Knowledge base

Practical guides on the Belgian withholding obligation.

nsso·9/1/2026·7 min read

How to find your supplier's NSSO number: a guide for clients

Finding your supplier's NSSO number is the first step of every withholding obligation check. Here are the four most reliable ways, plus the pitfalls to avoid.

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nsso·8/20/2026·7 min read

Checking social security debts: step by step

How to correctly check a contractor's social security and tax debts: what you need, how to read the result and what to do when an amount must be withheld.

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