| Arif Property Services Limited | Construction | 2015 |
| Arimateia Club Ltd | Real estate | 2019 |
| Arina Doullay Ltd | Health & social care | 2025 |
| Arion Builders Limited | Construction | 2020 |
| Aris GP Limited | Health & social care | 2015 |
| Arise Accountancy Limited | Professional & scientific | 2020 |
| Arise Virtual Solutions Limited | Information & communication | 2007 |
| Arisean Reach Ltd | Professional & scientific | 2008 |
| Aristo Clothing Limited | Wholesale & retail | 2018 |
| Aristocrat Clothing Limited | Administrative & support | 2019 |
| Aristocrat LDN Ltd | Wholesale & retail | 2025 |
| Aristotle Plato Ltd | Households | 2020 |
| Aritex Limited | Professional & scientific | 2002 |
| Aritha Technologies Ltd | Information & communication | 2023 |
| Ariyel Industries Limited | Information & communication | 2026 |
| Arizona Group Ltd | Real estate | 2025 |
| ARK Alive | Arts & recreation | 2004 |
| ARK Cmcs Limited | Other services | 2021 |
| ARK Consultancy Leeds Ltd | Information & communication | 2018 |
| ARK Deliveries Ltd | Transport & logistics | 2021 |
| ARK Display Graphics Limited | Information & communication | 1997 |
| ARK Displays Ltd | Manufacturing | 2025 |
| ARK Halal Certification Authority Limited | Hospitality | 2016 |
| ARK Healthsciences Ltd | Health & social care | 2024 |
| ARK of Victory | Other services | 2010 |
| ARK Rentals Yorkshire Limited | Real estate | 2025 |
| ARK Sadaqah Jaria Limited | Wholesale & retail | 2021 |
| ARK Surgical Ltd | Health & social care | 2021 |
| ARK Venue Finder Ltd | Administrative & support | 2023 |
| Arka Techi Ltd | Information & communication | 2024 |
| Arkadiusz Mroz Ltd | Construction | 2023 |
| Arkaig Bidco Limited | Administrative & support | 2024 |
| Arkaig Holdco Limited | Administrative & support | 2024 |
| Arkaig Project Investments Limited | Administrative & support | 2024 |
| Arkan Transport Ltd | Transport & logistics | 2022 |
| Arkleboyce Architects Ltd | Professional & scientific | 2014 |
| Arkom Build Ltd | Construction | 2025 |
| Arksolinc Limited | Administrative & support | 2026 |
| Arksomes Limited | Wholesale & retail | 1976 |
| Arkwheel Limited | Professional & scientific | 2014 |
| ARL Radiology Limited | Health & social care | 2021 |
| ARL Surveys Limited | Professional & scientific | 2014 |
| Arla Foods (Westbury) Limited | Wholesale & retail | 2007 |
| Arla Foods Cheese Company Limited | Administrative & support | 2002 |
| Arla Foods Finance Limited | Manufacturing | 2005 |
| Arla Foods Hatfield Limited | Real estate | 2009 |
| Arla Foods Holdings Company Limited | Financial services | 1965 |
| Arla Foods Ingredients Felinfach Holdings Limited | Administrative & support | 2024 |
| Arla Foods Ingredients Felinfach Limited | Manufacturing | 2023 |
| Arla Foods Ingredients Felinfach Renewable Energy Limited | Energy | 2014 |
| Arla Foods Ingredients TAW Valley Limited | Manufacturing | 2010 |
| Arla Foods Ingredients UK Limited | Manufacturing | 2010 |
| Arla Foods Life Assurance Trustees Limited | Extraterritorial | 2009 |
| Arla Foods Pension Plan Trustees Limited | Extraterritorial | 1998 |
| Arla Foods UK Dairies Major Retail Limited | Professional & scientific | 1909 |
| Arla Foods UK Farmers Joint Venture Co. Limited | Wholesale & retail | 2008 |
| Arla Foods UK Investments Limited | Manufacturing | 1942 |
| Arla Foods UK PLC | Manufacturing | 1998 |
| Arla Foods UK Property Company Limited | Professional & scientific | 1949 |
| Arla Foods UK Services Ltd. | Manufacturing | 1989 |
| ARLE1 Ltd | Construction | 2021 |
| Arlington Holdings Leeds Ltd | Real estate | 2026 |
| Arln Ltd | Real estate | 2018 |
| Arlo Drainage Ltd | Water & waste | 2026 |
| Arloartex | Professional & scientific | 2017 |
| Arlotech Limited | Administrative & support | 2020 |
| ARM40 Ltd | Construction | 2023 |
| Arma Litigation Limited | Professional & scientific | 2020 |
| Armaflo Ltd | Wholesale & retail | 2015 |
| Armando Health Care Ltd | Other services | 2019 |
| Armatus Facility Management Limited | Administrative & support | 2025 |
| Armbbm Limited | Transport & logistics | 2025 |
| Armed Forces Covenant Fund Trustee Limited | Extraterritorial | 2018 |
| Armena Consulting Ltd | Information & communication | 2016 |
| Arminproperty Ltd | Real estate | 2026 |
| Armistead Engineering Services Ltd | Manufacturing | 2012 |
| Armitage Financial Solutions Limited | Financial services | 2013 |
| Armitage Housing Investments Limited | Real estate | 2024 |
| Armley Action Team CIC | Wholesale & retail | 2022 |
| Armley Beauty Lounge Limited | Other services | 2025 |
| Armley Car Clinic Limited | Wholesale & retail | 2009 |
| Armley Dent Ltd | Real estate | 2023 |
| Armley Dentist Property Limited | Real estate | 2021 |
| Armley Electrical Services Ltd | Construction | 2019 |
| Armley Enterprises Ltd | Wholesale & retail | 2013 |
| Armley European Food Limited | Wholesale & retail | 2024 |
| Armley Fones Limited | Wholesale & retail | 2020 |
| Armley Garden Centre Limited | Wholesale & retail | 2013 |
| Armley Hand Carwash Ltd | Health & social care | 2019 |
| Armley Minimarket Ltd | Wholesale & retail | 2024 |
| Armley Park Development Limited | Real estate | 2022 |
| Armley PCN Services Limited | Health & social care | 2023 |
| Armley Property Limited | Real estate | 2025 |
| Armley Ridge Road (Freehold) Ltd | Households | 2025 |
| Armley Ridge Road Convenience Store Ltd | Wholesale & retail | 2022 |
| Armley Stores Ltd | Wholesale & retail | 2026 |
| Armley Tyre Centre Limited | Wholesale & retail | 2024 |
| Armley Valeting Services Ltd | Health & social care | 2024 |
| Armley Vehicle Solutions Ltd | Professional & scientific | 2026 |
| Armo Developments Ltd | Construction | 2014 |