Want to earn some extra money? Not like that.

Preparing tax returns for a fee alongside your job at the Tax and Customs Administration? The subdistrict court put a stop to that.

In a ruling dated January 22, 2026, the subdistrict court ruled that an employee of the Tax and Customs Administration had acted in violation of the prohibition on secondary employment and had acted in a seriously culpable manner by preparing tax returns in the evenings for a fee and consulting his employer's internal systems in the process.

What happened?

The Tax and Customs Administration suspected that an employee was preparing tax returns and providing tax advice in the evenings in exchange for payment. The employee was also said to be consulting the Tax and Customs Administration's internal systems. 

The Tax and Customs Administration invited the employee in question for a meeting. During this meeting, the employee stated that he had repeatedly provided tax advice to acquaintances and family members in exchange for payment. It later emerged that the employee had helped more people. After this meeting, the employee was suspended in the interests of the organization on suspicion of a serious breach of integrity. 

In these proceedings, the State requested that the employment contract with the employee be terminated because the employee had acted in a seriously culpable manner.

The subdistrict court ruled that the employee had acted in a seriously culpable manner because he:

• had acted in violation of the prohibition on secondary employment;
• it has been established that he accessed the Tax and Customs Administration's systems without authorization, and
• it has been established that he used the information obtained from the systems without authorization for his prohibited tax advice.

The employee also knew that what he was doing was not permitted. The Tax and Customs Administration's intranet clearly states that you may only consult the internal systems to the extent necessary for your work. It also states that the use of confidential information for, among other things, secondary activities is considered a serious breach of integrity. It should be noted that when logging in, the employee was repeatedly shown a message warning him that use of the systems would be logged and misuse would be punished.

In addition, the subdistrict court emphasized the special position of the Tax and Customs Administration in society, the large amount of data it holds on citizens and businesses, and the fact that Tax and Customs Administration employees have a special responsibility to ensure that citizens' trust in the Tax and Customs Administration is not undermined.

The subdistrict court concluded that the employment contract was terminated with immediate effect due to seriously culpable conduct and that the employee was not entitled to a transition payment, with the employee being ordered to pay the costs of the proceedings.

Although secondary employment is permitted in principle, an employer may still prohibit certain secondary employment on objective grounds. Do you have questions about secondary employment by your employee or would you like to know whether your policy is still up to date? Please contact Dennis Oud, Tessa Sipkema and Elke Hofman-Bijvank. 

You can read the full ruling here.