20 C.F.R. § 1002.37
Can one employee be employed in one job by more than one employer?
Yes. Under USERRA, an employer includes not only the person or entity that pays an employee's salary or wages, but also includes a person or entity that has control over his or her employment opportunities, including a person or entity to whom an employer has delegated the performance of employment-related responsibilities. For example, if the employee is a security guard hired by a security company and he or she is assigned to a work site, the employee may report both to the security company and to the site owner. In such an instance, both employers share responsibility for compliance with USERRA. If the security company declines to assign the employee to a job because of a uniformed service obligation (for example, National Guard duties), then the security company could be in violation of the reemployment requirements and the anti-discrimination provisions of USERRA. Similarly, if the employer at the work site causes the employee's removal from the job position because of his or her uniformed service obligations, then the work site employer could be in violation of the reemployment requirements and the anti-discrimination provisions of USERRA.