| Ameren | holding company, public company | 1997 |
| Belden Incorporated | business, public company | 1902 |
| Build-A-Bear Workshop | business, public company | 1997 |
| McDonnell Aircraft Corporation | aerospace manufacturer | July 6, 1939 |
| McDonnell Douglas | former entity, defense contractor, aerospace manufacturer | 1967 |
| Missouri Pacific Railroad | railway company, business | 1917 |
| Monsanto | multinational corporation, public company | 1901 |
| Peabody Energy | business, enterprise, public company | 1883 |
| Ralston Purina | trademark, business | 1894 |
| Sigma-Aldrich | business, enterprise, public company, biotechnology company | 1976 |
| Washington University in St. Louis | private not-for-profit educational institution, private university | 1853 |