| Anthony Osborne Surveyors Ltd | Professional & scientific | 2017 |
| Anthony's Studio Limited | Professional & scientific | 2007 |
| Anthropocene Actions C.I.C. | Other services | 2017 |
| Anti Pesto Limited | Extraterritorial | 2001 |
| Antichi Decori Ltd | Wholesale & retail | 2021 |
| Anticipate Ltd | Professional & scientific | 2007 |
| Antifragile Studios Ltd | Information & communication | 2023 |
| Antifragile Systems Limited | Professional & scientific | 2019 |
| Antillion Ltd | Information & communication | 2011 |
| Antillion Parent Ltd | Information & communication | 2011 |
| Antini Properties Limited | Real estate | 2022 |
| Antique Doors & Fireplaces Limited | Wholesale & retail | 2025 |
| Antivibe (Hull) Limited | Extraterritorial | 1997 |
| Antjam Limited | Real estate | 2018 |
| Anton Invicta Ltd | Arts & recreation | 2023 |
| Antoniasdeli Ltd | Hospitality | 2021 |
| Antoniasdelicatering Ltd | Hospitality | 2025 |
| Antoninus Limited | Other services | 2012 |
| Antonio Florio Collectables Ltd | Wholesale & retail | 2025 |
| Antony Hooper Ltd | Professional & scientific | 2016 |
| Antony Katrina Associates Limited | Professional & scientific | 2019 |
| Antrim House Freehold Limited | Real estate | 2010 |
| Antwis Collaborative Ltd | Education | 2024 |
| ANU Internet Services Limited | Information & communication | 2005 |
| Anushans Ltd | Wholesale & retail | 2024 |
| Anvari Design Limited | Professional & scientific | 2014 |
| Anwar Supermarket Ltd | Wholesale & retail | 2019 |
| Anxhela’S Car Wash Ltd | Other services | 2019 |
| ANY Aggregates Ltd | Wholesale & retail | 2024 |
| ANY Excuse Ltd | Wholesale & retail | 2025 |
| ANY Place ANY Time Ltd | Information & communication | 2024 |
| Anya’S Apparel Ltd | Wholesale & retail | 2024 |
| Anybodyyoga CIC | Arts & recreation | 2026 |
| Anything BUT Standard Group Limited | Professional & scientific | 2013 |
| Anything Essential Ltd | Wholesale & retail | 2024 |
| ANZ Agri Crop Sciences Limited | Wholesale & retail | 2022 |
| ANZ B&F Consultancy Limited | Professional & scientific | 2020 |
| ANZ Properties Limited | Real estate | 2022 |
| AO Aladeojebi Limited | Health & social care | 2024 |
| AO Build Ltd | Construction | 2024 |
| AO Consultancy Ltd | Professional & scientific | 2026 |
| AO Dynamics Ltd | Information & communication | 2019 |
| AO Hire and Consultancy Limited | Professional & scientific | 2026 |
| Aobib Holdings Limited | Real estate | 2022 |
| AOD Electrical Limited | Construction | 2025 |
| Aoko Ltd | Other services | 2023 |
| AOL Services Ltd | Real estate | 2015 |
| AON2 Ltd. | Manufacturing | 2015 |
| Aone Children's Services Ltd | Health & social care | 2022 |
| Aone Furniture Traders Ltd | Wholesale & retail | 2022 |
| Aone Healthcare Services Ltd | Health & social care | 2023 |
| Aone Realty Ltd | Real estate | 2024 |
| Aora Pilates Ltd | Arts & recreation | 2025 |
| Aoura Limited | Professional & scientific | 2007 |
| AOV Group Ltd | Professional & scientific | 2021 |
| AP Building Services Bristol Ltd | Construction | 2012 |
| AP Carlson Ltd | Extraterritorial | 2023 |
| AP Design Services Limited | Construction | 2009 |
| AP Electrical Group Ltd | Construction | 2026 |
| AP First AID Training Ltd | Health & social care | 2016 |
| AP Midas Limited | Professional & scientific | 2009 |
| AP SD Eighty Four Limited | Wholesale & retail | 2026 |
| AP SD Eighty Limited | Wholesale & retail | 2025 |
| AP SD Eighty Three Limited | Wholesale & retail | 2026 |
| AP SD Forty Five Limited | Wholesale & retail | 2025 |
| AP SD Seventy One Limited | Wholesale & retail | 2025 |
| AP SD Twenty Limited | Wholesale & retail | 2025 |
| AP Webb Limited | Construction | 2011 |
| AP Wood Limited | Construction | 2017 |
| APA Capital Investments Ltd | Professional & scientific | 2022 |
| Apaaro Ltd | Professional & scientific | 2019 |
| Apache IX Limited | Information & communication | 2014 |
| Apache IX Trustees Limited | Professional & scientific | 2024 |
| Apak Group Limited | Information & communication | 1979 |
| Aparthotel Cannon Street Limited | Real estate | 2014 |
| Aparthotel CW Limited | Financial services | 2019 |
| Aparthotel Investments II Limited | Financial services | 2019 |
| Aparthotel Investments Limited | Extraterritorial | 2018 |
| Aparthotel Kensington Limited | Administrative & support | 2006 |
| Aparthotel Leasing Limited | Financial services | 2018 |
| Aparthotel West London Holdings Limited | Financial services | 2021 |
| APB International (Safety Services) Limited | Administrative & support | 2013 |
| APB Services (South West) Limited | Construction | 2002 |
| APC Property Management Ltd | Real estate | 2018 |
| Apcc Future Ltd | Manufacturing | 2020 |
| Apdg Limited | Information & communication | 2022 |
| Apds Limited | Wholesale & retail | 2003 |
| Apeirogon Group Limited | Real estate | 2018 |
| Apella Technologies Limited | Information & communication | 2025 |
| Apept Ltd | Information & communication | 2020 |
| Apero Games Ltd | Information & communication | 2017 |
| Aperture Search Ltd | Administrative & support | 2026 |
| Apew and Scotford MOT & Repairs Limited | Extraterritorial | 2006 |
| Apex Bristol Property Services Ltd | Construction | 2024 |
| Apex Building Bristol Ltd | Construction | 2019 |
| Apex Building Plastics (South West) Ltd | Wholesale & retail | 2002 |
| Apex Carpentry & Build Ltd | Manufacturing | 2022 |
| Apex Clothing Direct Ltd | Wholesale & retail | 2026 |
| Apex Construction Administration Ltd | Construction | 2018 |
| Apex Construction Holdings Ltd | Construction | 2023 |