Belgium's total public debt stands at €692 billion, roughly 108% of GDP. However, a growing of that debt belongs to the country's regions and language communities.
The share of Belgium's debt that can be placed at the door of the country's regions and communities has "risen steadily" over the last two decades, from 8.4% in 2008 to 18.4% (€128 billion) now, according to a new investigation by the Federal Planning Bureau (FPB).
"This sharp increase raises questions about the sustainability of the public debt of the various federated entities and about the contribution they make to the budgetary challenge facing Belgium as a whole," argued the FPB.
The Bureau stress-tested the sustainability of debt levels for the Flemish and French Communities, Flanders, Wallonia, and the Brussels-Capital Region to see how they would respond to a range of scenarios.
For each entity, it provided a set of outcomes on where debt will be in the future, and how sustainable that debt level will be for each community or region to manage. The main scenario paints a worrying picture of debt levels through 2031 – especially for Brussels.
Debt levels in Brussels will be unsustainable by 2031
In the Capital Region, the Bureau sees debt as a share of available revenue moving from 250% in 2025 to 328% in 2031. This rise comes despite efforts since 2025 to reduce the deficit and the unintended consequences of the caretaker government spending no new money during the year it took to form a new Brussels government.
To compare each entity, the FBP uses "adjusted available revenue" as an indicator – namely, the amount of total revenue minus the transfer to other levels of government, adjusted for each entity. This is because there is no GDP data at the community level.
Deficits have been significant in the recent past in Brussels; the FBP noted that since 2018, the budget gap "has been high due to rising investments". In 2020, the Covid-19 pandemic pushed the deficit to 20% of available revenue, and it remained at that level until 2024.
Overall, the Bureau warned that debt levels in the Brussels-Capital Region have a high risk of becoming "unsustainable". It also cautioned that the Region will have limited room to restructure its budget through tax and spending changes as part of fiscal consolidation efforts, once debt levels reach this high.
Wallonia will have wiggle room for restructuring its budget
The Walloon Region ends in a similar place to Brussels, reaching a debt level of 327% of revenue by 2031. Sharp rises in the debt ratio since 2019 were driven by the Covid-19 pandemic and responding to the floods in 2021.
However, unlike Brussels, budget consolidation will slow debt growth, moving it from 301% of available revenue in 2025 to 327% in 2031.
Despite this, the FBP also brands the Region's debt "unsustainable". However, there is a silver lining: the Walloon Region has more room for fiscal consolidation in 2031 than Brussels or Flanders.
Meanwhile, the French-speaking community, which operates in Wallonia and most of Brussels, has its own budget but no revenue-raising power, receiving income from budget transfers.
Debt levels have "generally increased" over the last 10 years.
Between 2024 and 2026, the FBP noted that annual deficits reached 10% of available revenue. The debt ratio in 2025 was 117% of revenue, which under the FBP's central scenario, is projected to rise to 120% in 2026 and to 158% in 2031.
The risk of unsustainable debt remains high for the French-speaking community, and without tax-raising power, its ability to consolidate budgets is low.
A debate about the community's financing model occasionally resurfaces, with the mayor of Charleroi, Thomas Dermine (PS), recently branding the model of two governments and two parliaments as "inefficient and obsolete".
Flanders has a low risk of having unsustainable debt in 2031
In sharp contrast to Belgium's other regions and communities is Flanders (and the Flemish community). At the start of the recent crisis era, it had a low debt ratio until 2019, after which it rose in response to the Covid-19 pandemic and energy crises.
The debt ratio is expected to stabilise from 2027 as lower budget deficits (just 3% from 2028 onwards) smooth the debt path. However, in 2031 debt as a share of revenue will be 118%, but with room to manage – the FBP gave the Region a "low risk" of having unsustainable debt by this date.
While the Federal Government aims to reduce the overall budget deficit, keeping one eye on the path of Region and Community debt and deficit levels will be important if Belgium is to safely meet its EU budget deficit targets.
