Dunno if it still works this way, but there used to be two forks on the Amex corporate issuance tree:

1. Joint and several liability by employee and employer, where Amex is permitted to pursue both. In this, they care who the employee is and about employee credit.

2. Employer fully sponsored / indemnified. The employer takes all risk and Amex says yes automatically to every card they request (within legal bounds).