Think of it this way – *you are loaning money to the bank.* and part of that loan means they have to pay interest on the loan.
in the meantime – the bank loans that money to someone else, at a higher rates of interest than they are paying you. So if the bank is paying you 3% interest, they are charging 4% on the loans they are writing. That allows the bank to pay off the loan they owe you, and make a profit.
what banks do though is advertise as “a safe place to store your money”, and offering you different interest rates (Instead of phrasing it as “can we borrow money from you so we can keep the lights on”).
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