Banks are for-profit businesses, and as such, they are motivated by the desire to make money. However, banks also have a fiduciary duty to their depositors, which means they have a legal obligation to act in their best interests. This duty requires banks to invest depositor funds in a prudent and responsible manner, balancing the desire for high returns with the need to protect depositors' funds. In practice, some banks may prioritize profit over depositor interests, but this is not true of all banks. Some banks may have a more ethical approach to investing depositor funds, considering the long-term interests of both the bank and its depositors.