How does Visa/Mastercard split the swipe fee with card issuers

[tndolphin]

My understanding is that merchants pay the same swipe fee for all visas or all mastercards regardless the issuers, which is lower than what Discover and Amex charge. I have been wondering how issuers and Visa/Mastercard would split the swipe fee. Doesn't this put Chase, Citi at a disadvantage when competing with Amex and Discover with the much lower swip fee revenue?

[boomhower]

I'm guessing they have their own agreements and it's not universal, i.e. the bigger the bank with more cards gets a bigger portion of the fee than small lenders.  Amex certainly gets the biggest piece of the pie by having the highest fee and getting all of it to themselves.(not outstanding agreements with the few other cards that run on Amex)  More or less the same with Discover. 

Another benefit they have is they can easily make agreements.  Like Amex with Costco and Discover with Sams Club.