| 20th Century Studios Home Entertainment | Century City, Los Angeles | 1976 |
| 20th Television Animation | Los Angeles | 19 de maio de 1999 |
| 23andMe | South San Francisco | abril 2006 |
| 3M | Maplewood | 1902 |
| A+E Global Media | Nova Iorque | 1984 |
| A. O. Smith | Milwaukee | 1889 |
| AbbVie | North Chicago | 10 de abril de 2012 |
| Abercrombie & Fitch | New Albany | 1892 |
| About.me | — | 2010 |
| Abrams Books | Nova Iorque | 1949 |
| Access Industries | Nova Iorque | 1986 |
| Acxiom | Wilmington, Conway | 2018 |
| AddThis | Vienna | 2006 |
| Adient | Dublin | 31 de outubro de 2016 |
| AdMob | Mountain View | 2006 |
| Adscape | São Francisco | 2006 |
| Advance Auto Parts | Roanoke | 1932 |
| Aero Commander | Culver City | 1944 |
| Aerojet Rocketdyne | Palm Bay | junho 2013 |
| Aetna | Hartford | 1853 |
| Affirm Films | Culver City | 2008 |
| Aflac | Columbus | 1955 |
| Agilent Technologies | Santa Clara | 1999 |
| Air Products & Chemicals | Detroit | 1940 |
| Akamai Technologies | Cambridge, Massachusetts | 1998 |
| Aksys Games | Torrance | 14 de julho de 2006 |
| Alcoa | Nova Iorque | 1907 |
| Alcon Entertainment | Los Angeles | 1997 |
| Alfred Music Publishing | Los Angeles | 1922 |
| Alienware | Miami | 1996 |
| Allen-Bradley | Milwaukee | 1903 |
| Allstate | Northbrook | 17 de abril de 1931 |
| Ally Financial | Detroit, Nova Iorque | 1919 |
| Amaze Entertainment | Kirkland | 1997 |
| Amazon | Seattle | 5 de julho de 1994 |
| Amazon Robotics | Massachusetts | 1 de janeiro de 2003 |
| Amazon Web Services | Seattle | março 2006 |
| AMC Theatres | Kansas City | 1920 |
| Amdahl Corporation | Sunnyvale | 19 de outubro de 1970 |
| American Bantam | Butler | 1935 |
| American Eagle Outfitters | Pittsburgh | 1977 |
| American Express | Nova Iorque | 1850 |
| American Girl | — | 1986 |
| American Megatrends | Norcross | 1985 |
| American Tourister | Rhode Island | 1933 |
| American Type Founders | Elizabeth | 1892 |
| Amgen | Thousand Oaks | 1980 |
| Amlogic | Santa Clara | 1995 |