The depression and bank failures that happened in the 20's are what lead to the FDIC and the insurance that every one's bank account has. As long as the account is under 100k (IIRC, it may be more now) the account is fully insured against loss by the bank failure. A bank is a business, like any other and can go out of business but the customers money has a federally mandated insurance policy on it, up to a point.