reliefs available to different non-resident categories. Failure to meet the test can exclude mortgage-related federal reductions, regional advantages and the basic tax-free allowance. Specific treatment for residents of France, the Netherlands and Luxembourg must be checked separately.

Which return codes are relevant?

In the non-resident return, Section III concerns personal details and family circumstances; Belgian property income appears in Section IV. In the resident return, property income appears in Section III instead. Confusing the two forms can lead to a wrong answer before any calculation starts.

The source analysis cites the following category codes from earlier non-resident forms:

The first group can access qualifying regional sections; the first two groups can access the relevant federal sections, subject to each relief’s conditions. A category code records eligibility—it does not create it.

The source also refers to the social-security questions under 1082-82 / 1083-81, and to reporting relevant exempt remuneration in Section XIV. These are not interchangeable with the category question.

The cited form materials include assessment years 2018, 2024 and 2025. Their codes and instructions must be checked against the assessment-year-2026 return before filing.

What changed for mortgage interest from income year 2025?

The Law of 18 December 2025, published on 30 December 2025, abolished the federal ordinary interest deduction for property other than the own home from assessment year 2026. Circular 2026/C/2 of 5 January 2026 explains that the change covers both new and existing borrowing.

Consequently, interest paid on qualifying rental-property loans can no longer be deducted from real estate income under that former regime. Existing loans do not retain the deduction through a transitional arrangement.

The reform also removes the federal housing bonus, federal building-savings reduction and reduction for additional interest discussed in the source analysis. It is distinct from eligibility for surviving regional own-home regimes.

The source identifies former interest code 1146 and federal housing-bonus codes 1370 / 1371 as removed from the 2026 form. Changing the non-resident category cannot restore an abolished relief.

Which mortgage-related reductions may still matter?

Federal long-term savings: the analysis describes a 30% reduction for eligible capital repayments on loans concluded before 1 January 2024, under code 1358. Eligible repayments are limited by the first €50,000 of the loan, indexed according to its year, and by a personal annual basket.

The source uses a basket of €2,450 per taxpayer for assessment year 2026. This is a ceiling on qualifying expenditure, not an automatic deduction or guaranteed refund. Income-related limits, other expenditure using the basket and the taxpayer’s non-resident category still matter.

Older Flemish own-home loans: for the pre-2015 regime discussed in the analysis, the basic amount is €2,280 per borrower, with a €760 increase during the first ten years only. The reduction is calculated at the applicable marginal rate, between 30% and 50%. Once that initial period has expired, the temporary increase is no longer available.

A non-resident’s access to this regional relief additionally depends on the qualifying category and regional allocation. A Belgian-resident spouse may qualify separately, subject to the loan and property conditions.

These are tax reductions, not deductions from rental income. They reduce tax only within the applicable rules and available tax liability. Multiple loans do not multiply the personal annual baskets, and a disallowed share cannot simply be reassigned to a spouse.

The cadastral income of a qualifying own home is itself exempt in the framework described in the analysis. That exemption does not establish entitlement to a mortgage tax reduction.

How Belgian rental income is calculated

The following are separate simplified illustrations, not a reconstruction of one person’s property portfolio. Use only the taxpayer’s reportable ownership share.

For residential property let to individuals for private use, the analysis uses code 1106 for non-indexed cadastral income. For income year 2025:

Taxable income = non-indexed cadastral income × 2.2446 × 1.40.

For example, a reportable cadastral-income share of €2,000 gives approximately €6,285 of taxable income. The 40% increase is applied after indexation; the calculation does not use the actual private residential rent.

For a building let to a company, the analysis identifies code 1109 for cadastral income and code 1110 for gross rent and rental advantages. The flat 40% expense deduction is capped at:

2/3 × non-indexed cadastral income × 5.63.

The taxable amount cannot fall below indexed cadastral income increased by 40%.

For example, with a reportable cadastral income of €200 and gross rent of €6,000, the nominal expense deduction would be €2,400. The cap is approximately €751, leaving about €5,249 taxable, subject to the minimum comparison. Mortgage interest does not reduce this amount under the abolished federal deduction.

Why the category can change the tax bill substantially

For a non-resident without the relevant allowance or reductions, the source illustrates taxation from the first euro. Its indicative assessment-year-2026 calculation uses 25% on the first €16,320, then 40% on the next portion, plus the 7% non-resident surcharge replacing municipal tax.

On a deliberately rounded €20,000 taxable base, those assumptions produce approximately €5,552 before the surcharge, or €5,941 after it. This illustrates scale, not a personal tax quotation.

The source contrasts that treatment with access to a €10,910 basic tax-free allowance, plus qualifying mortgage reductions. That comparison requires a full calculation: the allowance is implemented through the tax computation, and regional treatment, income and personal circumstances can change the result.

Previously accepted returns are not necessarily formal confirmation that a category was correct. A mistaken category can expose reliefs to recovery, interest and tax increases within the applicable investigation period.

EU salary exemption and foreign property are separate issues

Article 12 of Protocol No 7 protects EU remuneration from national taxation. Whether using that remuneration in an eligibility test is compatible with the Protocol requires a separate legal analysis.

The source discusses the Court of Justice’s Bourges-Maunoury and Pazdziej case law. It distinguishes an impermissible use of exempt remuneration in a wealth-tax cap from its permitted consideration in a means-tested local-tax relief. It treats a challenge to the Belgian 75% calculation as uncertain, not as an established entitlement to relief.

Foreign property raises a different residence question. A non-resident’s foreign property is outside the Belgian-source property-income base described here. A Belgian-resident spouse generally has worldwide reporting obligations, with double-tax relief depending on the relevant treaty. Reporting and treaty exemption are separate steps.

Filing dates and disputed assessments

The source anticipates a November non-resident filing and cites 21 November 2025 as the deadline for the previous assessment year. That historical date must not be reused as the assessment-year-2026 deadline.

It also mentions 30 June 2026 for paper resident returns, 15–19 July 2026 for online resident filings and an October extension for certain income types. These references concern different filing routes and should not be treated as a single deadline applicable to every taxpayer.

Check the deadline on the current return or official filing service. The form’s title, residence position and relevant-year instructions are more reliable than identifying the return from its usual filing month.

Where treatment is disputed, the analysis describes a truthful return followed, if appropriate, by a formal claim after assessment within the statutory period. It does not specify a numerical claim deadline. A written position from the competent tax office and a review of loan statements, rental figures and ownership shares can clarify the issues before a claim is considered.

Frequently asked questions

Does living in Belgium make an EU official a Belgian tax resident?

Not necessarily. Article 13 of Protocol No 7 may preserve an earlier tax domicile where its conditions are met; it is not a freely chosen tax status.

Can Belgian rental income help me meet the 75% rule?

Not under the professional-income calculation described here. Rental income is excluded, while relevant exempt professional remuneration is included in the denominator in the source analysis.

Is mortgage interest still deductible for an old rental-property loan?

The federal ordinary interest deduction described here ends from income year 2025 for existing as well as new loans. The change must be distinguished from any surviving own-home regional relief.

How much tax relief can capital repayments produce?

The source describes a 30% long-term-savings reduction, subject to an eligible-loan tranche, a personal basket stated as €2,450 for assessment year 2026 and other conditions. Neither the maximum nor access to the relief is automatic.

Can my spouse claim the relief I cannot use?

A spouse may qualify on their own eligible share, depending on their status and the loan regime. Unused personal baskets and disallowed repayments cannot simply be transferred between returns.

Do years of accepted returns prove that my category is correct?

No. An assessment without an audit is not necessarily a formal ruling on residence, the 75% test or mortgage eligibility.

Sources

The references below are retained from the source analysis. They include official materials, legal provisions reproduced by third parties, and secondary commentary. Earlier-year forms are historical references, not confirmation of the 2026 form.

1. Union Syndicale, seminar on the tax residence of EU officials (Protocol Article 13, Article 126 CIR)

2. Bazacle & Solon, exemption from the non-resident return and international officials

3. Forum for the Future, non-resident return form for assessment year 2025 and filing deadline

4. FPS Finance, filing the non-resident return (Vak III and Vak XIV)

5. FPS Finance, explanatory notes to the non-resident return, part 1, 2024

6. FPS Finance, preparation of the non-resident return, part 1, assessment year 2025

7. FPS Finance, explanatory notes to the non-resident return, part 1, categories of non-residents

8. Article 243/1 of the Income Tax Code 1992

9. Article 243 of the Income Tax Code 1992

10. Practicali, extension of the non-resident filing obligation for real estate income

11. Court of Justice of the EU, case law digest on the tax exemption of EU officials (Bourges-Maunoury, Pazdziej)

12. Circular 2026/C/2 on federal real estate taxation from assessment year 2026

13. Jubel, law of 18 December 2025 containing various provisions, tax measures

14. Lexgo, abolition of the federal interest deduction and impact on non-residents

15. Billy, Vak IX mortgage loans and long-term savings, assessment year 2026

16. NN, housing taxation in the 2026 tax return

17. Flemish Government, tax reduction for the sole and own home (woonbonus)

18. FPS Finance, indexation of cadastral income for income year 2025

19. Dewaele, taxation of rental income from private and business lettings

20. Wolters Kluwer, main tax thresholds for assessment year 2026

This article explains a general framework and is not a personalised tax opinion. Rules and indexed amounts change yearly; the correct treatment depends on the exact residence position, income, property use, loan history and applicable return instructions.

Need tax advice tailored to your situation?

Have a similar situation? Befiscal has already handled files like this one. To get a written tax analysis tailored to your own figures and situation, click the “Ask your question” chat button on the right of this page: our assistant takes over, gathers the information needed and guides you through to your personalised written analysis.