| Assertis Limited | Information & communication | 2000 |
| Asset Pest Control Services LLP | | 2012 |
| Associate Commissioning Ltd | Construction | 2003 |
| Associated Building Company Ltd | Construction | 2020 |
| Assouline Equine Services Limited | Wholesale & retail | 2002 |
| Assured Driveways Kent Limited | Construction | 2024 |
| Assured Roofing Kent Limited | Construction | 2024 |
| Assured Scaffolding Limited | Construction | 2017 |
| Assured Service Reliability Limited | Administrative & support | 2015 |
| Assured Solutions Property Ltd | Real estate | 2019 |
| Assured Solutions Services Limited | Information & communication | 2015 |
| Astm International UK | Public administration | 2021 |
| Aston Property Lettings Ltd | Real estate | 2020 |
| Astor Media Limited | Information & communication | 2022 |
| Astra Park (Gillingham) Management Company Limited | Real estate | 2010 |
| Astraen Ltd | Wholesale & retail | 2025 |
| Astral Homes Limited | Real estate | 2018 |
| Astria Capital Limited | Professional & scientific | 2022 |
| Astria Metals Ltd | Construction | 2022 |
| Astro Technical Services Ltd | Public administration | 2023 |
| Astrology Center Limited | Education | 2025 |
| Astute Financial Management UK Limited | Financial services | 2017 |
| Astute Platform Services Limited | Financial services | 2016 |
| AT Construct Limited | Construction | 2023 |
| AT Curate Limited | Professional & scientific | 2023 |
| AT Grab Limited | Transport & logistics | 2025 |
| AT Group Investments Limited | Financial services | 2023 |
| AT Mechanical Limited | Construction | 2023 |
| AT Select International Limited | Administrative & support | 2010 |
| AT Transport Ltd | Transport & logistics | 2023 |
| ATA Global Ltd | Wholesale & retail | 2019 |
| Atac Developments Limited | Administrative & support | 2014 |
| Atac Solutions Limited | Administrative & support | 2007 |
| Ataraxia 10 Limited | Financial services | 2021 |
| Ataraxia 11 Limited | Financial services | 2021 |
| Ataraxia 12 Limited | Financial services | 2021 |
| Ataraxia 13 Limited | Financial services | 2022 |
| Ataraxia 14 Limited | Financial services | 2022 |
| Ataraxia 15 Limited | Financial services | 2022 |
| Ataraxia 16 Limited | Financial services | 2023 |
| Ataraxia 17 Limited | Financial services | 2023 |
| Ataraxia 18 Limited | Financial services | 2023 |
| Ataraxia 4 Ltd | Financial services | 2019 |
| Ataraxia 5 Limited | Financial services | 2019 |
| Ataraxia 6 Ltd | Financial services | 2019 |
| Ataraxia 7 Limited | Financial services | 2021 |
| Ataraxia 8 Limited | Financial services | 2021 |
| Ataraxia 9 Limited | Financial services | 2021 |
| Ataraxia Broking Ltd | Financial services | 2010 |
| Ataraxia Dixons Ltd | Financial services | 2018 |
| ATF Installations 2017 Limited | Construction | 2017 |
| ATG Bidco Limited | Administrative & support | 2021 |
| ATG Global Limited | Administrative & support | 2021 |
| ATG Midco 2 Limited | Professional & scientific | 2021 |
| ATG Midco Limited | Professional & scientific | 2021 |
| Athena Control Limited | Extraterritorial | 2022 |
| Athshe Ltd | Information & communication | 2016 |
| Athwal Properties (Kent) Limited | Real estate | 2026 |
| Atikem Services Limited | Administrative & support | 2021 |
| Atkins Enterprises Limited | Professional & scientific | 2023 |
| Atkinson & West Ltd | Construction | 2024 |
| Atkotron Ltd | Arts & recreation | 2019 |
| Atlantis Kent 2 Ltd | Hospitality | 2025 |
| Atlanytics Ltd. | Administrative & support | 2018 |
| Atlas Recruitment Group Limited | Administrative & support | 2015 |
| Atley Financial Services Ltd | Financial services | 2025 |
| ATM Ventures PVT Ltd | Wholesale & retail | 2022 |
| ATMP4S Ltd | Real estate | 2025 |
| ATO Catering Ltd | Hospitality | 2017 |
| Atoll Mill Ltd | Real estate | 2025 |
| Atoll Software Applications Consultancy Ltd | Administrative & support | 2016 |
| Atom Carpentry Limited | Construction | 2022 |
| Atom Juice Estates Limited | Real estate | 2019 |
| Atom Juice Limited | Information & communication | 2007 |
| Atom Juice SHC Holdings Limited | Financial services | 2024 |
| ATP Engineering Ltd | Construction | 2020 |
| ATR Capital Ltd | Extraterritorial | 2023 |
| ATS Automation Ltd | Professional & scientific | 2012 |
| ATS Group Members Ltd | Financial services | 2019 |
| ATS Mouldings Ltd | Manufacturing | 1979 |
| ATS Packaging Ltd | Administrative & support | 2024 |
| ATS Property Company Ltd | Real estate | 2018 |
| Attwood Stevens Projects Limited | Professional & scientific | 2015 |
| Audhd Consulting Ltd | Education | 2025 |
| Audio Stream Limited | Wholesale & retail | 2012 |
| Audio Visual Expert Ltd | Construction | 2021 |
| Audiosweets Group Limited | Information & communication | 2012 |
| Audiosweets Limited | Information & communication | 2014 |
| Audrika and Co Limited | Public administration | 2023 |
| Auga Ltd | Health & social care | 2022 |
| August Lion Consulting Ltd | Information & communication | 2023 |
| August Lion Ltd | Professional & scientific | 2017 |
| Augustinnistor Ltd | Transport & logistics | 2024 |
| Aura Building Services Ltd | Construction | 2014 |
| Aura Construction Limited | Administrative & support | 2009 |
| Aura FX Trading Limited | Financial services | 2026 |
| Aurelis International Ltd. | Financial services | 2020 |
| Aurelius Law Limited | Professional & scientific | 2025 |
| Auren Labs Ltd | Wholesale & retail | 2026 |
| Aurora BG Ltd | Hospitality | 2018 |