The Dutch wage tax number

If an employer is obliged to withhold or calculate and pay an employee's social security premiums (on behalf of an employee), the employer should register with the Dutch tax authorities. Upon registration of a (foreign) employer as a withholding agent in the Netherlands, the Dutch tax authorities grant a wage tax number to the company.

The wage tax number is required to file a Dutch wage tax return with the Dutch tax authorities. 

Applying for more than one wage tax number per employer is possible. Separate payrolls may be required if, for instance, the company has various businesses with their employees or, if not all, employees are covered by the same legal regime. For example, employees can fall under different collective bargaining agreements ("CAOs") depending on the nature of their activities or the legal status of the employees.