Increase in risk in Belgian car insurance: what to declare, and by when?

Have you moved, changed how you use the car, or handed the wheel to a young driver since signing? That is an increase in risk, and the policy in principle asks you to declare it. The insurer then has a month to react. Left unsaid, it can cut your payout on the day a claim arrives.

Increase in risk, high-risk driver, false declaration: three notions, three moments

They get mixed up constantly. They do not start at the same time and they do not cost the same.

The first is covered in our article on false declaration. The third, on refusal and cancellation, in the one on insurance after a cancellation. This one is the second.

What does the law say, and what do contracts actually say?

The Belgian Insurance Act of 4 April 2014 requires the policyholder to report to the insurer, during the contract, any new circumstances that increase the risk (article 81 is the entry point). The text stays general. Practical detail sits in your general conditions, and it varies.

Two public sets of conditions, read for this article, set the tone. At AXA Belgium, the general conditions of 06.2020 define an increase in risk as circumstances that « aggravent d'une manière sensible et durable le risque de survenance d'un sinistre », that is, increase the risk of a claim in a significant and lasting way. At Belfius Direct, the pay-per-kilometre conditions (version 06.2026) refer to article 6 for the increase, article 5 for change declarations and article 7 for a decrease in risk.

Neither sets a number of days for declaring. The working rule is simple: early.

Which changes must you declare during the contract?

The lists published in these two contracts largely overlap:

• the use of the vehicle, when it moves from private to business, or an activity is added;
• the characteristics of the vehicle, on replacement or modification;
• the value of the vehicle, when equipment is added (AXA covers up to 1,240 euros excluding VAT of undeclared equipment, the alarm always being covered);
• the policyholder, their activities and VAT status, for fleet or business contracts;
• the declared main driver, when it changes;
• the address, which Belfius lists every time without exception;
• the transfer of ownership or registration of the vehicle abroad.

The word that matters is « lasting ». A weekend abroad or a month staying with your parents does not count. Switching the main driver from the father to a 19-year-old child does.

I never recommend a policy without reading this list, because it behaves like a list of exclusions: whatever you fail to declare becomes the insurer's argument.

The insurer has one month: four possible reactions

The period runs from the day the insurer learns of the change. Both contracts read describe the same mechanism, under different article numbers.

A worked example, purely illustrative. Your premium is 600 euros a year. On 1 March your 19-year-old son becomes the main driver. You declare it, and the insurer answers on 15 April with a premium of 900 euros. The increase runs from 1 March: 300 euros over the year, so about 37 euros to catch up for those 45 days, then 900 euros a year after that.

The last case, where the insurer lets the month slip, works in your favour. But it assumes you declared, because the insurer can only react to what it knows.

What if you declared nothing before a claim?

The contract can then shrink the payout, or send the bill back to you. The mechanisms described in the two contracts read are these.

At AXA, if a claim occurs before the new terms apply and you did not declare, or declared too late, the payout can be reduced in the proportion between the premium paid and the premium that should have been paid. Take a premium paid of 600 euros against a premium due of 900 euros, and damage of 6,000 euros: 6,000 × 600 / 900, so 4,000 euros paid. The 2,000 euro gap stays with you. This rule appears in an AXA fleet contract; the wording of yours may differ, and proportional reduction does not apply everywhere.

For third-party liability, the victim is compensated in every case, since liability cover is compulsory. The insurer then turns against you. For an unintentional omission, that recourse is capped at 250 euros in both contracts read. For an intentional omission, it covers the full net outlay, and Belfius adds the possibility of asking for the contract to be declared void.

Two practical lines. First, the difference between « oversight » and « intent » is settled on evidence: a dated email reporting the change is worth more than a thousand good intentions. Second, declaring almost never costs more than staying silent, because a 300 euro surcharge beats a payout cut by 2,000 euros.

« Risque aggravé »: the trade term, not the law's

When a broker speaks of « risque aggravé », they mean a driver whom mainstream insurers hesitate to take on: high malus, cancellation by the previous insurer, licence withdrawal, drink driving. It is not a legal category but a commercial shorthand. In France, demand for « assurance auto risque aggravé » is about nine times larger than in Belgium according to measurement tools, and the pages that show up describe French mechanisms (the AGIRA file, the Bureau Central de Tarification) that do not exist here.

In Belgium, the safety net is called the Bureau de Tarification (Tariff Bureau). For a driver refused by several insurers, it sets a premium that cannot exceed five times the lowest premium on the market for the cover concerned, with a deductible capped at three times the lowest. The file must be complete five weeks before the renewal date. The detail and the Datassur RSR file are described in the article on insurance after a cancellation.

And if your situation improves?

The mechanism works both ways. Belfius provides in article 7 that you can report a decrease in risk to ask for a lower premium: if no agreement is reached within a month of your request, you can cancel. AXA provides the same exit. It is an underused negotiating lever: remote working that cuts your mileage, a car now kept in a closed garage, a more experienced main driver. Our article on renegotiating your car insurance shows how to use it.

Six minutes to check your own conditions

Open the PDF of your general conditions and switch on search.

1. Type « aggravation » then « circonstances nouvelles » (new circumstances). Note the definition: look for the words « sensible et durable » (significant and lasting).
2. Find the list of changes to declare, often in a footnote. Compare it with your real life.
3. Search « un mois » near that chapter to confirm the insurer's reaction period.
4. Type « 250 »: the cap on recourse for unintentional omission often sits in the recourse chapter.
5. Read the payout reduction clause, often a ratio between premium paid and premium due.
6. Note the declaration procedure: letter, online form, broker. Keep proof of sending.

The step-by-step reading of particular conditions gives the general method for navigating these documents.

Common situations: declare or not?

To compare what contracts require over their lifetime, the comparison tool lines up the guarantees and the ranking of the best car insurers sets out what each company covers and refuses. The quiz helps you spot which situations weigh on your profile.

Belgian contracts are governed by the Insurance Act of 4 April 2014. In a dispute over an increase in risk, the Insurance Ombudsman, the free Belgian complaints service for insurance customers, examines complaints, and the FSMA, the Belgian financial services and markets authority, supervises the conduct rules of insurers and intermediaries. The conditions cited are public: the AXA Confort Auto Fleet general conditions (06.2020) and the Belfius Direct pay-per-kilometre general conditions, retrieved on 18 October 2026.

This site informs and compares. It is not an insurance intermediary and gives no individual recommendation: your particular conditions, and only they, decide.