| Aberdeen Asset Management Ltd |
| abrdn plc (previously Standard Life Aberdeen plc) |
| Abt Associates |
| Acala Online Ltd |
| Acast AB |
| Accell Group |
| Accenture Public Limited Company |
| Access Systems (UK) Limited [ALSO: AccessPay] |
| Access Systems Inc. |
| Accidental Limited |
| ACCO Brands Corporation |
| ACDOCO |
| Acer Inc. |
| Achieve Education Limited |
| Achieve Together |
| Acorn Dairy Limited |
| Acorn Holdings B.V. (AHBV) |
| ACTED |
| Action for Hope |
| Action Global Communications |
| ActionAid Bangladesh |
| Activate the City Ltd |
| Active Communities Network |
| ADAB Festival |
| Adam Matthew Digital |