| APB Technik Limited | Transport & logistics | 2017 |
| Apcw Limited | Health & social care | 2022 |
| APD Controls Limited | Professional & scientific | 2023 |
| Apex Advanced Software Solutions Limited | Information & communication | 2025 |
| Apex Aitech Limited | Information & communication | 2026 |
| Apex Nitrile Ltd | Wholesale & retail | 2026 |
| Apex Professional Search Ltd | Administrative & support | 2009 |
| Apex Property Solutions (Midlands) Ltd | Other services | 2022 |
| Apex Repairs Ltd | Construction | 2023 |
| Apex Software Solutions Ltd | Information & communication | 2010 |
| APG Fitness Limited | Arts & recreation | 2016 |
| Aphus Ltd | Real estate | 2024 |
| APN Optical Services Ltd | Health & social care | 2019 |
| APN Prime Holdings Ltd | Real estate | 2024 |
| Apollo Bidco Limited | Financial services | 2019 |
| Apollo Topco Limited | Financial services | 2019 |
| Apothecare (Holdings) Limited | Real estate | 2023 |
| Apothecare Group Limited | Health & social care | 2019 |
| Appdrome Ltd | Extraterritorial | 2015 |
| Applause IT Holdings Limited | Financial services | 2026 |
| Apple Private Limited | Health & social care | 2021 |
| Apple Property Consultancy Limited | Real estate | 2013 |
| Apple Property Investments Limited | Real estate | 2015 |
| Applelodge Ltd | Administrative & support | 2009 |
| Appliancerus Ltd | Wholesale & retail | 2026 |
| Approved Distribution Limited | Wholesale & retail | 2014 |
| Approved Security Holdings Limited | Construction | 2014 |
| Approved Security Systems Limited | Construction | 2007 |
| Apptopay Ltd | Information & communication | 2018 |
| Apricitas Wellbeing Ltd | Health & social care | 2023 |
| Apricus Country Homes Ltd | Real estate | 2023 |
| APS Property Kidderminster Limited | Real estate | 2022 |
| APS Space Kidderminster Limited | Real estate | 2021 |
| Aptex Limited | Administrative & support | 2007 |
| Aptoval Limited | Real estate | 1973 |
| Aptv Limited | Manufacturing | 2003 |
| APZ Medical Ltd | Health & social care | 2024 |
| AQC Consulting Limited | Administrative & support | 2009 |
| AQC Ventures Limited | Professional & scientific | 2012 |
| Aqis Holdings Limited | Real estate | 2018 |
| AQJ Holdings Limited | Real estate | 2026 |
| Aqqz Limited | Professional & scientific | 2014 |
| AQR Limited | Transport & logistics | 2018 |
| Aqua Professional Cleaning Ltd | Administrative & support | 2022 |
| Aqua Property Development Limited | Real estate | 2025 |
| Aquasplash (Midlands) Limited | Arts & recreation | 2013 |
| Aquasport (Midlands) Limited | Arts & recreation | 2007 |
| Aquasportonline Limited | Extraterritorial | 2007 |
| Aquilis Developments Ltd | Construction | 2021 |
| Aquithm Ltd | Information & communication | 2025 |
| AR Eastern Kitchen Ltd | Hospitality | 2026 |
| AR Residential Limited | Real estate | 2008 |
| AR Solutions Private Limited | Administrative & support | 2012 |
| AR Technik Limited | Manufacturing | 2026 |
| AR Trading Group Limited | Financial services | 2024 |
| Ar&Sr Homes Limited | Real estate | 2018 |
| Ar-Av Ltd | Construction | 2017 |
| Ar-Rawda Consultancy Ltd | Information & communication | 2024 |
| Araa Group of Advocates and Legal Consultants Limited | Professional & scientific | 2025 |
| Arafatay Ltd | Wholesale & retail | 2023 |
| Arain Brotherhood Committee Ltd | Other services | 2018 |
| Arana Yang Limited | Wholesale & retail | 2026 |
| Araprint Limited | Manufacturing | 1988 |
| Aras Software, Ltd | Administrative & support | 2018 |
| Arbour Land Group Ltd | Real estate | 2025 |
| Arbury Hall Limited | Wholesale & retail | 2014 |
| Arby Investments Limited | Construction | 1942 |
| ARC Project Services Limited | Professional & scientific | 2016 |
| Arcadegame Ltd | Manufacturing | 2020 |
| Arcadian World Limited | Administrative & support | 2005 |
| Arcave Limited | Administrative & support | 2002 |
| Arcelormittal Commercial UK Ltd | Administrative & support | 1945 |
| Arch Business Consultancy and Management Services Ltd | Professional & scientific | 2019 |
| Arch Inspection Services Limited | Professional & scientific | 2008 |
| Arch Inspire Limited | Professional & scientific | 2016 |
| Archer & Peak Limited | Wholesale & retail | 2017 |
| Archer Property Group Ltd | Real estate | 2023 |
| Archer Sports Consultancy Ltd | Arts & recreation | 2022 |
| Archipelago Travel Media Ltd | Information & communication | 2025 |
| Architecture and Engineering Ltd | Construction | 2023 |
| Archsmartbusiness Holding Limited | Financial services | 2020 |
| Archway Brimstone Security Limited | Administrative & support | 2011 |
| Arcom Group Ltd | Wholesale & retail | 2026 |
| Arcus Construction Services Ltd | Construction | 2022 |
| Arden Associates Limited | Professional & scientific | 1994 |
| Arden Autos Ltd | Wholesale & retail | 2019 |
| Arden Bookkeeping Ltd | Professional & scientific | 2016 |
| Arden Business Coaching Ltd | Professional & scientific | 2015 |
| Arden Business Solutions Limited | Professional & scientific | 2013 |
| Arden Carpentry Services Limited | Construction | 2013 |
| Arden Chimney Sweeps Ltd | Administrative & support | 2022 |
| Arden Coaches Limited | Transport & logistics | 2024 |
| Arden Consulting Partners Limited | Professional & scientific | 2025 |
| Arden Court Property Ltd | Real estate | 2017 |
| Arden Dental Laboratory Limited | Health & social care | 2005 |
| Arden Developments (West Midlands) Ltd | Real estate | 2024 |
| Arden Developments Ltd. | Construction | 2015 |
| Arden Driveways & Landscaping Limited | Construction | 2020 |
| Arden Electrical Installations Ltd | Construction | 2020 |
| Arden Energy Limited | Professional & scientific | 2005 |