| Antler BIO (UK) Limited | Professional & scientific | 2017 |
| Antler Productions Limited | Information & communication | 2023 |
| Antobot Ltd. | Manufacturing | 2016 |
| Antomad Ltd | Professional & scientific | 2020 |
| ANTONIE@AVIATION77 Ltd | Manufacturing | 2025 |
| Antonio Craft Aviation Ltd | Manufacturing | 2025 |
| Antony Craske Ltd | Manufacturing | 2024 |
| Antwerp Dental Academy Limited | Health & social care | 2017 |
| Antwerp Dental Group Ltd | Health & social care | 2018 |
| Antwerp Property Holdings Ltd | Real estate | 2018 |
| Anvi Datta Ltd | Health & social care | 2023 |
| Anvil Court (Slough) Management Company Limited | Households | 1994 |
| Anvill (Braintree) Management Company Limited | Households | 2008 |
| ANY Solutions Limited | Information & communication | 2018 |
| Anya Housing Investments Limited | Real estate | 2024 |
| Anywhere Mobile Offices Limited | Professional & scientific | 2019 |
| Aoearth Foundation Limited | Extraterritorial | 2025 |
| Aofan TU Sheng Development Co., Ltd. | Wholesale & retail | 2026 |
| Aoscitech Ltd. | Manufacturing | 2025 |
| AOX Star Ltd | Wholesale & retail | 2025 |
| AP Architectural Projects Ltd | Professional & scientific | 2021 |
| AP Global Holdings Limited | Financial services | 2025 |
| Apandim UK Ltd | Hospitality | 2025 |
| Apartment Blinds Ltd | Manufacturing | 2024 |
| Apasphere Limited | Information & communication | 2002 |
| Apeva Holdings Ltd. | Financial services | 2018 |
| Apex Automotive Consultants Ltd | Professional & scientific | 2020 |
| Apex Brand Partners Ltd | Professional & scientific | 2025 |
| Apex Dynamics Technology Ltd | Information & communication | 2023 |
| Apex Global Commerce Limited | Mining & quarrying | 2025 |
| Apex Homes (BD) Limited | Real estate | 2025 |
| Apex Learners Ltd | Education | 2020 |
| Apex Lodge Ltd | Real estate | 2018 |
| Apex Property Inventories South East Limited | Real estate | 2017 |
| Apex Solutions Ltd | Real estate | 2016 |
| Apex Stone Ltd | Manufacturing | 2020 |
| Apexglobe Limited | Wholesale & retail | 2025 |
| Apexis Solutions Limited | Information & communication | 2025 |
| Apexops Ltd | Administrative & support | 2024 |
| Apexwell Ltd | Construction | 2026 |
| Apherion Therapeutics Limited | Professional & scientific | 2025 |
| API Sky Aviation Ltd | Manufacturing | 2023 |
| Apical Limited | Manufacturing | 1999 |
| APM Papworth Services Ltd | Professional & scientific | 2018 |
| Apobec Discovery Ltd | Manufacturing | 2018 |
| Apoidea Limited | Professional & scientific | 2019 |
| Apollo AP04 Limited | Professional & scientific | 2021 |
| Apollo AP05 Limited | Professional & scientific | 2021 |
| Apollo AP08 Limited | Professional & scientific | 2021 |
| Apollo AP09 Limited | Professional & scientific | 2021 |
| Apollo AP10 Limited | Professional & scientific | 2022 |
| Apollo AP13 Limited | Professional & scientific | 2021 |
| Apollo AP14 Limited | Professional & scientific | 2021 |
| Apollo AP20 Limited | Professional & scientific | 2021 |
| Apollo AP21 Limited | Professional & scientific | 2021 |
| Apollo AP23 Limited | Professional & scientific | 2021 |
| Apollo AP24 Limited | Professional & scientific | 2021 |
| Apollo AP25 Limited | Professional & scientific | 2021 |
| Apollo AP28 Limited | Professional & scientific | 2022 |
| Apollo AP30 Limited | Professional & scientific | 2021 |
| Apollo AP31 Limited | Professional & scientific | 2022 |
| Apollo AP32 Limited | Professional & scientific | 2022 |
| Apollo AP33 Limited | Professional & scientific | 2022 |
| Apollo AP36 Limited | Professional & scientific | 2022 |
| Apollo AP37 Limited | Professional & scientific | 2023 |
| Apollo AP39 Limited | Professional & scientific | 2022 |
| Apollo AP40 Limited | Professional & scientific | 2024 |
| Apollo AP42 Limited | Professional & scientific | 2026 |
| Apollo AP43 Limited | Professional & scientific | 2022 |
| Apollo AP45 Limited | Professional & scientific | 2023 |
| Apollo AP46 Limited | Professional & scientific | 2023 |
| Apollo AP47 Limited | Professional & scientific | 2024 |
| Apollo AP48 Limited | Professional & scientific | 2024 |
| Apollo AP49 Limited | Professional & scientific | 2024 |
| Apollo AP50 Limited | Professional & scientific | 2024 |
| Apollo AP51 Limited | Professional & scientific | 2024 |
| Apollo AP52 Limited | Professional & scientific | 2024 |
| Apollo AP53 Limited | Professional & scientific | 2024 |
| Apollo AP57 Limited | Professional & scientific | 2026 |
| Apollo Therapeutics Enterprise Limited | Financial services | 2021 |
| Apollo Therapeutics Group Limited | Financial services | 2021 |
| Apollo Therapeutics Limited | Financial services | 2021 |
| Apollo Therapeutics NO.2 LLP | | 2015 |
| Apollos Church Advisory Limited | Professional & scientific | 2024 |
| Apomar Construct Ltd | Construction | 2020 |
| Apomar Trans Ltd | Transport & logistics | 2022 |
| Apostolic Faith Mission of Africa - Cambridge Limited | Other services | 2015 |
| Apothecare ME Ltd | Other services | 2023 |
| App Developer Studio Limited | Information & communication | 2021 |
| App Holdings Limited | Professional & scientific | 2007 |
| App Probuild Ltd | Construction | 2020 |
| Appchocolate Ltd | Information & communication | 2014 |
| Appdone Limited | Information & communication | 2026 |
| Apple Blossoms Childcare Limited | Health & social care | 2020 |
| Apple Spice Events Limited | Administrative & support | 2007 |
| Apple Technical Recruitment (UK) Limited | Administrative & support | 2014 |
| Apple Tree Court Residents Association Ltd | Households | 2013 |
| Applecourt (Freehold) Limited | Households | 2000 |
| Appleton Cambridge Ltd | Real estate | 2026 |
| Appleton Gate Management Company Limited | Households | 2007 |