Is the money paid annually by the company to its employees, referred to as "interest," unlawful?

If what the company pays to its workers is lawful and originates from a lawful source, then it is permissible and considered a bonus. The benefit does not necessarily have to be usurious; it could stem from profits and permissible activities. However, if the money results from an unlawful investment or depends on usury, then it is not permissible to take it.