| Araya Malee Property Limited | Real estate | 2024 |
| ARB Convenience Ltd | Wholesale & retail | 2026 |
| ARB Covers Ltd | Wholesale & retail | 2021 |
| ARB Drylining Ltd | Construction | 2021 |
| ARB International Group Ltd | Wholesale & retail | 2021 |
| ARB Vans Ltd | Administrative & support | 2025 |
| Arbb Properties Ltd | Real estate | 2017 |
| Arben Ltd | Construction | 2018 |
| Arbha Tech Ltd | Information & communication | 2018 |
| Arbiter Data Ltd | Information & communication | 2020 |
| Arbor Court Residents Association Limited | Households | 1993 |
| Arbor Vitae Artwork Ltd | Wholesale & retail | 2025 |
| Arboretum and City Limited | Real estate | 2000 |
| Arbormark Ltd | Agriculture & fishing | 2012 |
| Arbz Healthcare Ltd | Health & social care | 2026 |
| Arbz Holdings Company Ltd | Health & social care | 2026 |
| ARC Assessment Ltd | Professional & scientific | 2026 |
| ARC Care Services Ltd | Health & social care | 2025 |
| ARC Digital Safeguarding Limited | Information & communication | 2019 |
| ARC Events Organisation Ltd | Administrative & support | 2026 |
| ARC Exams Ltd | Education | 2015 |
| ARC Infinity Group Limited | Financial services | 2026 |
| ARC Realty Ltd | Real estate | 2025 |
| ARC Screen Print Limited | Manufacturing | 1991 |
| ARC Tiling Limited | Construction | 2013 |
| ARC Welding Services Limited | Manufacturing | 2003 |
| Arc-Therapy Ltd | Health & social care | 2025 |
| ARC2 Group Limited | Professional & scientific | 2016 |
| Arca Health Limited | Health & social care | 2016 |
| Arca Investment Consultancy Ltd | Other services | 2022 |
| Arca Living Holdings Ltd | Financial services | 2021 |
| Arca Living Ltd | Wholesale & retail | 2014 |
| Arcade Exhibition Design Limited | Administrative & support | 2002 |
| Arcade Galleria Ltd | Wholesale & retail | 2025 |
| Arcade Gallery Limited | Arts & recreation | 2017 |
| Arcade Mania Global Limited | Manufacturing | 2019 |
| Arcadia Agencies Ltd | Real estate | 2000 |
| Arcadia Cleaning Ltd | Administrative & support | 2023 |
| Arcadia Gloabl Ltd | Other services | 2024 |
| Arcadia Housing Ltd | Real estate | 2023 |
| Arcadia Innovation Ltd | Manufacturing | 2023 |
| Arcadia Kitchens & Bathrooms Ltd | Other services | 2016 |
| Arcadian Aparthotel Limited | Hospitality | 2021 |
| Arcadian Bakery Limited | Real estate | 2018 |
| Arcadian City Limited | Hospitality | 2025 |
| Arcadian EOT Trustee Limited | Professional & scientific | 2023 |
| Arcadian Financial Services Ltd | Professional & scientific | 2025 |
| Arcadian Industries Ltd | Manufacturing | 2018 |
| Arcadian Leisure 2 Ltd | Hospitality | 2020 |
| Arcadian Leisure Ltd | Hospitality | 2020 |
| Arcadian Management Limited | Administrative & support | 2024 |
| Arcadian Noodle Bar Limited | Hospitality | 2024 |
| Arcadian Products (2000) Limited | Professional & scientific | 1999 |
| Arcadian Tasty Foods Ltd | Wholesale & retail | 2026 |
| Arcan Vale Tech Ltd | Wholesale & retail | 2025 |
| Arcanum Design Solutions Limited | Professional & scientific | 2002 |
| Arcelormittal Tailored Blanks Birmingham Limited | Manufacturing | 1997 |
| Arch & MIA Ltd | Wholesale & retail | 2025 |
| Arch B Ltd | Real estate | 2025 |
| Arch Define UK Limited | Other services | 2024 |
| Arch Energy Business Investments Ltd | Other services | 2024 |
| Arch Squared Investments Limited | Real estate | 2019 |
| Arch Tools Ltd | Manufacturing | 2020 |
| Arch UK Property Ltd | Hospitality | 2019 |
| Archaeomuse Academy Ltd | Education | 2019 |
| Archer Bassett Ltd | Real estate | 2013 |
| Archer Locksmith and Security Ltd | Administrative & support | 2024 |
| Archer Trading Limited | Wholesale & retail | 2026 |
| Archers Club Ltd | Wholesale & retail | 2024 |
| Archfit Beauty by Rabia Ehsan Ltd | Other services | 2022 |
| Archfit Limited | Other services | 2014 |
| Archi-Tekt Partnership Limited | Professional & scientific | 2006 |
| Archidocture Lane Ltd | Construction | 2023 |
| Archie Steel Limited | Real estate | 2024 |
| Archistry Limited | Professional & scientific | 2025 |
| Architectural Building Fabrications Ltd | Manufacturing | 2014 |
| Architectural Co-Operative Ltd | Professional & scientific | 2010 |
| Architectural Louvre Products and Services Limited | Construction | 1999 |
| Architecture and Interior Design Ltd | Professional & scientific | 2017 |
| Archive IT Storage & Logistics Ltd | Transport & logistics | 2022 |
| Archside Corner Properties Limited | Real estate | 2025 |
| Archway Coaching Ltd | Professional & scientific | 2024 |
| Archway Housing Services Ltd | Hospitality | 2024 |
| Arché Housing Group C.I.C. | Hospitality | 2025 |
| Arck Limited Liability Partnership | | 2006 |
| Arclane Limited | Real estate | 2021 |
| Arclo Design & Build Limited | Construction | 2025 |
| Arcmotion Limited | Professional & scientific | 2019 |
| Arco Pipework Systems Limited | Manufacturing | 2006 |
| Arcol Design Limited | Manufacturing | 2006 |
| Arcomm Limited | Professional & scientific | 2024 |
| Arcon Architects Ltd | Professional & scientific | 2010 |
| Arcon Care Services Limited | Health & social care | 2024 |
| Arconic Closure Systems International (UK) Limited | Manufacturing | 1959 |
| Arconic Manufacturing (GB) Limited | Manufacturing | 1959 |
| Arconic UK Finance | Professional & scientific | 2000 |
| Arconic UK Holdings Limited | Professional & scientific | 2000 |
| Arcr Limited | Professional & scientific | 2025 |
| Arcs Store Limited | Wholesale & retail | 2025 |
| Arctek Ltd | Professional & scientific | 2019 |