The employing company’s owner indirectly legally appropriates the positive and negative results of it, which the employees are jointly de facto responsible for. This is a violation of the moral principle that legal and de facto responsibility should match.

The claim that the employer has a right to these fruits of the employees’ labor based on the risk they take on is tautological. Assuming the risk means appropriating the negative fruits.

Worker coops can give non-voting shares to investors