| 20th Century Studios Home Entertainment | Century City, Los Angeles | 1976 |
| 20th Television Animation | Los Angeles | 19 de maio de 1999 |
| 7-Eleven | Dallas, Irving | 1927 |
| A. O. Smith | Milwaukee | 1889 |
| A. T. Cross Company | Lincoln | 1846 |
| About.me | — | 2010 |
| Abrams Books | Nova Iorque | 1949 |
| Activision Blizzard | Santa Mônica | 10 de julho de 2008 |
| Adafruit Industries | Nova Iorque | 2005 |
| AddThis | Vienna | 2006 |
| Adient | Dublin | 31 de outubro de 2016 |
| Advance Auto Parts | Roanoke | 1932 |
| Advent International | Boston | 1984 |
| Aeria Games | Berlim | 2006 |
| Ageia | Santa Clara | 2002 |
| Agência Nacional de Detetives Pinkerton | Ann Arbor | fevereiro 1855 |
| Air Products & Chemicals | Detroit | 1940 |
| Air Tractor | Olney | 1973 |
| Airstream | Jackson Center | 1931 |
| Akamai Technologies | Cambridge, Massachusetts | 1998 |
| Alcoa | Nova Iorque | 1907 |
| Alcon Entertainment | Los Angeles | 1997 |
| Alesis | Cumberland | 1980 |
| Alexa Internet | São Francisco, Califórnia | abril 1996 |
| Alexion Pharmaceuticals | Cheshire | 1992 |
| Aliança das Indústrias Eletrônicas | condado de Arlington | 1924 |
| Allen-Bradley | Milwaukee | 1903 |
| Alltel | Little Rock | 1943 |
| Amblin Television | Universal City | 31 de julho de 1984 |
| AMC Theatres | Kansas City | 1920 |
| AMD | Santa Clara | 1 de maio de 1969 |
| Amdahl Corporation | Sunnyvale | 19 de outubro de 1970 |
| American Axle | Detroit | 1994 |
| American Eagle Outfitters | Pittsburgh | 1977 |
| American Electric Power | Columbus, Jersey City | agosto 1927 |
| American International Group | Nova Iorque | 1919 |
| American Locomotive Company | Schenectady, Nova Iorque | 24 de junho de 1901 |
| American Megatrends | Norcross | 1985 |
| American Power Conversion | West Kingston | 1981 |
| American Tobacco Company | Durham | 31 de janeiro de 1890 |
| American Tower Corporation | Boston | 1995 |
| American Wrestling Association | Minneapolis | 1960 |
| Amgen | Thousand Oaks | 1980 |
| Amkor Technology | Tempe | 1968 |
| Amlogic | Santa Clara | 1995 |
| Ampere Com | Santa Clara | 2017 |
| Amphenol | Wallingford Center | 1932 |
| Ampm | — | 1978 |