Their money is being used to make investments and they're getting paid interest for it. If their deposit was above the amount insured by the FDIC then they knew it could all be lost if the bank collapsed. I wouldn't call lending more than 250k to a bank "cautious" (that's what you do when you "deposit" your money in a bank), they could have bought Treasury bonds instead. But maybe they were smart and had guessed that in this third world financial system, if your bank is too big to fail, depositors get bailed out by the government anyway.