All the Major Card Issuers provide an annual rebate based on an annual volume of spend put through the various Corporate Cards (T&E, Meeting Cards, Commercial, Procurement Cards). There is also usually a initial signing bonus.

Unfortunately this money is coming from the higher merchant interchange fee's on the processing networks have for these types of cards.

There has also been a trend away from Platinum and Gold Corporate cards as this typically reduces the value of the annual rebate.