| A&B Property Management Ltd | Administrative & support | 2018 |
| A&C Universe Ltd | Wholesale & retail | 2020 |
| A&Clocks Ltd | Other services | 2018 |
| A&D Carpenter's Limited | Construction | 2019 |
| A&I Locals Ltd | Wholesale & retail | 2024 |
| A&S Market II Ltd | Wholesale & retail | 2020 |
| A&S Sloniatko (EU) Ltd | Hospitality | 2018 |
| A-Side Official Limited | Extraterritorial | 2023 |
| A. Nice (Holdings) Limited | Financial services | 1992 |
| A.A. Pensions Trustees Limited | Extraterritorial | 2013 |
| A.E.Groves Limited | Real estate | 1961 |
| A.J Master Builders Ltd | Construction | 2019 |
| A.J. Land and Property Limited | Real estate | 2026 |
| A.Monger Limited | Construction | 1953 |
| A.R.C Groundworks Ltd | Construction | 2017 |
| A.S. Pressure Engineering Limited | Manufacturing | 2001 |
| A1 Bathrooms and Kitchens Limited | Construction | 2013 |
| A1 Bathrooms Limited | Extraterritorial | 2013 |
| A1 Delta Taxis BSK Ltd | Transport & logistics | 2026 |
| A1 Kitchens Limited | Extraterritorial | 2015 |
| A10 Consultancy Ltd | Professional & scientific | 2019 |
| A101 Ltd | Construction | 2025 |
| A1CODE Ltd. | Information & communication | 2013 |
| A2M Property Limited | Real estate | 2019 |
| A4 Metal Recycling Limited | Water & waste | 2006 |
| A4 Skip Hire Limited | Water & waste | 2014 |
| A4 Snack Bar Ltd | Hospitality | 2025 |
| AA Acquisition Co Limited | Professional & scientific | 2004 |
| AA Brand Management Limited | Professional & scientific | 2013 |
| AA Corporation Limited | Professional & scientific | 1999 |
| AA Financial Services Limited | Financial services | 1967 |
| AA Insurance Holdings Limited | Professional & scientific | 2015 |
| AA Intermediate Co Limited | Professional & scientific | 2004 |
| AA Limited | Financial services | 2004 |
| AA Media Limited | Information & communication | 2007 |
| AA MID Co Limited | Professional & scientific | 2004 |
| AA RV Limited | Extraterritorial | 2010 |
| AA Senior Co Limited | Professional & scientific | 2005 |
| AA Technical Solutions Limited | Financial services | 2014 |
| AA Urban Properties Limited | Real estate | 2023 |
| AA Venture LAB Limited | Administrative & support | 2018 |
| AAA X Holdings Limited | Financial services | 2026 |
| Aaas E-Commerce Ltd | Wholesale & retail | 2026 |
| Aannav Private Limited | Information & communication | 2025 |
| Aarp Abodes Ltd | Real estate | 2025 |
| Aarp Co-Living Ltd | Real estate | 2025 |
| Aarp Homes Ltd | Real estate | 2019 |
| Aarp Technologies Ltd | Information & communication | 2019 |
| AAT Property Maintenance Ltd | Construction | 2024 |
| Aavcm Ltd | Real estate | 2021 |
| AB Design Studio Ltd | Professional & scientific | 2023 |
| AB Holmes Property Ltd | Real estate | 2016 |
| AB Tiling LLP | | 2015 |
| Abacus Employment Services Limited | Administrative & support | 1991 |
| Abacus Event Catering Ltd | Hospitality | 2014 |
| Abacus Logistics (Felixstowe) Ltd | Transport & logistics | 2017 |
| Abacus Logistics Ltd | Transport & logistics | 2004 |
| ABC Learning Limited | Health & social care | 2018 |
| ABC Tennis Ltd | Arts & recreation | 2012 |
| ABC Tilija Realty Ltd | Real estate | 2025 |
| ABC Transport Services Limited | Transport & logistics | 2019 |
| ABH Dwellings Ltd | Real estate | 2024 |
| Abiha Consulting Ltd | Information & communication | 2012 |
| Abingdon Commercial Services Ltd | Real estate | 2026 |
| ABJ Professional Services Ltd | Transport & logistics | 2025 |
| Ablerent Limited | Households | 1989 |
| About Events Limited | Administrative & support | 2016 |
| About Face Solutions Limited | Information & communication | 1991 |
| Above Limited | Administrative & support | 2009 |
| Above the Oceans Limited | Transport & logistics | 2020 |
| Abridge International Ltd | Wholesale & retail | 2018 |
| Absolute Accountax Ltd. | Professional & scientific | 2015 |
| Absolute Consulting Limited | Professional & scientific | 2023 |
| Absolute Diversity Limited | Professional & scientific | 2024 |
| Absolutely Anywhere Limited | Wholesale & retail | 2025 |
| AC Claims Consultants Ltd | Financial services | 2015 |
| AC Kingston Ltd | Real estate | 2022 |
| ACA Health Ltd | Professional & scientific | 2026 |
| Academy of Aesthetic Medicine Limited | Health & social care | 2018 |
| Acanthus Limited | Other services | 2018 |
| Acap Cleaning Services Ltd | Administrative & support | 2010 |
| Acap Home Stays Ltd | Real estate | 2026 |
| ACC PVT Ltd | Transport & logistics | 2016 |
| Accalia Ltd | Professional & scientific | 2014 |
| Accelero Tech Ltd | Information & communication | 2023 |
| Accent Relocation Limited | Other services | 2012 |
| Accentria Consulting Ltd | Information & communication | 2023 |
| Accentria Ltd | Information & communication | 2018 |
| Access IT Recruitment Ltd | Administrative & support | 2018 |
| Accessipool Basingstoke Ltd | Other services | 2026 |
| Accident Assistance Services Limited | Administrative & support | 2016 |
| Accolade Properties LLP | | 2019 |
| Accolade Property Group Ltd | Professional & scientific | 2025 |
| Accolade Stays Limited | Real estate | 2023 |
| Accomore Consultants Ltd | Professional & scientific | 2023 |
| Accord Dental Services Ltd | Health & social care | 2024 |
| Accountability Business Services Ltd | Information & communication | 2014 |
| Accountability Group Holdings Ltd | Financial services | 2024 |
| Accountability Services Ltd | Professional & scientific | 2022 |
| Accountancy and Taxation Services Limited | Professional & scientific | 1996 |