| Böwe Bell & Howell | Wheeling | 1907 |
| C.F. Martin & Company | Nazareth | 1833 |
| Cadence Design Systems | San José | 1988 |
| Caesars Entertainment Corporation | Las Vegas, Paradise | 1937 |
| Café y té de Peet | Emeryville | 1966 |
| Calico (empresa) | San Francisco | 18 de septiembre de 2013 |
| Cannondale Bicycle Corporation | Bethel | 1971 |
| Capital Group Companies | Los Ángeles | 1931 |
| Carfax | Centreville | 1984 |
| Carhartt | Dearborn | 1889 |
| Carlyle Group | Washington D. C. | 1987 |
| Cartercar | Pontiac | 1905 |
| Case Corporation | Estados Unidos | 1842 |
| Cash App | — | 15 de octubre de 2013 |
| Caterpillar | Irving | 1925 |
| CDW | Vernon Hills | 1984 |
| Celanese Corporation | Irving | 1999 |
| Cengage Learning | Stamford | 2000 |
| Century 21 Real Estate | Madison | 1971 |
| Cerebras | Sunnyvale, San Francisco | 2016 |
| CF Industries | Deerfield, Deerfield | 1946 |
| CH2M Hill | Meridian | 1946 |
| Champ Car World Series | — | 1979 |
| Charlton Comics | Derby | 1945 |
| Charter Arms | Shelton | 1964 |
| Chicago, Rock Island and Pacific Railroad | Chicago | 1866 |
| Chips and Technologies | Milpitas | 1985 |
| Chobani | Norwich | 2005 |
| Choice Hotels | Rockville, Silver Spring | 1939 |
| CHS Inc. | Inver Grove Heights | 1931 |
| Citgo | Houston | 1910 |
| Citibank | Sioux Falls, Nueva York | 1865 |
| Citizens Financial Group | Providence | 1954 |
| Clinique Laboratories, LLC | Nueva York | 1968 |
| Coach | Nueva York | 1941 |
| CodeGear | Scotts Valley, California | 2006 |
| Coinbase | San Francisco | 20 de junio de 2012 |
| Cole Haan | Greenland | 1928 |
| Coleco | West Hartford | 1932 |
| Colgate-Palmolive | Nueva York | 1806 |
| Color Force | West Hollywood | 2007 |
| Colt's Manufacturing Company | West Hartford | 1855 |
| Combat Zone Wrestling | Filadelfia | 1998 |
| Comité Nacional Demócrata | Washington D. C. | 1848 |
| Commodore International | West Chester | 10 de octubre de 1958 |
| Comodo | Clifton | 1998 |
| Compañía Stepan | Northfield | 1932 |
| Complex | Nueva York | 2002 |