| Applight Limited | Professional & scientific | 2020 |
| Appointree Limited | Professional & scientific | 2012 |
| Appointscheme Ltd | Transport & logistics | 2019 |
| Apposite Knowledge Development and Training Ltd | Administrative & support | 2017 |
| Appreciate U C.I.C. | Health & social care | 2014 |
| Apprentice-Link Ltd | Administrative & support | 2024 |
| Approved Electrical Midlands Certification Ltd | Construction | 2021 |
| Approved Electrical Midlands Ltd | Construction | 2018 |
| Approved Haulage Ltd | Transport & logistics | 2023 |
| Approved Parcel Delivery Ltd | Extraterritorial | 2023 |
| Approved Roofs Ltd | Construction | 2025 |
| Appstrata Ltd | Information & communication | 2026 |
| Appvibe Ltd | Wholesale & retail | 2024 |
| Appzlab Limited | Information & communication | 2025 |
| Aprod Limited | Financial services | 2024 |
| Apropos Bridal Limited | Wholesale & retail | 2025 |
| APS Digital Limited | Information & communication | 2016 |
| APS GAS Services Limited | Energy | 2025 |
| APS Luxury Travel Limited | Transport & logistics | 2008 |
| Aptisens Ltd | Manufacturing | 2014 |
| Aptly Group Ltd | Construction | 2026 |
| AQL EMC Limited | Professional & scientific | 1988 |
| Aqsa Minimarket Limited | Wholesale & retail | 2025 |
| Aqua BLU Aesthetics Ltd | Extraterritorial | 2022 |
| Aqua Cleaning Service (Worcs) Limited | Administrative & support | 2025 |
| Aqua Descaling Co. Limited | Arts & recreation | 1982 |
| Aqua Force Special Waste Limited | Water & waste | 1997 |
| Aqua Magic Ltd | Wholesale & retail | 2022 |
| Aqua Media (UK) Ltd | Wholesale & retail | 2009 |
| Aqua Regia Ltd | Water & waste | 2022 |
| Aqua U.K. Electrical Limited | Construction | 2008 |
| Aqua-Plumb Installations Ltd. | Construction | 2022 |
| Aquacivil Solutions Limited | Construction | 2025 |
| Aquatech Environmental Services Limited | Water & waste | 1999 |
| AR Building Investments Ltd | Real estate | 2024 |
| AR Commerce Limited | Wholesale & retail | 2026 |
| AR Estate Lettings Limited | Real estate | 2026 |
| AR Midlands Autos Ltd | Wholesale & retail | 2025 |
| AR Outlet Ltd | Administrative & support | 2025 |
| AR Plumbing & Building Ltd | Construction | 2020 |
| AR Plumbing & Heating Bath Ltd | Construction | 2022 |
| AR Real Estate Limited | Real estate | 2021 |
| Arabant Group Limited | Transport & logistics | 2012 |
| Arabesque International Limited | Professional & scientific | 2024 |
| Arabian Estates Limited | Real estate | 2023 |
| Arabian Moonlight Ltd | Wholesale & retail | 2025 |
| Arabian Vibes Ltd | Professional & scientific | 2026 |
| Arachna Ltd | Information & communication | 2005 |
| Aradex Limited | Health & social care | 2022 |
| Aradhiya Limited | Public administration | 2020 |
| Aragon Care Limited | Health & social care | 2019 |
| Aramar Limited | Professional & scientific | 1986 |
| Aran Freightway Ltd | Transport & logistics | 2025 |
| Aran Transport Ltd | Transport & logistics | 2017 |
| Arav Transport Ltd | Transport & logistics | 2025 |
| ARB Assets Managment Ltd | Real estate | 2024 |
| ARB Building Services Ltd | Construction | 2011 |
| ARB Groundworks Ltd | Construction | 2023 |
| Arbiply Ltd | Information & communication | 2026 |
| Arbiter Growth Limited | Wholesale & retail | 2024 |
| Arbor Life Limited | Health & social care | 2024 |
| Arbour Lodge Limited | Financial services | 1998 |
| Arbourmount Investment Limited | Real estate | 2024 |
| ARC Electrical Testing Limited | Construction | 2022 |
| ARC Electrical UK Services Limited | Manufacturing | 2021 |
| Arcadian Assets Limited | Construction | 2003 |
| Arcadian Development Residential Limited | Other services | 2017 |
| Arcadian Developments Limited | Construction | 2003 |
| Arcadian Devp Residential Limited | Wholesale & retail | 2024 |
| Arcadian Retail Ltd | Wholesale & retail | 2018 |
| Arcare (West Midlands) Limited | Professional & scientific | 2000 |
| Arcare Boscobel Holdings Limited | Health & social care | 2017 |
| Arcare Boscobel House Limited | Financial services | 2017 |
| Arcare Camber Holdings Limited | Financial services | 2019 |
| Arcare Camber Lodge Limited | Health & social care | 2019 |
| Arcare Codsall Holdings Limited | Financial services | 2024 |
| Arcare Codsall House Limited | Health & social care | 2025 |
| Arcare Edge Hall Limited | Health & social care | 2010 |
| Arcare for Forte Limited | Health & social care | 2013 |
| Arcare Homes Limited | Extraterritorial | 2012 |
| Arcare Orton Holdings Limited | Financial services | 2023 |
| Arcare Orton Meadows Limited | Extraterritorial | 2012 |
| Arcare Residential Care Limited | Health & social care | 2007 |
| Arcare Stourcliffe Limited | Real estate | 2021 |
| Arcare Wanderers Limited | Health & social care | 2010 |
| Arcare Woodlands Limited | Health & social care | 2010 |
| Arch Doors and Windows Supply Ltd | Manufacturing | 2024 |
| Arch Doors&Windows Limited | Manufacturing | 2022 |
| Archi Estimations Ltd | Wholesale & retail | 2025 |
| Archimoulds Studio Ltd | Professional & scientific | 2025 |
| Archway Ventures Ltd | Wholesale & retail | 2024 |
| Arcix Ltd | Financial services | 2025 |
| Arctic Care Ltd | Other services | 2023 |
| Arcturus Consulting Ltd | Information & communication | 2007 |
| ARD Lifestyle Ltd | Extraterritorial | 2025 |
| Ardaas Construction Ltd | Construction | 2025 |
| Ardel OEM Limited | Wholesale & retail | 2012 |
| Arden Healthcare Ltd | Health & social care | 2024 |
| Arden Manor Care Limited | Real estate | 2014 |
| Ardenfit Limited | Other services | 2019 |