| Arts & Crafts Bedrooms Limited | Manufacturing | 2017 |
| Arts & Crafts Installation Limited | Manufacturing | 2012 |
| Arts & Crafts Kitchens Limited | Manufacturing | 2015 |
| Arts & Crafts Ltd. | Wholesale & retail | 2008 |
| Arts & Crafts Renovations Limited | Manufacturing | 2025 |
| Arts Intelligence Limited | Administrative & support | 1997 |
| Arts Marketing Association | Other services | 1993 |
| Arts Online Bournemouth Limited | Education | 2021 |
| Arts Professional Media Ltd | Information & communication | 2020 |
| Aruocco Ltd | Professional & scientific | 2023 |
| Arvass Group Ltd | Real estate | 2025 |
| Arya Ayaz Ltd | Hospitality | 2019 |
| Arya Global Consultancy Limited | Administrative & support | 2020 |
| Arya Kartal Ltd | Hospitality | 2022 |
| AS Fire & Rescue Equipment Limited | Manufacturing | 2003 |
| AS One Media Ltd | Professional & scientific | 2019 |
| AS Path Ltd | Health & social care | 2019 |
| ASA Ventilation Ltd | Construction | 2023 |
| ASA1987 Ltd | Manufacturing | 2026 |
| Asad Logistics Ltd | Transport & logistics | 2025 |
| Asad Systems Ltd | Construction | 2026 |
| Asas Trade Ltd | Wholesale & retail | 2025 |
| Asase Innovation Studio Ltd | Professional & scientific | 2026 |
| ASC Associates Limited | Professional & scientific | 2015 |
| Ascend Australia Education Ltd | Education | 2026 |
| Ascend QA Limited | Professional & scientific | 2013 |
| Ascendal Aviation Limited | Professional & scientific | 2026 |
| Ascendant Media Ltd | Information & communication | 2026 |
| Ascendia Consultant Group Ltd | Information & communication | 2025 |
| Ascentia Foodservice Equipment Limited | Manufacturing | 2015 |
| Ascham Road Management Limited | Households | 2017 |
| Ascs Consulting Limited | Professional & scientific | 2026 |
| ASE International Ltd | Financial services | 2019 |
| Asempa Limited | Information & communication | 2006 |
| Asent Labs Ltd | Information & communication | 2023 |
| Aseptuva Ltd | Manufacturing | 2022 |
| Asfi Awards Ltd | Administrative & support | 2017 |
| Asgard Design & Build Ltd | Construction | 2023 |
| ASH Croft Veterinary Practice LLP | | 2022 |
| ASH Croft Vets Ltd | Professional & scientific | 2025 |
| ASH Elements Events Limited | Arts & recreation | 2024 |
| ASH Tree House Investments Ltd | Financial services | 2024 |
| Asha Legacy Group Ltd | Professional & scientific | 2023 |
| Ashburton Grove (Holbeach) Management Company Ltd | Households | 2019 |
| Ashcroft Gardens Property Management Company Limited | Real estate | 2005 |
| Ashcroftbtl Limited | Real estate | 2022 |
| Ashdale Mobile Home Park Ltd. | Hospitality | 2023 |
| Ashdon Childrens Nursery Ltd | Education | 2013 |
| Ashdon Inns Limited | Hospitality | 2021 |
| Ashfield Gardens (Isleham) Management Company Limited | Households | 2022 |
| Ashlar (ST. Crispins) Management Company Limited | Households | 2009 |
| Ashley (Newmarket) Management Company Limited | Households | 2023 |
| Ashley Apartments (Freehold) Limited | Real estate | 2011 |
| Ashley Apartments Management Company Limited | Households | 2009 |
| Ashley Courtney Riba Aabc Limited | Professional & scientific | 2020 |
| Ashlynn Limited | Health & social care | 2020 |
| Ashmere Cardiology Limited | Health & social care | 2025 |
| Ashmount Forge Limited | Agriculture & fishing | 2007 |
| Ashmount Property Developments Limited | Construction | 2018 |
| Ashmount Residential Limited | Real estate | 2023 |
| Ashtead Court Property Management Company Limited | Administrative & support | 2002 |
| Ashwell & Nesbit Limited | Wholesale & retail | 2000 |
| Ashwell Maltings Management Limited | Households | 1990 |
| Ashwick Resources Limited | Information & communication | 2008 |
| Ashwoodcmc Ltd | Professional & scientific | 2020 |
| Ashworth Park Management Company Limited | Households | 1988 |
| Ashworth Photography Limited | Professional & scientific | 2008 |
| Asia Pacific Chemicals Co., Ltd | Extraterritorial | 2011 |
| Asia Secret Recipes Ltd | Other services | 2019 |
| Asialeo Co., Ltd | Wholesale & retail | 2020 |
| Asian Cuisine Holdings Group Limited | Wholesale & retail | 2026 |
| Asiautos Ltd | Agriculture & fishing | 2024 |
| Asice Limited | Information & communication | 2015 |
| Asija Ltd | Information & communication | 2026 |
| ASJ Online Ltd | Information & communication | 2016 |
| ASK IT Solutions Ltd | Information & communication | 2016 |
| ASK Media Ltd | Financial services | 2025 |
| ASK Scientific Ltd | Professional & scientific | 2013 |
| ASK Sean Ltd | Administrative & support | 2014 |
| Ask's Residential Ltd | Real estate | 2025 |
| Askomil Limited | Information & communication | 2023 |
| Aslam Surgical Consultancy Limited | Professional & scientific | 2015 |
| Aslan Fast-Food Ltd | Hospitality | 2023 |
| Asmeh Europe Industries Limited | Mining & quarrying | 2025 |
| Asmore UK Technology Limited | Wholesale & retail | 2024 |
| Asomx Technology Co., Ltd | Extraterritorial | 2018 |
| Aspect Innovations Ltd | Information & communication | 2010 |
| Aspect Property Management Holdings Ltd | Financial services | 2016 |
| Aspect Property Management Limited | Administrative & support | 2005 |
| Aspect Safety Mirrors Limited | Wholesale & retail | 2009 |
| Aspects Building and Maintenance Limited | Construction | 2018 |
| Aspects Building Contractors Limited | Construction | 2001 |
| Asphalt Group Limited | Financial services | 2018 |
| Aspinalls (Willingham) Management Limited | Households | 2017 |
| Aspiralane Ltd | Information & communication | 2025 |
| Aspire Biosciences Limited | Professional & scientific | 2022 |
| Aspire Electrical Solutions Ltd | Construction | 2014 |
| Aspire Plus Limited | Health & social care | 2020 |
| Aspire Renovation Ltd | Construction | 2025 |
| Aspires Consultants Ltd | Professional & scientific | 2025 |