When the attribution of the use of a car to an employee is not foreseen in a written agreement, such use is not taxable on Personal Income Tax (Imposto sobre o Rendimento das Pessoas Singulares - hereinafter "IRS"), taking into consideration the wording of article 2.º, n.º3, b) paragraph 9 of CIRS. As such, most companies do not mention the attribution of the use of the vehicles to the employees in the employment contract or in any other written document.
Therefore, the situation of effective attribution of the use of company cars to employees without written documentation evidencing such attribution, although very common in Portuguese companies, might, if not adequately monitored, involve a certain degree of tax risk.
The annual taxable value regarding the use of the vehicle by the employee corresponds to the following formula: 0,75% of the vehicle's cost of acquisition multiplied by the number of months that the vehicle was used by the employee in a given year (article 24.º, n.º 5 CIRS).
In this case, the value corresponding to the use of the vehicle by the employee should be declared by the Company as employment income paid or put at the disposal of the employee and therefore this will be treat as a cost in the sphere of the Company, regarding the Corporate Income Tax Code (Código do Imposto sobre o Rendimento das Pessoas Colectivas – hereinafter “CIRC”)
Such value should also be declared by the employee for tax purposes, when filing his/her annual individual income tax return. It will then be taxable at the progressive IRS tax rates applicable to the global taxable income of the individual or family (if the employee is a Portuguese tax resident).
However, it should be noted that the value corresponding to the use of the vehicle by the employee is not subject to withholding tax (article 99.º, n.º1 CIRS), since it is expressly excluded from the scope of withholding tax on employment income.
In relation to social security payments and until now, the personal use by an employee of a vehicle of the employer entity is not, in general terms, considered as being subject to social security payments.

