Whether you like it or not, HR and fleet strategies are about to be rewritten. The federal Mobility Budget is expected to become mandatory for all employers who offer company cars in the course of 2026. The official decision is still pending but rumour has it that it July 2026 will most likely be the enforcement date.

Here’s our share of warning though: waiting for the final text is the fastest way to end up in tax chaos. The preparation in itself is already requiring a bit of preparation and if you want a clean transition (legally, fiscally, and operationally) your planning should have already started.

Let’s see how we can prepare you in terms of tax, compliance and implementation.

From optional experiment to mandatory strategy

The Mobility Budget lets an employee exchange their right to a company car for a budget equal to the real TCO (total cost of ownership): lease, maintenance, insurance, energy, taxes… basically everything car costs related.

That budget can then be spent across three pillars:

1. Pillar 1 — keep the car but swap to an electric one
2. Pillar 2 — sustainable mobility + certain housing/commuting costs
3. Pillar 3 — leftover amount cashed out with a special employee contribution (~38%)

Tip: Still need a car? Keep it small and combine with a pillar 2 mobility budget

The logic behind this budget implementation is simple: less traffic, fewer emissions, and more freedom in how employees want to commute.

This regulation will allow for a complete redesign of fleet, HR policy, payroll flow, tax control and mobility governance, but also is (and always has been) a real talent magnet.

Pillar 2 and housing costs in 2026

Let’s address the elephant in the room. You might have read or heard about it, there is talk of reviewing the “housing allowance” part of Pillar 2.

Currently, employees can use part of their mobility budget to cover rent or mortgage payments if the home is near the workplace or improves the commute. Policymakers and advisors are concerned that:

• It risks being perceived as a disguised, tax-free salary increase rather than a mobility measure.
• Housing reimbursements may be too generous compared to other sustainable mobility options
• It may inadvertently incentivize employees to work more from home more than 50% of the time,
• It potentially shifts the mobility budget away from its core purpose which was to fund eco-friendly transportation.

No final decision has been made, but the housing component is absolutely under review. HR teams should avoid design their 2026 policy assuming generous or unchanged housing reimbursements.

Preparing for taxes: What should you start doing now?

Here’s what you need to start before any law is officialised and how to do it:

1. Calculate TCO correctly

Your entire tax model depends on it: the TCO defines the size of the mobility budget. Any errors will mean long-term fiscal issues.

This is what it should include:

• lease cost
• insurance
• maintenance and tyres
• energy/fuel
• CO2 solidarity contribution
• telematics or service fees
• VAT deductibility impact
• non-deductible costs
• management/administration fees

Having some difficulties? Download our free TCO calculator here

2. Map the fiscal treatment of each pillar

Not all pillars are created equal in the eyes of the taxman. Let's first decipher the three pillars of the mobility budget. 

Pillar 1: Tax-friendly for EVs

Budget for an electric company car remains tax efficient but must follow new CO₂ reduction rules. Read more about Pillar 1 EV tax benefits in 2026 in our article here or watch the on-demand webinar here.

Pillar 2: Tax-exempt if conditions are met

If properly documented and justified, most sustainable mobility reimbursements are exempt from:

• payroll tax
• employer social security
• employee social security

Pillar 3: Taxed via 38.07% contribution

This is only the mandatory cash-out from the employer to the employee, of the remaining mobility budget (reduced by a fixed solidarity contribution of 38.07%)

3. Prepare your payroll system

The mobility budget introduces:

• New payroll classifications: Payroll software needs to recognise new types of payments that didn’t exist before via specific codes so the system knows which items are taxed, which items aren’t, and how they should show up on payslips.
• New exemptions: if processed correctly (the correct exemption codes) certain mobility expenses are exempt from income tax and social security.
• New contribution types: as previously mentioned, the pillar 3 of the mobility budget isn’t tax-free.
• Monthly reconciliation: This is to make sure the numbers add up every month to avoid over-reimbursements or accidental taxable benefits creation.
• Annual settlement for remaining budget: similar to closing the books by settling the final amount so tax and social security are correct.

Your payroll software must be configured to track each expense type per pillar (especially Pillar 2, where controls are important). At Mbrella, your mobility budget is integrated with your payroll, whatever system you use. Check out our pricing here

4. Turn your car policy into a tax-compliant “mobility policy”

You’re thinking of just updating your existing car policy? Don’t. A mobility budget policy is different and requires:

• new eligibility rules
• tax-compliant spending rules
• evidence requirements for reimbursements
• aligned clauses in employment contracts
• transparent transition rules

Following the redaction of your mobility policy, there are a few other steps to follow to make sure everything is compliant. Check out the 5 steps here.

Need help in writing your mobility policy? Have a look at our template

5. Build a tax-safe audit trail

With the mandatory implementation and the coalition reviewing the whole process, we should expect future compliance controls in the coming years.

Make sure you have a system that tracks:

• all supporting documents for mobility expenses
• commuting justification
• proof of reimbursed housing following the rules
• monthly use and remaining balance
• internal communication and employee validation

Documentation and communication are key.

The early bird catches the worm

Beyond compliance, there are other strategic wins if you start early:

• Optimise your costs: By recalculating TCOs and reviewing fleet necessity, companies can finally right-size their vehicle park. You’ll also avoid last-minute rush implementation costs.
• ESG & employer positioning: The implementation of a mobility budget is an easy win for sustainability reporting and talent attraction.
• Employee experience: A modern compensation package that will win their heart, and attract talents!

The mandatory mobility budget will likely be from July 2026 (but not officially confirmed). No matter what the final text looks like, the implementation process will remain the same and companies that start preparing today will be the ones that avoid fiscal headaches tomorrow

Interested in knowing more?

→ Watch our on-demand webinar about the mobility budget (NL or FR)

→ Talk to our experts