Banks earn a lot from the sale of collateral and business lending. I for example know that many banks have income even from loans on 1+ day. Also, the income of banks depends on the country in which they are located. In poor countries, credit rates are higher and the population is poor, so they are more likely to use credit.There are so many ways in which banks earn a lot of income, interest income comes from borrowing customers in loans, large interest income depends on the amount of loans disbursed and the interest rate set, the role of the bank as an intermediary institution that collects funds from the community and channeling funds in the form of credit to the business sector or individuals in need, and many more that can be profitable for my bank only illustrate small samples, and others have answered more.