| Adam Smith International |
| Addison Lee Inc. |
| Addison Lee Services Limited |
| Adidas AG |
| Admiral Group |
| Adrian's Croft |
| Advance Appliances Limited |
| Advance HE |
| Advance Training |
| Advanced Workplace Associates Ltd. |
| Advantage Creative C.I.C |
| Advent International Corporation |
| Advent International Limited |
| Advent Solutions Holdings Limited |
| Adyan Foundation |
| Aegon UK plc |
| Aeropress Inc |
| AES Limited |
| Afghanistan and Central Asian Association |
| African Digital Heritage Foundation |
| African Fashion Research Institute |
| Afrigos Film and Media Academy Ltd |
| Afro-Wren Productions |
| AG Barr plc |
| Aga Khan Foundation |