A fresh analysis by Belgian newspapers Le Soir and De Tijd highlights the enduring scale of Belgian wealth managed via Luxembourg. Nearly 9,800 Belgians are full or partial owners of 11,200 companies registered in the Grand Duchy, making them the third most-represented nationality in Luxembourg’s commercial register, falling behind only the French and Luxembourgers themselves.
Among these are the hundred wealthiest Belgian families, who collectively control 416 Luxembourg-based companies valued at over €91 billion.
The richest fifty families alone account for €85.5 billion, mainly through financial holdings designed to consolidate and manage their assets, thus exceeding the entire annual economic output of Luxembourg.
Billions in ‘letterbox’ companies
Tax lawyer Denis‑Emmanuel Philippe explained to Le Soir that Belgian residents overwhelmingly use Luxembourg companies to house financial assets. Despite a 2018 Belgian tax reform that reduced Luxembourg’s relative appeal, these structures remain popular.
Payouts from Luxembourg holding companies (known as Soparfi, short for Société de Participations Financières) to Belgian shareholders now trigger double taxation: a 15% withholding tax in Luxembourg and a 30% tax in Belgium.
The Belgian tax authorities have also strengthened their oversight, deploying tools like the so-called “Caïman tax” and anti-abuse provisions under the EU parent-subsidiary directive to counter aggressive tax planning.
The investigation points out that at least 307 of the companies linked to Belgium’s richest families are so-called “letterbox” entities – companies with no staff or offices, often domiciled with professional corporate service providers. Over half of these families use such companies, with these businesses holding a combined €54 billion in assets.
According to Philippe, this practice is legal, as holding companies do not require significant operational infrastructure to manage investments.
A persistent and widespread phenomenon
This trend is not new. The 2021 OpenLux investigation by Le Soir and 16 other media outlets revealed that 10,066 Belgians were then registered as beneficial owners of at least one Luxembourg company. Five years on, these numbers have scarcely changed, underlining Luxembourg’s status as a preferred destination for Belgian wealth.
The latest data obtained by Le Soir and De Tijd, which covers more than 32,000 records linking Belgians to Luxembourg companies, further confirms the stability and persistence of these practices.
While some prominent Belgian fortunes have withdrawn from the Grand Duchy, many remain firmly established, attracted by Luxembourg’s ongoing political and fiscal stability.
One of the cited examples is entrepreneur Marc Coucke. Despite declaring in 2018 that he had “nothing in Luxembourg”, Coucke since registered four holding companies in the Grand Duchy between 2022 and 2025.
These entities, though without employees, have managed hundreds of millions of euros in securities and shareholdings.
Why stay in Luxembourg?
For some heirs and long-established families, dismantling Luxembourg structures would trigger hefty tax bills in Belgium.
As Denis‑Emmanuel Philippe noted, it is also “difficult to explain to Belgian banks the origins of assets that have been held in Luxembourg for decades”, making the option of staying put all the more attractive.
