Four of the largest credit card issuers in the world -- MasterCard, Visa, American Express, and Discover -- have all announced today that they're joining ISIS, a partnership of American carriers formed last year aimed at bringing mobile payment capability to phones in early 2012. Needless to say, that adds a lot of muscle to ISIS' network now that they've got the most important credit cards tied in and ready to be linked to your phone.

The move definitely complicates the power dynamic in the industry a bit: MasterCard had previously stood on stage alongside Google and Sprint at the Google Wallet event in May. Neither Google nor Sprint have joined ISIS, so it would've stood to reason that MasterCard might be aligning itself in the same camp -- instead, it looks like they'll be hedging their bets by piping into both of the American mobile payment projects with big momentum right now. With Verizon, AT&T, and T-Mobile all on board (and seemingly no exclusivity deal keeping partners from dipping their toes in other waters), it makes you wonder: is Sprint next to join up? And are Visa, American Express, and Discover all ready to play ball with Google to balance out the playing field?

Source: ISIS