| Aico Aquatic Products Co., Ltd. | Agriculture & fishing | 2019 |
| Aida Trading Co., Ltd | Extraterritorial | 2022 |
| Aidan Construction Ltd | Construction | 2016 |
| Aide Xier (China) Import & Export Trade Ltd | Extraterritorial | 2024 |
| Aiden Property Management Ltd | Real estate | 2022 |
| Aidi Home Group Co., Ltd | Manufacturing | 2023 |
| Aike Trading Limited | Wholesale & retail | 2021 |
| Aile Industrial Automation Co., Ltd | Extraterritorial | 2019 |
| Aile Medical Technology Limited | Extraterritorial | 2021 |
| Ailis Consultancy Ltd | Information & communication | 2015 |
| Ailis Technology Ltd | Extraterritorial | 2025 |
| Ailoyed Ltd | Manufacturing | 2024 |
| Aily Trade Co., Limited | Wholesale & retail | 2023 |
| Aimo Auto Technology Ltd | Manufacturing | 2022 |
| Aimrise Industrial Co., Ltd | Wholesale & retail | 2025 |
| Aingaran (UK) LLP | | 2015 |
| Aironex Ltd | Energy | 2021 |
| Aisimo Corporation Co., Ltd | Extraterritorial | 2013 |
| Aiyize Limited | Extraterritorial | 2023 |
| AJ Birney Services Limited | Professional & scientific | 2013 |
| AJ Knitting Co., Ltd | Extraterritorial | 2018 |
| AJ Reubens Solicitors Limited | Professional & scientific | 2018 |
| Aj's Luxury Elite Ltd | Administrative & support | 2026 |
| AJG Imaging Limited | Wholesale & retail | 2008 |
| Ajnb Properties Limited | Real estate | 2015 |
| AJR Consultancy Limited | Professional & scientific | 2012 |
| AJR Electrical (London) Ltd | Construction | 2013 |
| AJR Refurbishment and Decorations Limited | Construction | 2012 |
| AJT Analytics Ltd | Professional & scientific | 2014 |
| AK Corp Ltd | Wholesale & retail | 2022 |
| AK Future Consultancy Limited | Information & communication | 2014 |
| AKA Films Limited | Information & communication | 2020 |
| Akay Clockhouse Limited | Hospitality | 2023 |
| AKG Biofueltech Co., Ltd. | Professional & scientific | 2011 |
| Akher Limited | Real estate | 2024 |
| Akrylics Limited | Other services | 2025 |
| Akstay Property Ltd | Real estate | 2021 |
| Akstex (XYH) Industrial Limited | Extraterritorial | 2017 |
| AL & ME Ltd | Wholesale & retail | 2024 |
| AL Bridge Cultural Academy Limited | Wholesale & retail | 2024 |
| Aladdin’S Cave Fine Food Limited | Wholesale & retail | 2023 |
| Alamby Fashion Limited | Extraterritorial | 2020 |
| Alan Bicycle Parts Co., Ltd. | Wholesale & retail | 2023 |
| Alandale Group of Companies Limited | Extraterritorial | 2008 |
| Alandale Holdings Limited | Construction | 1996 |
| Alandale Limited | Extraterritorial | 2008 |
| Alandale Logistics (Northern) Limited | Professional & scientific | 2010 |
| Alandale Logistics Limited | Construction | 1996 |
| Alandale Plant & Scaffolding Limited | Construction | 2002 |
| Alandale Scaffolding Group Limited | Administrative & support | 1992 |
| Alandale Scaffolding Services Limited | Construction | 2021 |
| Alarmwise Limited | Administrative & support | 2023 |
| Alastair Cars Limited | Wholesale & retail | 2011 |
| ALB Engineering Services Limited | Construction | 2017 |
| Alba Home Vision Limited | Information & communication | 2008 |
| Albemarle Guest Houses Limited | | 1962 |
| Albemarle Park (21 to 37) Ltd | Households | 2005 |
| Albion Drive Limited | Real estate | 2012 |
| Albionne Future Technology Research Academy (UK) Co., Ltd. | Manufacturing | 2025 |
| Albm London Limited | Wholesale & retail | 2023 |
| Albol Properties Ltd | Real estate | 2019 |
| Alder Advice Limited | Professional & scientific | 2011 |
| Alder-Diels (UK) Ltd | Extraterritorial | 2016 |
| Alderton Hill Developments Limited | Construction | 2026 |
| Aldi Plumbing and Heating Ltd | Construction | 2026 |
| Aldous & Stamp Limited | Financial services | 1968 |
| Aldous and Stamp (Services) Limited | Manufacturing | 1967 |
| Aleksandra Herrera-Sokolowska Limited | Health & social care | 2022 |
| Alertsensor Tech Ltd | Manufacturing | 2025 |
| Alety Homecare UK Intl Trade Co., Ltd | Wholesale & retail | 2022 |
| Alexia Stam Limited | Extraterritorial | 2018 |
| Alfa Medics Limited | Health & social care | 2009 |
| Alfred Mews Management Company Limited | Households | 1989 |
| Alibegova Co., Limited | Energy | 2025 |
| Alice O'Grady Limited | Health & social care | 2024 |
| Aliev Group Limited | Construction | 2024 |
| Alifante International Communication Co., Ltd | Extraterritorial | 2016 |
| Aline Digital Ltd | Information & communication | 2013 |
| Aliou Limited | Extraterritorial | 2020 |
| Alisidun Thermal Energy Co., Ltd | Manufacturing | 2022 |
| Alison Phillips Architectural Design Limited | Professional & scientific | 2018 |
| Alissa Food (UK) Co., Ltd | Manufacturing | 2024 |
| Aljanoob Trade Co., Limited | Manufacturing | 2021 |
| ALL About Wine Limited | Wholesale & retail | 2014 |
| ALL in (Tianjin) Ship Service Co., Ltd | Manufacturing | 2025 |
| ALL YOU Travel Service Limited | Administrative & support | 2023 |
| Allbest Global Tranese Cooperation Ltd | Professional & scientific | 2013 |
| Allfine International Co., Ltd. | Manufacturing | 2013 |
| Allison Electronics Co., Ltd. | Extraterritorial | 2015 |
| Alloya Biotechnology Co., Ltd | Extraterritorial | 2012 |
| Allpromo Limited | Manufacturing | 2026 |
| Allrains Group Company Limited | Extraterritorial | 2014 |
| Allroad Supply Chain Management Co., Ltd | Extraterritorial | 2016 |
| Allzones Aviation Ltd | Transport & logistics | 2025 |
| Allzones Limited | Administrative & support | 1974 |
| Almagic Co., Ltd | Wholesale & retail | 2020 |
| Almas Khanum Ltd | Health & social care | 2016 |
| Almers Limited | Administrative & support | 2015 |
| Almutewkl Co., Ltd | Wholesale & retail | 2020 |
| Aloysius London Limited | Real estate | 2024 |