| AR Project Group Ltd | Construction | 2026 |
| AR Rihla Ltd | Wholesale & retail | 2017 |
| Ar-Razzaq Real Estate Limited | Construction | 2024 |
| ARA AI Consultancy Ltd | Information & communication | 2025 |
| ARA Flooring Ltd | Construction | 2023 |
| ARA Prestige Living Ltd | Real estate | 2026 |
| ARA Property Holdings Ltd | Real estate | 2025 |
| ARA Restaurant Ltd | Hospitality | 2019 |
| Arabuild Property Investments Ltd | Real estate | 2023 |
| Araco Ltd | Financial services | 2022 |
| Arafah Property Investment Ltd | Real estate | 2026 |
| Aram International Food Centre Ltd | Wholesale & retail | 2023 |
| ARB Finance Limited | Extraterritorial | 2023 |
| Arber Building Contracts Ltd | Construction | 2015 |
| Arbitrage Talent Ltd | Administrative & support | 2026 |
| Arblease Limited | Financial services | 2021 |
| Arbney Construction Ltd | Construction | 2012 |
| Arbon Property Consultancy Limited | Other services | 2011 |
| Arbor Verification Tech Ltd | Information & communication | 2023 |
| Arbours Electrical Limited | Construction | 2018 |
| Arbury House Management Company Limited | Households | 2012 |
| ARC Care (Northants) Ltd | Health & social care | 2025 |
| ARC Compliance Group Ltd | Professional & scientific | 2026 |
| ARC Construction (Northampton) Ltd | Construction | 2015 |
| ARC Gymnastics Ltd | Education | 2019 |
| ARC Interior Furnishings Ltd | Wholesale & retail | 2019 |
| ARC Rural Consultancy Limited | Professional & scientific | 2025 |
| ARC UK G Ltd | Wholesale & retail | 2021 |
| ARC Warehouse Solutions Limited | Professional & scientific | 2023 |
| Arcade Growth Ltd | Wholesale & retail | 2023 |
| Arcadian Garden Features Limited | Extraterritorial | 1999 |
| Arcana Events UK Ltd | Hospitality | 2021 |
| Arcane Protection Ltd | Financial services | 2018 |
| Arcde Ltd | Professional & scientific | 2024 |
| Arch Consultancy & Build Ltd | Construction | 2026 |
| Arch MAE Ltd | Real estate | 2024 |
| Archalign Orthodontics Ltd | Health & social care | 2024 |
| Archer Estates Limited | Wholesale & retail | 1992 |
| Archihouse Ltd. | Construction | 2014 |
| Archios Consultants Ltd | Construction | 2022 |
| Architectural & Planning Ltd | Professional & scientific | 2010 |
| Archway (Manchester) Limited | Health & social care | 2013 |
| Archways Real Estate Limited | Real estate | 2020 |
| Arcorbis Design Limited | Professional & scientific | 2015 |
| Arctec Systems Limited | Information & communication | 2016 |
| Arcteck Designs Limited | Professional & scientific | 2003 |
| Arctic Express Global Ltd | Transport & logistics | 2015 |
| Arcyka Trans Ltd | Transport & logistics | 2023 |
| Ardchattan Manse Plants Ltd | Education | 2010 |
| Ardent Financing Group Limited | Professional & scientific | 2003 |
| Ardent Masters Ltd | Construction | 2025 |
| Ardian Transport Ltd | Transport & logistics | 2021 |
| Ardington Construction Management Limited | Construction | 2021 |
| Ardington House Living Ltd | Health & social care | 2023 |
| Ardot Ltd | Health & social care | 2019 |
| Area Property Ltd | Real estate | 2019 |
| Aren Enterprises Ltd | Hospitality | 2024 |
| Ares House of Beauty Ltd | Other services | 2025 |
| Ares Sports Ltd | Wholesale & retail | 2023 |
| Arete Enterprise Ltd | Professional & scientific | 2025 |
| Argent Financial Services Limited | Financial services | 1992 |
| Argentum Limited | Manufacturing | 1992 |
| Argon Movers and Storage Ltd | Administrative & support | 2012 |
| Arhivi Limited | Financial services | 2014 |
| Aria Aras Ltd | Wholesale & retail | 2018 |
| Aria Independent Living Limited | Health & social care | 2025 |
| Ariana Online Limited | Wholesale & retail | 2016 |
| Ariane Healthcare Solutions Limited | Health & social care | 2021 |
| Ariba Power Solutions Limited | Wholesale & retail | 2012 |
| Ariba Powercare Limited | Administrative & support | 2010 |
| Ariba Resources Ltd | Administrative & support | 1999 |
| Arif Ahmed Limited | Professional & scientific | 2015 |
| Ariggio Ltd | Professional & scientific | 2026 |
| Aris Logistics Ltd | Transport & logistics | 2024 |
| Aris Management Group Limited | Real estate | 2021 |
| Arise Education Limited | Education | 2019 |
| Arisehire Ltd | Information & communication | 2024 |
| Ariva Limited | Information & communication | 2022 |
| Arivogue Group Limited | Wholesale & retail | 2026 |
| Ariyen Properties Limited | Real estate | 2018 |
| Arizi Italian Restaurant Ltd | Hospitality | 2023 |
| Arizona Homes Limited | Real estate | 2023 |
| ARJ Healthcare Ltd | Health & social care | 2024 |
| ARK AGE Intelligent Retail Ltd | Wholesale & retail | 2026 |
| ARK Commercial Consulting Ltd | Professional & scientific | 2013 |
| ARK Extension Services Ltd | Construction | 2022 |
| ARK Organs Limited | Manufacturing | 2015 |
| ARK Pharma Graphics Limited | Manufacturing | 2002 |
| ARK Plumbing & Heating Limited | Construction | 2014 |
| ARK Properties Group Limited | Real estate | 2016 |
| ARK Property Portfolio Limited | Households | 2024 |
| ARK Voicing Limited | Wholesale & retail | 2015 |
| Arkeb Properties Ltd | Real estate | 2025 |
| Arkin Construction Ltd | Construction | 2026 |
| Arkitez Ltd | Professional & scientific | 2021 |
| Arks Apartments UK Limited | Hospitality | 2020 |
| Arks Budget Apartments Limited | Hospitality | 2020 |
| Arlene Sophia Michelle Swaby Ltd | Extraterritorial | 2025 |
| Arlet-Invest Ltd | Transport & logistics | 2018 |
| Arlington Property Services Limited | Real estate | 2016 |