If you have a corporate American Express card that you use for travel and entertainment expenses at work then you are already familiar with the concept of a commercial credit card. Selected workers are issued corporate credit cards which can be used for low-dollar value reimbursable expenses. If an employee wishes to purchase an airline ticket, office supplies or training materials they simply present their card to the supplier. There is no need for the buyer to issue a purchase order or the supplier to send an invoice. The supplier will be reimbursed by the banks via the credit card network in two to three days. At the end of each month a statement will be sent to the employee with all of the charges they have accrued through the card. The employee is then responsible for submitting the appropriate documentation to justify the expense.