| Overbrook Entertainment | Beverly Hills, Los Angeles | 1998 |
| Owens Corning | Toledo | 1938 |
| Owens-Illinois | Toledo, Perrysburg | 1903 |
| P.A. Semi | Santa Clara | 2003 |
| Pacific Data Images | Redwood City | 1980 |
| PalmSource | Reston | — |
| Panic Inc. | Portland, Oregon | — |
| Pantone | Carlstadt | 1962 |
| Paper Mate | Oak Brook | 1940 |
| Parametric Technology Corporation | Boston | maio 1985 |
| Paramount Global | Nova Iorque, One Astor Plaza | 4 de dezembro de 2019 |
| Paramount Global Content Distribution | Santa Mônica, Nova Iorque | 1962 |
| Parker Brothers | Beverly, Salém | 1883 |
| Parker Pen Company | Newhaven, Londres | 1888 |
| Payoneer | Nova Iorque | 2005 |
| Peabody Energy | St. Louis | 1883 |
| Peavey | Meridian | 1965 |
| Peerless | Cleveland | 1900 |
| Peet's Coffee | Emeryville | 1966 |
| Penguin Random House | Nova Iorque | 1 de julho de 2013 |
| PeopleSoft | Pleasanton, Califórnia | 1987 |
| PerkinElmer | Waltham | 1937 |
| Petco | San Diego | 1965 |
| PetSmart | Phoenix | 1986 |
| Philco | Filadélfia | 1892 |
| Philip Morris International | Stamford, Lausana | 1987 |
| Phillips Petroleum | Bartlesville | 1917 |
| PhoenixEV | Ontario | 2002 |
| PIMCO | Newport Beach | 1971 |
| Pinnacle Systems | Mountain View | 1986 |
| Pioneer Hi-Bred | Johnston | 1926 |
| Pitney Bowes | Stamford | 1920 |
| Plantronics | Santa Cruz | 1961 |
| Plaxo | Sunnyvale | julho 2001 |
| Playboy Enterprises | Los Angeles | 1953 |
| Powell's Books | Portland | 1971 |
| PPG Industries | Pittsburgh | 1883 |
| PR Newswire | Manhattan | 8 de março de 1954 |
| Product Red | Nova Iorque | 2006 |
| PRS Guitars | Stevensville | 1985 |
| Prudential Financial | Prudential Headquarters | 1875 |
| Pyra Labs | São Francisco | 1999 |
| Qorvo | Greensboro | 2015 |
| Quiksilver | Huntington Beach | 1969 |
| Rainforest Cafe | Houston | 1994 |
| Ramada | Phoenix | 1953 |
| Rasmussen Reports | Asbury Park | 2003 |
| RC4WD | São Francisco | 2001 |