Right but if BankSimple just uses 1 large slush account in each bank, then they can only be insured up to $250,000. And you are not allowed to have multiple acc

Right but if BankSimple just uses 1 large slush account in each bank, then they can only be insured up to $250,000. And you are not allowed to have multiple accounts at the same bank that are FDIC insured so it is not possible for BankSimple to just open up a new account every time they reach $250,000. So the only way to properly insure your money at each bank would be to open an account under your name at each bank. My guess is that you are right in that BankSimple will probably just have large slush fund account at each bank. And they will be FDIC insured "at launch" as it says on BankSimple's website. But once that account reaches >$250,000 your money is not fully insured. Now BankSimple doesn't seem so transparent after all...