A market that had never been measured

We start with the annual accounts these families file with the National Bank of Belgium and measure the entire market in one go. Holding by holding, with or without a family office, with or without a well-known name.

At least €135 billion

1,769 companies analysed, 4,212 filed annual accounts reviewed. 231 families with more than €100 million in financial fixed assets across 293 holdings, each checked individually. Plus 1,387 holdings with €20 million to €100 million. All measured at book value: a lower bound, not an estimate.

Ten findings. Here are four.

• 1. Belgian family capital held through holding companies amounts to at least €135 billion at book value. (chapter 1)
• 2. The typical top-level family holding has no debt, no employees, and made no distributions over five years. (chapters 2, 7 and 12)
• 7. Observable management costs only fall above €100 million, and then by a factor of thirteen. (chapter 6)
• 10. What sets the best-performing structures apart cannot be identified from their annual accounts. (chapter 10)

The other six findings cover the three types of top-level family holding, where capital is invested beneath the holding, and the single family office. Each comes with its figure and denominator.

Who it is for

For families who want to know whether their structure is typical for its size. And for everyone having that conversation: banking, private equity, wealth management, and business services.

Chapter 11 compares six figures for a structure with the quartile thresholds of its peer group: families of the same type and size. We do not publish a numbered ranking. The report includes the full methodology, with seven blind spots and their scale.

Download the Belgian Family Capital Monitor 2026

The ten conclusions, the chapter 11 scorecard, and the full methodology. Download the report (PDF)

Belgian Family Capital Monitor 2026 is published by openthebox, with Moore Belgium as knowledge partner. Presented at Family Capital Tomorrow (Mediafin, 9 September 2026). Editorial control and final responsibility rest with openthebox.