How do exchange banks make money?

Ashton State Bank 2 BENCHMARK Bank 16 CenBank 13 FARMERS & MRCHS Bank LONG BEACH 11 Farmers Savings Bank & Trust 2 Federated Bank 4 First Financial Bank 3 First Heritage Bank 4 First Northeast Bank of Nebraska 1 First State Bank & Trust 5 KLEBERG Bank National Association 4 Latimer State Bank 1 National Grand Bank of Marblehead 4 OAKSTAR Bank 9 PEOPLES Bank OF AL 12 Peoples National Bank of Checotah 2 SmartBiz Bank, National Association 7 State Bank of Cold Spring 6 SUSSER Bank 15 WEST TX National Association National Bank 11