Banks in Nigeria make money primarily by earning interest on loans and other forms of credit extended to customers, as well as by charging fees for various services such as account maintenance, ATM withdrawals, wire transfers, and other transactions.

In more detail, here are some of the key ways that banks in Nigeria make money:

1. Interest income: Banks earn interest on loans and other forms of credit that they extend to customers, such as mortgages, personal loans, and credit cards. The interest charged on these loans is typically higher than the interest paid on deposits, allowing banks to earn a profit on the spread between the two rates.
2. Non-interest income: Banks in Nigeria also earn revenue from various fees and charges that they impose on customers for services such as ATM withdrawals, wire transfers, and account maintenance. These fees can vary widely depending on the bank and the type of service, but they can be a significant source of revenue.
3. Investments: Banks in Nigeria may also invest in various financial instruments such as stocks, bonds, and other securities. These investments can generate income through dividends, interest payments, or capital gains.
4. Foreign exchange operations: Some Nigerian banks engage in foreign exchange operations, buying and selling currencies to earn a profit on the spread between the buy and sell rates.
5. Digital banking: The rise of digital banking in Nigeria has opened up new revenue streams for banks, such as offering mobile banking services, online payment platforms, and other fintech solutions.

In order to keep their businesses running, Nigerian banks must also manage their costs and maintain a sound financial position. This includes managing risks associated with lending, investing, and other activities, as well as ensuring adequate liquidity and capital reserves to meet regulatory requirements and respond to unexpected events.