There are actually many ways banks make money. One of the major ways is by their government backing. The Central Banks in many countries are controlled by a crooked system. They do not always print money in proportion to the amount of gold they possess. Most banks get odd bail-outs from the Central Bank. But some people might consider this as some conspiracy theories. Anyway, there are other ways too. The transaction fees they deduct consistently might mean little to the client but in the end, when accumulated, it amounts to a huge sum. Loan interests and other factors also play a big role.