I don't know anything about what happened, but something doesn't add up. Why would a CFO of a successful company resign just because he doesn't have global banking experience? Sounds like BS.
Large organizations generally provide people at the C-level options to tender their resignation rather than hitting the news with supposed firing (or letting go). Firing connotes a lot of negativity as well as from a public relations perspective, they want to ensure that this process would generate the least amount of noise.
It's like saying that I'll be honest with you, and continue lying.