More than 500,000 companies and organisations have not yet declared their "ultimate beneficiaries", L'Echo and De Tijd reported on Friday.
The deadline for registration was set for September 30. Those failing to comply risk a fine ranging from €250 to €50,000 .
The European Union obliges all member states to keep a register listing the directors of every company, association or foundation. The aim of the UBO register (for Ultimate Beneficial Owners) is to identify terrorists quickly and to fight money laundering.
An ultimate beneficiary is defined as an individual who has a 'substantial influence or control' over the company. Sufficient influence is if an individual has 25% or more shares or votes.
Accountancy and legal firms that are able to handle the registration blame burdensome bureaucratic procedures for the slow response rate.
The Brussels Times