In order to obtain a tax deduction card, an employer needs the national ID number of the person whose tax deduction card he wants. Under law, employers are only permitted to obtain tax deduction cards for persons they are going to make taxable payments to.
An employer has a right to obtain a tax card, because of their obligation to make prepayment deductions. The electronic tax deduction card contains a restricted amount of information, such as details of tax table, tax rate and tax municipality.
Some employers do not have fully up-to-date information in their payroll systems and it can happen that they obtain tax cards for persons who are not currently their employees.
If you discover that an employer other than your current one has obtained your tax deduction card, you should contact them to get them to rectify this.