What is the ruling on an additional percentage requested by an employee for himself without his company's knowledge?

This employee is a special agent entrusted with his work, and his hand is a hand of trust. Therefore, he is not permitted to act in it except with the permission of his employer, nor is he permitted to accept a commission except with his permission. If he takes it without his knowledge, it is considered among the forbidden gifts to workers, and he must return it to the company and repent to Allah.