USERRA's definition of “employer” includes a successor in interest. In general, an employer is a successor in interest where there is a substantial continuity in operations, facilities, and workforce from the former employer. The determination whether an employer is a successor in interest must be made on a case-by-case basis using a multi-factor test that considers the following:
    
    
        
        (a) 
         Whether there has been a substantial continuity of business operations from the former to the current employer;
     
    
        
        (b) 
         Whether the current employer uses the same or similar facilities, machinery, equipment, and methods of production;
     
    
        
        (c) 
         Whether there has been a substantial continuity of employees;
     
    
        
        (d) 
         Whether there is a similarity of jobs and working conditions;
     
    
        
        (e) 
         Whether there is a similarity of supervisors or managers; and,
     
    
        
        (f) 
         Whether there is a similarity of products or services.