| Onsemi | Scottsdale | June 18, 1992 |
| OQO | San Francisco | 2000 |
| Oshkosh Corporation | Oshkosh | 1917 |
| Packard Bell | Chatsworth | 1926 |
| Padlet | San Francisco | December 1, 2012 |
| Palantir Technologies | Miami | 2003 |
| Palm, Inc. | Sunnyvale | 1992 |
| Pantone | Carlstadt | 1962 |
| Parallels | Renton | 1999 |
| Peabody Energy | St. Louis | 1883 |
| Peavey Electronics | Meridian | 1965 |
| Pennzoil | Houston | 1963 |
| People Incorporated | New York City | July 28, 1986 |
| Perforce Zend | Minneapolis | 1999 |
| Phillips 66 | Westchase | May 1, 2012 |
| Pioneer Hi-Bred | Johnston | 1926 |
| Pitney Bowes | Stamford | 1920 |
| PNC Financial Services | One PNC Plaza | 1982 |
| Polaris | Medina | 1954 |
| Praxair | Danbury | 1907 |
| Precision Manuals Development Group | Alexandria | 1997 |
| Principal Financial Group | Des Moines | 1879 |
| Qlik | King of Prussia | 1993 |
| Quora | Mountain View | June 21, 2010 |
| R. J. Reynolds Tobacco Company | Winston-Salem | 1874 |
| RatPac-Dune Entertainment | Los Angeles | 2006 |
| RE/MAX | Denver | 1973 |
| RealNetworks | Seattle | 1993 |
| Red Digital Cinema Camera Company | Lake Forest | 2005 |
| Red Wing Shoes | Red Wing | 1905 |
| Regions Financial Corporation | Birmingham | July 13, 1971 |
| Ring of Honor | — | 2002 |
| Roku, Inc. | Los Gatos | October 2002 |
| Royal Caribbean Group | Miami | 1997 |
| Sara Lee Corporation | Downers Grove | 1939 |
| Seagate Technology | Cupertino | 1979 |
| Shimmer Women Athletes | Illinois, Chicago, Berwyn | November 6, 2005 |
| Shure | Niles | 1925 |
| Shutterstock | New York City, Empire State Building | 2003 |
| Silver Lake | Menlo Park | 1999 |
| Sinclair Broadcast Group | Hunt Valley, Cockeysville, Union Valley | 1971 |
| SLB | Houston | 1926 |
| Sonos | Santa Barbara | 2002 |
| SoundHound | Santa Clara | September 2005 |
| Southern Company | Atlanta | 1945 |
| Specialized Bicycle Components | Morgan Hill | 1974 |
| Spectrum Brands | Middleton | 1906 |
| Sprint Corporation | Overland Park | 1899 |