- Ace Charitable Foundation
- ACE INA Foundation
- Actavis US
- Acuity Brands, Inc.
- Acumen International
- Acuson Corp. Computed Sonography
- Acxiom Corporation
- Ada County Association of Realtors
- ADA-ES, Inc.
- Adaptec Inc.
- ADC Foundation
- ADC Telecommunications, Inc.
- Adelante Capital Management, LLC
- ADM Archer-Daniels Midland
- Administaff, Inc.
- Adobe Systems, Inc.
- ADP Automatic Data Processing, Inc.
- Advanced Cardiovascular Systems, Inc.
- Advanced Fibre Communications
- Advanced Micro Devices