My guess is deals with the issuing banks / companies.
Here's my thought process: the parties running rewards programs are doing it because they want people maximizing their spend a) on the card, because spending -> interest and b) on the items / shops / etc that they are incentivizing, because they have backend deals (such as being the airline that is incentivized, or receiving affiliate fees from retailers with low costs).
It doesn't even seem too ridiculous to me that they would be able to work out 0 fee / passthrough rates with the bigger players based on those incentives, though it would probably be a first!
Here's my thought process: the parties running rewards programs are doing it because they want people maximizing their spend a) on the card, because spending -> interest and b) on the items / shops / etc that they are incentivizing, because they have backend deals (such as being the airline that is incentivized, or receiving affiliate fees from retailers with low costs).
It doesn't even seem too ridiculous to me that they would be able to work out 0 fee / passthrough rates with the bigger players based on those incentives, though it would probably be a first!