| ACW Solutions | Oregon |
| ACwebMarketing | Oregon |
| Acxiom, LLC | Arkansas |
| Ad Astra Diagnostics, Inc. | North Carolina |
| Ad Astra Ventures | |
| Ad Badger | Texas |
| Ad Buying Network, Inc. | Georgia |
| Ad Hoc | District of Columbia |
| Ad Hoc | District of Columbia |
| AD HOC Electronics | Utah |
| Ad Leverage | |
| Ad Peeps | North Carolina |
| Ad Ventures Design & Marketing | Arizona |
| Ad Vice Marketing | |
| Ad Wizards | Texas |
| Ad-Mail, Inc. | Oregon |
| Ad-Tech Medical Instrument Corporation | Wisconsin |
| AD/Solutions Group, Inc. | Illinois |
| AD60, Inc. | New York |
| Ada Conformity Assessment Authority | Wisconsin |
| Ada Developers Academy | Washington |
| Adacel Technologies Ltd | Florida |
| AdaCore | New York |
| AdAction | Colorado |
| Adaera, LLC | Pennsylvania |
| Adafruit | New York |
| Adage Technologies | Illinois |
| Adagene | California |
| Adager Corporation | Idaho |
| Adagio Medical, Inc. | California |
| Adagio Tech, LLC | Texas |
| Adalo, Inc. | Missouri |
| Adam Auton | California |
| Adam Enfroy Ventures, LLC | |
| Adam Fard Studio | New York |
| Adam Fisher-Cox | New York |
| Adam Technologies, Inc. | New Jersey |
| Adam Weston | California |
| Adam's Electronics | California |
| Adamant Online Store | Ohio |
| Adamas Optics, LLC | Idaho |
| Adams Bank & Trust | |
| Adams Community Bank | |
| Adams Consulting Group, Inc. | Georgia |
| Adams County Bank | |
| Adams National Bank | |
| Adams State Bank | |
| Adams State University | Colorado |
| Adams Telephone Co-Operative | Illinois |
| Adams-Land Micro Systems | Arkansas |