Mastercard just released their own payment gateway.

This system appears to be a little different than the traditional (authoize.net / Verisign) payment gateway. It appears to be more like what we would consider a P2P money transfer medium, where buyers can pay businesses directly and businesses can invoice and collect payments from their customers. I guess you would call it a B2B money transfer system. There’s very little information about it currently, but I will be sure to post updates as they release more information about it. The website has some general information for buyers and for sellers.