I don't know, for a financial system you would need back up satellites ready to go at a moments notice in case of faulty anti satellite weapons tests, north korea, solar flares, etc... would be a disaster if your reliant on it.
It's certainly possible. No reason why some rich guy can't go to a company that makes satellites and have them design it. You would also need a network to maintain global coverage.
Also, how do you prevent denial of service attack if it uses a common protocol to communicate with you with no registration and stuff?