Also known as "vicarious liability."
Under the doctrine of agency (or master and servant), an employer may be liable for actions (or inactions) by employees, if the liability arises within the scope of the employment. It is imputed to the employer who has (presumably) given the employee certain powers in the employer's name.
For example, a pizza-delivery company could be liable for a vehicle collision caused by an employee attempting to make a quicker delivery, but not for injuries caused by an employee who stops at a bar and gets into a fight (outside scope of employment).