Belgian guarantee law changed fundamentally on 1 January 2026 and existing templates are likely outdated.
Belgium’s guarantee reforms have flipped fundamental assumptions. Guarantees now default to accessory guarantees rather than autonomous or first-demand guarantees. Courts favor guarantors when terms are unclear. “All sums” guarantees without caps are limited to obligations existing at signature — which may be zero if no obligations had yet arisen at that time. Creditors face new mandatory information obligations. Guarantors can now terminate indefinite guarantees on 45 days’ notice. Whilst much of the regime is supplementary law that parties can contract around, some provisions are imperative and cannot be waived.
Which guarantees are affected?
Every guarantee subject to Belgian law provided from 1 January 2026 must comply with the new regime. Guarantees signed before that date remain governed by the old regime, including for all future consequences (such as future payment obligations, amendments to the underlying contract, and enforcement actions), unless the parties expressly agree to apply the new law. This means a guarantee signed in December 2025 for a 10-year lease continues under old law for the entire lease term unless you and the guarantor mutually agree otherwise.
The law does not specify whether material modifications to pre-2026 guarantees (such as substantially increasing the cap, changing the guarantee’s nature, or adding new covered obligations) create a “new” guarantee subject to the new regime. Exercise particular caution with amendments, novation, and extensions.
Whether you are a landlord, tenant, developer, lender, or guarantor, your existing templates require immediate review. Below is your essential guide to the new rules and how to draft accordingly.
1. Guarantee Now Presumed Accessory
A fundamental question arises in every guarantee: does the guarantor pay on demand, no questions asked? Or only when the principal debtor has genuinely failed to perform?
- Autonomous guarantees (also called “guarantee on first demand” or “abstract guarantee”): require immediate payment upon written request, regardless of whether the debtor actually defaulted or the claim is valid; or
- Accessory guarantees (also called “dependent guarantee”): the guarantor’s obligation tracks the principal debtor’s obligation.
Ambiguous wording has fuelled costly disputes for years. The new Belgian law now tilts the scales decisively: every personal security is presumed to be an accessory guarantee unless the creditor proves the parties agreed to an autonomous guarantee. The true intention of the parties prevails.
Moreover, Belgian law introduces a pro-guarantor interpretation rule: when courts face doubt about the scope of any guarantee, whether autonomous or accessory, they must adopt the reading most favourable to the guarantor.
What this means for drafting:
- Simply calling it a “guarantee” or “guarantee on first demand” or excluding the Belgian law provisions on accessory guarantee (articles 2011 to 2039 of the old Civil Code, replaced by articles 9.1.1 to 9.1.34 of the new Civil Code) is insufficient. The creditor must demonstrate that the parties truly intended autonomous payment obligations.
- Courts will examine the substance, not the title. If the wording ties the guarantor’s obligation to the debtor’s actual breach, you have an accessory guarantee, regardless of what you call it.
- That said, the Belgian legislator has clarified that an autonomous guarantee remains autonomous even if it refers to the underlying contract or requires evidence of default.
Practical takeaway: For autonomous guarantees, use explicit language (“The Guarantor unconditionally undertakes to pay on first written demand without reference to any defences available to the Debtor“) and expressly waive all defences linked to the underlying obligation.
2. Accessory Guarantees: Enhanced Protection and Stricter Requirements
An accessory guarantee rises and falls with the principal obligation. If the principal obligation is void or extinguished (by payment, limitation, or otherwise), the guarantor’s obligation automatically lapses. The two are inseparable.
2.1. New protection for guarantors against post-signature amendments
A critical new safeguard protects guarantors from being blindsided by changes made after they sign. If the creditor and principal debtor later agree to increase the guaranteed obligations, worsen the terms, or accelerate payment, the guarantor remains liable only for the original obligation as it existed when the guarantee was provided. However, this protection does not apply to “all sums” guarantees, where the guarantor has expressly accepted liability for all existing and future obligations within the agreed limits.
Example: if a landlord and tenant increase rent after the guarantee is signed, the guarantor remains liable only for the original rent, unless it is an “all sums” guarantee.
Practical takeaway: Always obtain the guarantor’s formal consent for any amendment to the principal obligation or expressly stipulate that the guarantee covers “all obligations” (see point 2.2.)
2.2. New requirements for “all sums” guarantees
Accessory guarantees commonly cover future obligations in real estate and corporate transactions, including rent guarantees for long-term leases, contractor parent guarantees for phased projects, and deferred payment security in asset deals. The new Belgian law confirms that guarantees may validly cover future obligations but introduces conditions to protect guarantors against unlimited exposure.
- Sufficient determinability: The covered obligations must be sufficiently identifiable by reference to a defined framework (e.g., “all rent and charges under the Lease dated [date] between Landlord and Tenant“).
- Maximum amount: Under the old law, some guarantees stated “all sums due” without imposing a cap on the guaranteed amount. Under the new rules, an accessory guarantee for “all claims” covering future obligations must state a maximum amount. If you omit the cap, the guarantee is automatically limited to the obligations existing at the date the guarantee was provided. This is a relatively severe sanction: the guarantee becomes worthless if no obligations existed at that time, which is entirely possible since it concerns a guarantee for future obligations. This requirement is imperative law, and parties cannot contractually deviate from it.
- Scope: If the guarantee is silent on scope, the guarantee for all obligations extends only to those obligations that the parties could reasonably foresee at the time they granted the guarantee. This limitation applies notwithstanding any contrary provision in the guarantee.By default, the guarantee does not extend to (parties can override all three exclusions by express agreement): (i) debts of the principal debtor’s successors or entities it later absorbs through merger; (ii) debts transferred to the principal debtor through transfer or contribution of a business activity; or (iii) claims of a predecessor creditor that arose before assignment and were not originally covered.
Understanding how guarantees respond to corporate changes is critical corporate restructuring on the debtor side (merger, acquisition, change of form) does not automatically extend the guarantee to successor obligations; express wording is required. On the creditor side, the guarantee generally follows the underlying obligation to any successor creditor. Downstream affiliate changes are excluded unless expressly covered.
Practical takeaway: Always specify a maximum amount (e.g., “up to EUR 500,000“) and define scope explicitly. Guarantors should limit coverage to specific obligations and include termination dates; creditors should expressly cover variations, renewals, corporate restructuring (mergers, transfers), and successor liabilities. As silent guarantees are construed against the creditor, avoid relying on “reasonably foreseeable” obligations and instead ensure all covered obligations are expressly defined.
2.3. New termination rights: 45 days’ notice for indefinite guarantees
A guarantee may be entered into for a fixed or indefinite duration.
The new Belgian law now provides that for indefinite guarantees, either party may terminate with reasonable notice, an imperative rule parties cannot contract out of. The statutory notice period is 45 days, unless the parties agree a shorter period.
Moreover, under the default statutory rule, the guarantor remains bound to pre-termination obligations even if they become due and enforceable at a later date. This includes, for example, damages arising after the termination of the lease or future rent instalments under a continuing lease. The parties may expressly agree otherwise.
Practical takeaway: Specify either a fixed duration or a notice period (statutory default is 45 days). Guarantors should expressly limit post-termination liability: “The Guarantor’s liability ceases entirely for all obligations arising after the effective date of termination.”
2.4. Multiple guarantors: now joint and several liable
Where multiple parties guarantee the same obligation (e.g. two parent companies for a joint venture tenant), each now assumes joint and several liability within the limits of its own obligation. This applies even if they signed separate guarantees at different times. The creditor can pursue any one guarantor for the full amount.
Loss of “benefit of division”: The guarantors lose the “benefit of division” under the new Belgian law, i.e. when multiple guarantors exist but are jointly and severally liable amongst themselves, they cannot require the creditor to split the claim equally between them.
Retention of “benefit of discussion”: Since there is no joint and several liability with the principal debtor, the guarantors do retain the “benefit of discussion”, i.e. guarantors still retain the right, as under the old Belgian provisions, to require the creditor to first pursue and exhaust the principal debtor’s assets before claiming against the guarantors.
This means the creditor must pursue reasonable enforcement measures against the principal debtor first, such as formal demands, attachments, or court proceedings, before turning to the guarantors. Only after taking these steps may the creditor turn to the guarantors.
Exceptions: The creditor is not required to pursue the principal debtor when it is manifestly impossible or excessively difficult to obtain payment from the principal debtor. This exception applies in particular when the debtor is subject to bankruptcy, judicial reorganisation, collective debt settlement, or liquidation, or if the debtor is domiciled abroad and enforcement would be impractical.
The benefit of discussion does not apply when the guarantor is jointly and severally liable with the principal debtor (not just with other guarantors) or when the parties have otherwise agreed.
Practical takeaway:
- Creditor (e.g. landlord): you can pursue any one guarantor for the full guaranteed amount (up to its cap), without having to chase all guarantors proportionally. However, guarantors retain the right to require you to first pursue the principal debtor. To avoid enforcement delays, expressly state in the guarantee: “The Guarantor waives the benefit of discussion and may be pursued directly without the Creditor first pursuing the Principal Debtor.”
- Guarantor (e.g. parent company of the tenant): you risk paying the entire liability, then having to recover contribution from co-guarantors. Before signing, verify whether other entities have also guaranteed the same obligations, your exposure may be greater than anticipated.
However, the guarantors who guarantee the same obligation have recourse against each other in proportion to each party’s share. The share of each guarantor is determined by the fraction of the maximum risk assumed by that guarantor and the sum of the maximum risks assumed by all.
2.5. New notification and information obligations on creditors
The new law introduces two important duties for creditors:
- Notice of default: When a creditor puts the principal debtor in default, it must simultaneously notify the guarantor. This allows the guarantor to assess when they will have to perform and what additional costs they can avoid by paying the principal debt immediately.The guarantor does not need to receive a copy of the formal notice of default itself. However, the creditor must communicate the essential information to the guarantor, including (i) any additional payment deadline, (ii) the amount of costs to be incurred (if specified) and (iii) other key detailsThe form of communication may differ from the formal notice sent to the debtor.
- Information on request: The creditor must inform the guarantor, upon request and without delay, of the amount of the guaranteed obligation. This allows guarantors to monitor exposure and assess whether the principal debtor is performing properly.
Consequences of non-compliance: Whilst the law does not explicitly clarify the consequence of non-compliance, costs that accrue between the notice of default to the principal debtor and the moment the guarantor is notified cannot be recovered from the guarantor if the guarantor was not properly informed. Additionally, failure to comply could expose the creditor to liability for damages caused by the lack of timely information. Parties may deviate from this requirement as it is supplementary law.
3. Recognition of the Autonomous Guarantee
Autonomous guarantees are now expressly recognized and regulated by Belgian law. An autonomous guarantee is one where the validity, scope and continuation of the guarantee are independent of the underlying obligation. These are common in construction/contractors’ bonds (performance bonds, advance payment guarantees), lease deposits and development agreements with milestones.
3.1. How to call an autonomous guarantee (and when guarantors can refuse)
When a creditor calls an autonomous guarantee, the guarantor must:
- Check compliance of the payment request with the guarantee terms (and only the guarantee terms, the guarantor cannot investigate the underlying contract or whether the debtor actually defaulted).
- Promptly inform the creditor whether the request complies.
- Pay or refuse within 7 working days of receiving the written demand, either pay or give reasons for any refusal. The guarantor is liable for damage if it breaches these obligations. The guarantor may refuse payment only if the demand is manifestly abusive or fraudulent. The guarantor (or principal debtor) bears the burden of proving the abuse is obvious beyond reasonable debate.
Examples of manifest abuse include a landlord demanding rent that the tenant is lawfully withholding due to the landlord’s serious and undisputed breach (e.g. roof collapse rendering premises unusable), or a developer demanding payment under a performance bond for alleged defective works, when the developer has already issued a formal certificate of practical completion confirming that all works have been completed in accordance with the specification and to a satisfactory standard.
3.2. Non-transferability until called
An autonomous guarantee is personal to the creditor. The creditor cannot transfer it to a new creditor without the guarantor’s consent (e.g., on sale of leased premises, assignment of development agreements, or corporate restructuring).
To anticipate assignment, include a transferability clause in the guarantee with the guarantor’s prior consent.
Exception: Once the guarantee is called and the guarantor’s payment obligation is triggered, that payment claim (the proceeds) can be assigned or pledged by the creditor.
After payment, guarantors have statutory recourse and subrogation rights against the principal debtor.
4. How to Ensure Guarantee Compliance
In light of these comprehensive reforms, you must take proactive measures at the drafting stage to create resilient guarantee arrangements:
- Include explicit classification language that addresses whether the guarantee is accessory or autonomous, ensuring that the substance of the provisions (not merely labels) supports your intended structure and that you can meet the burden of proof should classification be challenged.
- Define the scope precisely: clearly enumerate covered obligations (rent, service charges, damages, legal costs, etc.) rather than relying on generic “all sums” language that may create ambiguity or trigger mandatory cap requirements.
- State maximum amounts for accessory “all sums” guarantees covering future obligations, as guarantees lacking such caps are automatically limited to obligations existing at the date the guarantee was provided (which may render them worthless if no obligations existed at that time).
- Incorporate termination provisions for indefinite guarantees that specify notice periods (the statutory default is 45 days), delivery methods, and the scope of post-termination liability (existing obligations only, or also future installments of continuing obligations).
- Draft multi-guarantor provisions that recognize not only joint and several liability, but also specific mechanisms for recourse allocation, proportional share calculations, and coordination amongst co-guarantors.
- Refine autonomous guarantee language to include explicit waiver of defences, first-demand payment obligations, and limitations on the guarantor’s right to refuse payment (manifest abuse or fraud only).
- Address corporate restructuring (mergers, transfers, assignments) and ensure successor liability is expressly captured where intended.
For further information, please contact:
Cedric Berckmans, Partner, Bird & Bird
cedric.berckmans@twobirds.com
