How did David Roux make his money?

AMALGAMATED Bank CHICAGO 5 American National Bank Fox Cities 6 Bank of Lincoln County 4 Citizens Bank of the Midwest 2 Citizens National Bank of Albion 8 Concorde Bank 1 DBA TAB BANK 19 First Bank of Blue Earth 4 First Lockhart Bank 4 First State Bank of Swanville 6 Granville National Bank 6 METRO Bank 25 Oklahoma Bank & Trust Company 8 Old Exchange National Bank 20 Peoples Bank of Greensboro 13 Peoples Bank of Wyaconda 7 Select Bank 8 State National Bank 14 TOWN Bank National Association 4 ValueBank Texas 6