Belgian taxpayers are subject to several taxes on financial investments:
The tax on stock market transactions (“taxe sur les opérations boursières” or TOB) - for more information, you can read: What is the Belgian tax TOB? or What is the implication of TOB for Birdee users who live in Belgium?
The reporting of accounts opened abroad- for more information, you can read: How to declare a Birdee account to the Belgian authorities?
Birdee pays the TOB on your behalf.
All other income must be declared when you file your annual tax return.