| 20th Century Studios Home Entertainment | Century City, Los Angeles | 1976 |
| 3Com | Marlborough | 1979 |
| 3M | Maplewood | 1902 |
| A. O. Smith | Milwaukee | 1889 |
| A. T. Cross Company | Lincoln | 1846 |
| AbioMed | Danvers | 1981 |
| ABKCO Records | Nova Iorque | 1961 |
| About.me | — | 2010 |
| Abrams Books | Nova Iorque | 1949 |
| Academi | Carolina do Norte, McLean | 1997 |
| Activision Blizzard | Santa Mônica | 10 de julho de 2008 |
| Adafruit Industries | Nova Iorque | 2005 |
| Adient | Dublin | 31 de outubro de 2016 |
| Adobe | São José | 28 de fevereiro de 1982 |
| Advance Auto Parts | Roanoke | 1932 |
| Aero Commander | Culver City | 1944 |
| Aerojet Rocketdyne | Palm Bay | junho 2013 |
| AeroVironment | Simi Valley | 1971 |
| Ageia | Santa Clara | 2002 |
| Air Products & Chemicals | Detroit | 1940 |
| Air Tractor | Olney | 1973 |
| Airbnb | São Francisco | 2008 |
| Akamai Technologies | Cambridge, Massachusetts | 1998 |
| Aksys Games | Torrance | 14 de julho de 2006 |
| Albemarle Corporation | Baton Rouge | 1994 |
| Alcoa | Nova Iorque | 1907 |
| Aldus | Seattle | 1 de fevereiro de 1984 |
| Alexion Pharmaceuticals | Cheshire | 1992 |
| Alfred Music Publishing | Los Angeles | 1922 |
| Alienware | Miami | 1996 |
| AlliedSignal | Morristown | 1985 |
| Allis-Chalmers | Milwaukee | 1901 |
| Allison Engine Company | Indianápolis | 1915 |
| Alltel | Little Rock | 1943 |
| Amaze Entertainment | Kirkland | 1997 |
| Amblin Television | Universal City | 31 de julho de 1984 |
| Amdahl Corporation | Sunnyvale | 19 de outubro de 1970 |
| American Axle | Detroit | 1994 |
| American Cyanamid | Wayne | 1907 |
| American Eagle Outfitters | Pittsburgh | 1977 |
| American Electric Power | Columbus, Jersey City | agosto 1927 |
| American Express | Nova Iorque | 1850 |
| 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 |
| Amgen | Thousand Oaks | 1980 |