Commercial banks earn money in a variety of ways:

1. private loan interest

2. mortgage interest

3. account maintenance fees

4. transaction fees

5. loan origination fees

6. holding securities

7. proprietary trading

8. wealth mgmt and advisory services

9. credit card interest

10. forex trading

11. underwriting services

12. investment banking (mergers and acquisition advisory, capital raising, market making

13. Loan securitization

14. mutual fund fees

15. etf trading fees

16. insurance products

17. safe deposit boxes

18. federal funds lending

19. holding government treasuries which provide a yield.

Those are some off the top of my head.