| AHY Management Limited | Administrative & support | 2014 |
| AI Coventry Ltd | Real estate | 2019 |
| AI Expert Systems Limited | Information & communication | 2023 |
| AI Khalifa Limited | Hospitality | 2024 |
| AI OMS Ltd | Real estate | 2023 |
| AI Worklabs Ltd | Information & communication | 2026 |
| AI4SUSTAINABILITY Limited | Professional & scientific | 2025 |
| AIB Rental Limited | Administrative & support | 2026 |
| AIB Reward & Wellbeing Ltd | Financial services | 2019 |
| AID Assist & Accomodate CIC | Hospitality | 2024 |
| Aida Alina Ltd | Other services | 2025 |
| Aida Properties Ltd | Real estate | 2026 |
| Aidinwalls Ltd | Financial services | 2023 |
| Aifs Transport Ltd | Transport & logistics | 2024 |
| Aigburth Road Developments Limited | Construction | 2016 |
| Aiken Road Happy COD Ltd | Hospitality | 2025 |
| Ailpt Fitness Ltd | Arts & recreation | 2011 |
| Ailsa Craig Nautical Services Ltd | Transport & logistics | 2023 |
| AIM (GB) Ltd | Professional & scientific | 2002 |
| AIM Professional Services Limited | Professional & scientific | 2011 |
| Aimap Ltd | Wholesale & retail | 2021 |
| Aimation Studios Ltd | Information & communication | 2024 |
| Aimed Models Limited | Information & communication | 2024 |
| Aims Business Services Ltd | Wholesale & retail | 2011 |
| Aimz Group Ltd | Professional & scientific | 2026 |
| Aindriya Marketing Solutions UK Ltd | Information & communication | 2024 |
| Ainika Limited | Information & communication | 2026 |
| Ainsley Grange Management Limited | Construction | 2024 |
| Ainss Ltd | Transport & logistics | 2026 |
| Aintelligentia Ltd | Information & communication | 2023 |
| Aion Property Investments Ltd | Real estate | 2022 |
| Air Control Engineers Limited | Administrative & support | 2006 |
| Air Freight Cargo ZIM Limited | Transport & logistics | 2019 |
| Air Galaxyuk Limited | Administrative & support | 2025 |
| Air Kraft Limited | Administrative & support | 1995 |
| Airah Holdings Limited | Real estate | 2025 |
| Airbag Disposal (UK) Limited | Water & waste | 2002 |
| Airbag Team Holdings Limited | Financial services | 2023 |
| Airbag Team Limited | Wholesale & retail | 2014 |
| Airbagsforsale (Hinckley) Limited | Professional & scientific | 2014 |
| Aircare Coventry Limited | Construction | 1999 |
| Aircooled Events Limited | Professional & scientific | 2013 |
| Airflow Solutions Ltd | Construction | 2025 |
| Airlink Holidays Limited | Administrative & support | 2008 |
| Airomatrix Technologies Ltd | Information & communication | 2024 |
| Airport Business Park Limited | Real estate | 2010 |
| Airpowerstar Ltd | Manufacturing | 2025 |
| Airwaves Group Limited | Administrative & support | 2020 |
| Airwaves Property Development Limited | Real estate | 2022 |
| Airwin Airtruth. Limited | Manufacturing | 2023 |
| Aisafe Initiative Ltd | Information & communication | 2026 |
| Aisare Limited | Wholesale & retail | 2024 |
| Aisha Essa Ltd | Other services | 2026 |
| Aisha Transport Ltd | Transport & logistics | 2024 |
| Aivar Ltd | Transport & logistics | 2021 |
| Aiyemojuba Ltd | Wholesale & retail | 2024 |
| Aizlecoed Ltd | Manufacturing | 2025 |
| AJ Amazon Ltd | Wholesale & retail | 2026 |
| AJ Care Services Ltd | Health & social care | 2021 |
| AJ Electrical & Security Services Ltd | Construction | 2018 |
| AJ Korklin Limited | Extraterritorial | 2016 |
| AJ Pro Solutions Ltd | Wholesale & retail | 2023 |
| AJ Property Care Ltd | Real estate | 2026 |
| AJ Roofing Services Ltd | Construction | 2021 |
| AJ98MM Limited | Hospitality | 2023 |
| AJA Architects Consulting Limited | Professional & scientific | 2017 |
| Ajaj Group Limited | Other services | 2024 |
| Ajanikoto London Commodities Ltd | Wholesale & retail | 2026 |
| Ajanx Ltd | Wholesale & retail | 2025 |
| Ajay Krupa Limited | Hospitality | 2007 |
| Ajaya Ltd | Wholesale & retail | 2024 |
| Ajbb Construction Limited | Construction | 2008 |
| Ajbd (Solihull) Ltd | Hospitality | 2022 |
| Ajbd Ltd | Wholesale & retail | 2013 |
| AJD Electrics Ltd | Manufacturing | 2017 |
| Ajgas Ltd | Construction | 2024 |
| Ajit Singh Investment & Properties Ltd | Real estate | 2025 |
| Ajjs Holdings Ltd | Real estate | 2025 |
| AJK (NE) Ltd | Hospitality | 2024 |
| AJK Investments & Property Limited | Real estate | 2024 |
| AJK Motors Trade Ltd | Wholesale & retail | 2023 |
| AJK Taxis Limited | Transport & logistics | 2026 |
| AJM Construction (Midlands) Ltd | Construction | 2024 |
| AJM Electrical Commercial and Industrial Ltd | Construction | 2018 |
| AJM Freight Limited | Transport & logistics | 2025 |
| Ajmultitask Ltd | Administrative & support | 2024 |
| Ajocredit Limited | Financial services | 2025 |
| Ajox Professionals Ltd | Health & social care | 2026 |
| AJP Coventry Ltd | Construction | 2020 |
| AJP Properties (COV) Ltd | Real estate | 2025 |
| AJR Builders Limited | Construction | 2025 |
| AJR Loyal Assets Ltd | Real estate | 2026 |
| AJS Estate Solutions Ltd | Real estate | 2024 |
| Ajsr Limited | Information & communication | 2024 |
| AJT Property Limited | Real estate | 2018 |
| Ajta Properties Limited | Real estate | 2020 |
| AJU Investments Limited | Financial services | 2026 |
| AJY Solutions Ltd | Professional & scientific | 2022 |
| AK Carpets Coventry Limited | Wholesale & retail | 2025 |
| AK Dreamscape Ltd | Real estate | 2026 |