It's part of it. These cards deliver more value--the primary factor we consider in setting interchange rates on the merchant side. We also mandate a higher level of features to banks. We require banks to put in additional features, which costs money on these cards, and because of those requirements, which are necessary to compete with American Express—the primary reason we launched the card—we need to provide the banks that issue the cards with a higher level of interchange to offset those increased costs.
On May 14th, 2009. See this statement in context.