| Andlis Investments Ltd | Real estate | 2021 |
| Andon Property Limited | Real estate | 2022 |
| Andrew Cole Estate Agents Limited | Real estate | 2015 |
| Andrew Muir Decorative Arts and Design Ltd | Wholesale & retail | 2010 |
| Andrew Rowdon Travel Limited | Administrative & support | 2009 |
| Andy Chadwick Limited | Professional & scientific | 2021 |
| Andy Phillips Intel and Insight Limited | Professional & scientific | 2025 |
| Andyfreight Holdings Limited | Professional & scientific | 2003 |
| Andyfreight Investments Limited | Real estate | 2025 |
| Andyfreight Limited | Transport & logistics | 1987 |
| Andypack Wholesale Limited | Wholesale & retail | 2008 |
| Anglo-Estonian Limited | Administrative & support | 2024 |
| Angus Electrical Contractors Ltd | Administrative & support | 2017 |
| ANN Vowles Family Law Ltd | Professional & scientific | 2021 |
| Anna's House Childminding Ltd | Health & social care | 2026 |
| Annette Hollis Health and Wellbeing Ltd | Health & social care | 2023 |
| Annie's Farm Events Limited | Agriculture & fishing | 2004 |
| Anson Bernard Ltd | Administrative & support | 2014 |
| Anto Sofie Serv Ltd | Transport & logistics | 2026 |
| AP Vehicle Transport Ltd | Wholesale & retail | 2021 |
| AP30 Investments Ltd | Real estate | 2018 |
| Apex Taxi Ltd | Transport & logistics | 2025 |
| Apexis Housing Solutions Ltd | Hospitality | 2025 |
| APK Smart Repair Limited | Wholesale & retail | 2025 |
| Apodd Foundation | Professional & scientific | 2012 |
| Apollo Furnaces Limited | Professional & scientific | 2009 |
| Apollo Hotel Management Limited | Administrative & support | 2017 |
| Apperley PHS Limited | Other services | 2017 |
| Approach Community Homes Limited | Financial services | 2010 |
| Approved Sealants Midlands Limited | Construction | 2018 |
| Aquarius Heating & Plumbing Services Limited | Construction | 2005 |
| Aquatax Limited | Professional & scientific | 2007 |
| Aquila Home Improvements Ltd | Construction | 2022 |
| AR Ventures Ltd | Real estate | 2018 |
| ARB Central Ltd | Agriculture & fishing | 2026 |
| Arbil Limited | Manufacturing | 1978 |
| Arbor Solutions Ltd | Wholesale & retail | 2013 |
| ARC Media (Midlands) Limited | Information & communication | 2012 |
| Arcade News Limited | Wholesale & retail | 2016 |
| Arcal Developments Limited | Construction | 2003 |
| Architectural Stainless Interiors Limited | Manufacturing | 2003 |
| Arden Park Care Limited | Health & social care | 1999 |
| ARI Property Investment Ltd | Real estate | 2024 |
| Aries Infotech Limited | Information & communication | 2009 |
| Aristocraft Kitchens & Bedrooms Ltd | Wholesale & retail | 2012 |
| Arkline Developments Ltd | Construction | 2025 |
| Arkstone Ever True Group Ltd | Financial services | 2026 |
| Arktmj Ltd | Real estate | 2025 |
| ARL Couriers Ltd | Transport & logistics | 2012 |
| Armack Chemicals Limited | Manufacturing | 1975 |
| Armatone Systems Limited | Professional & scientific | 2015 |
| Armortag Ltd | Manufacturing | 2023 |
| Armour Lift Limited | Extraterritorial | 2022 |
| Armstrong Chase Accounting Limited | Professional & scientific | 2016 |
| Armstrong Chase Limited | Other services | 2021 |
| Arrow Building Maintenance Limited | Construction | 2024 |
| Arrow Solar Solutions Limited | Extraterritorial | 2024 |
| Artemes Waste Solutions Ltd. | Water & waste | 2013 |
| Artificial Elegance Ltd | Wholesale & retail | 2022 |
| Artificial Grass West Midlands Ltd | Administrative & support | 2022 |
| Artison Forklifts Ltd | Extraterritorial | 2006 |
| Arts Audience Insights CIC | Professional & scientific | 2021 |
| Arundale Properties Limited | Households | 2015 |
| ASA Surfacing Ltd | Construction | 2025 |
| ASB Electrics Limited | Construction | 2025 |
| Ascentiar PLC | Professional & scientific | 2015 |
| Ashby Auto Finance Ltd | Financial services | 2017 |
| Ashcrofts Accountants Limited | Professional & scientific | 2021 |
| Ashford Refrigeration Services Ltd | Energy | 2000 |
| Ashtree Property Solutions Ltd | Real estate | 2018 |
| Ashwood Technical Services Limited | Professional & scientific | 2003 |
| Askdrew Ltd | Households | 2026 |
| Askonnect Solutions Limited | Information & communication | 2026 |
| Aspen Technology Ltd | Information & communication | 1998 |
| Aspire Global Network EOT Limited | Administrative & support | 2023 |
| Aspire Global Network Limited | Administrative & support | 1999 |
| Aspire Painting Contractors Limited | Construction | 2017 |
| Asprey Properties Limited | Real estate | 2016 |
| ASR Wholesale Ltd | Wholesale & retail | 2025 |
| ASS Food Services Ltd | Hospitality | 2025 |
| Assets Loft London Ltd | Financial services | 2022 |
| Assets Loft Ltd | Professional & scientific | 2018 |
| Associated Industrial Machinery Services Limited | Transport & logistics | 2001 |
| Assure Electrical Limited | Construction | 2025 |
| Assure Security (WM) Limited | Administrative & support | 2014 |
| Astbury Development Co (West Midlands) Ltd | Construction | 2024 |
| Astley Partnership Limited | Professional & scientific | 2011 |
| Aston Vasey LLP | | 2004 |
| Astraea Therapy Services Ltd | Health & social care | 2020 |
| Astro Property Maintenance Limited | Construction | 2022 |
| AT Digital People Limited | Information & communication | 2017 |
| AT HCW Ltd | Administrative & support | 2025 |
| Atek Services Ltd | Other services | 2017 |
| Atelier Designs (UK) Limited | Extraterritorial | 1994 |
| ATG Packing Solutions Ltd | Administrative & support | 2024 |
| Athena Fiduciaries Limited | Financial services | 2014 |
| Athena Fiduciary Management Limited | Financial services | 2018 |
| Athlete Impact Ltd | Education | 2025 |
| Atlantic Shopping Limited | Information & communication | 2013 |
| Atlas Distribution Group Ltd | Transport & logistics | 2026 |