| Anbe Property Limited | Real estate | 2019 |
| Andean Solutions Ltd | Professional & scientific | 2018 |
| Anderton Aero Limited | Manufacturing | 2019 |
| Andoug Property Maintenance Limited | Construction | 2023 |
| Andrew Bareham Limited | Professional & scientific | 2006 |
| Andrew Dixon and Co Holdings Limited | Financial services | 2020 |
| Andrew Dixon Estate Agents Limited | Real estate | 1987 |
| Andrew Donald Groundworks Ltd | Construction | 2020 |
| Andrew Mason Consultancy Limited | Professional & scientific | 2015 |
| Andrews-Whalley Consulting Ltd | Professional & scientific | 2023 |
| Andrzej Opach Ltd | Construction | 2012 |
| Andurs Ltd | Other services | 2020 |
| Andy Kendrick Ltd | Information & communication | 2019 |
| Andz Ltd | Transport & logistics | 2025 |
| Angel Assets Limited | Health & social care | 2019 |
| Angels Without Wings Limited | Health & social care | 2010 |
| Angie Kirby Limited | Professional & scientific | 2025 |
| Anglerfish Interiors Ltd | Manufacturing | 2023 |
| Anglesey Developments Limited | Real estate | 2018 |
| Anglesey Homes Assets Limited | Real estate | 2019 |
| Anglesey Homes Ltd | Real estate | 2018 |
| Anglesey Hotel Developments Ltd | Construction | 2023 |
| Anglesey Hotel Lease MGT Ltd | Real estate | 2024 |
| Angus Valeting Ltd | Administrative & support | 2025 |
| Anguyo's Psychiatric Care Limited | Health & social care | 2014 |
| Angy European Food Ltd | Wholesale & retail | 2023 |
| ANH Automotive Ltd | Wholesale & retail | 2023 |
| Animal Data Centre Limited | Information & communication | 1992 |
| Ankobra Mansions Limited | Construction | 2012 |
| Annabel Church Limited | Real estate | 2013 |
| Anne Clifft Education Limited | Education | 2015 |
| Another Property Development Limited | Construction | 2017 |
| Another Property Management Ltd | Real estate | 2018 |
| Another World Comics and Toys Ltd | Wholesale & retail | 2026 |
| Anpal Ltd | Manufacturing | 2004 |
| ANQ Tower Ltd | Real estate | 2023 |
| Antalya Magic Cuts Ltd | Other services | 2022 |
| Anten Ltd | Other services | 2020 |
| Antenar Ltd | Other services | 2019 |
| Antequa Ltd | Other services | 2020 |
| Anwar & Co Consulting Ltd | Information & communication | 2025 |
| Anytime Hire Ltd | Administrative & support | 2024 |
| Aouval Ltd | Administrative & support | 2020 |
| AOV Trade Solutions Ltd | Wholesale & retail | 2026 |
| AP Cleans Ltd | Administrative & support | 2025 |
| AP Commercial GAS Ltd | Construction | 2025 |
| AP Davies Ltd | Wholesale & retail | 2023 |
| AP Kingsley Properties Ltd | Real estate | 2025 |
| AP Motor Works Ltd | Wholesale & retail | 2025 |
| Apac Foods Ltd | Manufacturing | 2025 |
| Apalisok Capital Ltd | Health & social care | 2019 |
| Apartments in Ibiza International Limited | Administrative & support | 2016 |
| Apartments in Ibiza UK Limited | Hospitality | 2016 |
| APD 88 Ltd | Hospitality | 2012 |
| APD Capital Ltd | Construction | 2026 |
| Apex Accountants Limited | Professional & scientific | 2011 |
| Apex Fabs Limited | Manufacturing | 2014 |
| Apex Heating & Plumbing (Midlands) Ltd | Construction | 2026 |
| Apex Linvar Limited | Manufacturing | 2010 |
| Apex Space Solutions Limited | Manufacturing | 2010 |
| Apex Water Care Ltd | Construction | 2018 |
| Apex-Link Enterprise Ltd | Extraterritorial | 2026 |
| Apexmartt Ltd | Wholesale & retail | 2023 |
| Aphe Ltd | Construction | 2018 |
| Apley Castle Construction Ltd | Manufacturing | 2009 |
| Apley Chemicals Limited | Wholesale & retail | 2018 |
| Apley Freight Services Ltd | Transport & logistics | 2019 |
| Apley Group Limited | Wholesale & retail | 2020 |
| Apley Medical Ltd | Health & social care | 2015 |
| Apley Property Limited | Real estate | 2023 |
| Apley UK Limited | Professional & scientific | 2021 |
| Apmv Ltd | Real estate | 2013 |
| Apoblu Ltd | Other services | 2019 |
| Apollo Sport Injury and Health Ltd | Other services | 2017 |
| Apollo Sport Wellness Ltd | Other services | 2017 |
| Apothecary Solutions Ltd | Professional & scientific | 2018 |
| App Central UK Ltd | Information & communication | 2018 |
| APPLE8MAN Limited | Health & social care | 2023 |
| Appleyard Grove Limited | Real estate | 2004 |
| Appliance Repair Experts Ltd | Other services | 2025 |
| Applick Ltd | Information & communication | 2022 |
| Applied Leasing Ltd | Financial services | 1990 |
| Applied Sleep Limited | Health & social care | 2021 |
| Approved Energy Limited | Construction | 2021 |
| Aqua Red Ltd | Other services | 2018 |
| Aquablast Systems Limited | Manufacturing | 2008 |
| Aquadale Farm Management Limited | Real estate | 2025 |
| Aquaflame Plumbing & Heating Limited | Construction | 2005 |
| Aquaforce (Concrete Services) Limited | Construction | 2010 |
| Aquaguard Pumps Ltd | Manufacturing | 2021 |
| Aquasoft Systems Limited | Water & waste | 2013 |
| Aquastart Limited | Arts & recreation | 1985 |
| Aquaswift Limited | Water & waste | 2005 |
| Aqueduct After Hours Club Ltd | Education | 2023 |
| AQUILA21 Limited | Information & communication | 2017 |
| AR Oral Surgery Services Limited | Real estate | 2025 |
| AR Properties and Housing Ltd | Real estate | 2021 |
| ARA Electrical Services Ltd | Construction | 2023 |
| ARA Global Ltd | Administrative & support | 2016 |
| Aramesh Properties Ltd | Real estate | 2022 |