- American Foundation for Donation and Transplantation
- American Inns of Court
- American Institute of Aeronautics and Astronautics
- American Medical Student Association
- American Medical Women's Association
- American Moving and Storage Association
- American Peanut Council
- American Physical Therapy Association
- American Registry for Internet Numbers
- American Security Group
- American Society for Clinical Pharmacology and Therapeutics
- American Society for Therapeutic Radiology and Oncology
- American Society of Consultant Pharmacists
- American Society of Pension Professionals and Actuaries
- American Society of Transplant Surgeons
- American Statistical Association
- American Subcontractors Association
- American Water Resources Association
- AMK Drives and Controls Inc.
- AMU
- Anaheim Orange County Visitors Bureau
- Andrews
- Animal Welfare League of Alexandria
- Anthem-Trigon Blue Cross Blue Shield
- Apex Environmental Inc.
- Apex Systems Inc.
- APICS
- Apogen Technologies
- Aquent
- Arby's
- Arc3 Gases
- Archer Bailey Gay Lodge #275
- Architects Dayton Thompson and Associates
- Arkios Biodevelopment International
- Arlandria Floors
- Arlington Convention and Visitors Service
- Arlington County
- Armstrong Enterprise Communications
- Artie's
- ASAP Fast
- ASIS International
- Asset Strategy Consultants
- Association for Career and Technical Education
- Association for Education and Rehabilitation of the Blind and Visually Impaired
- Association For Enterprise Integration
- Association for the Advancement of Medical Instrumentation
- Association Management Group
- Association of Air Medical Service
- Association of Clinical Research Professionals
- Association of Fundraising Professionals