- 360Solutions Group
- AARP
- AdvaMed
- Advisory Board
- AFGE Local 3721
- AFLAC Associate
- African-American Women's Clergy Association
- Africare
- Afro-American Historical and Genealogical Society
- Albertine Enterprises
- Allfirst Bank
- Alliance for Organ Donation and Transplantation
- Alliance for Telecommunications Industry Solutions ATIS)
- Alliance of Automobile Manufacturers
- America's Blood Centers
- America's Community Bankers
- American Bankers Association
- American Bar Association
- American Benefits Council
- American Chemical Society
- American College of Preventive Medicine
- American Council of Life Insurers
- American Council of the Blind
- American Council on Education
- American Federation of Labor and Congress of Industrial Organizations AFL-CIO)
- American Federation of Teachers Program on Retirement and Retirees AFT)
- American Financial Services Association
- American Gas Association
- American Health Care Association
- American Health Quality Association
- American Hospital Association
- American Immigration Lawyers Association
- American Institute of Architects - DC
- American Medical Rehabilitation P. Association
- American Nursery Landscape Association
- American Nurses Credentialing Center
- American Petroleum Institute
- American Pharmaceutical Association
- American Public Human Services Association
- American Society of Association Executives
- American Society of Nephrology
- American Society of Pediatric Nephrology
- American Sportscaster
- American Wind Energy Association
- Aon
- Aptify
- Armed Forces Retirement Home - Washington
- Ascension Health
- Ashland, Inc.
- Associated Luxury Hotels