| Arden Business Centre (Bredbury) Limited | Real estate | 1989 |
| Arden Dies Limited | Manufacturing | 1965 |
| Arden Engraving Limited | Manufacturing | 1999 |
| Arden Enterprises Group LLP | | 2025 |
| Arden Hall Storage Limited | Transport & logistics | 2018 |
| Arden Software Limited | Information & communication | 1955 |
| Ardenic Ltd | Professional & scientific | 2025 |
| Ardent Endeavours Ltd | Financial services | 2020 |
| Ardent Fire Services Ltd | Public administration | 2026 |
| ARE They Legit Ltd | Information & communication | 2026 |
| Arete Consultancy Limited | Professional & scientific | 2015 |
| Arfa Enterprises Ltd | Wholesale & retail | 2012 |
| Arfa Properties Ltd | Real estate | 2025 |
| Argent Properties LLP | | 2012 |
| Argonville Holding Ltd | Administrative & support | 2015 |
| Argonville Media Limited | Administrative & support | 2008 |
| Argus Research & Analytics Ltd | Wholesale & retail | 2025 |
| Argyle Formwork Ltd | Construction | 2020 |
| Argyll Inheritance & Estate Limited | Professional & scientific | 2019 |
| ARH Automotive Ltd | Wholesale & retail | 2023 |
| Aria Construction Limited | Real estate | 2019 |
| Arian Enterprise Ltd | Wholesale & retail | 2024 |
| Arianafatimaservices UK Ltd | Wholesale & retail | 2021 |
| Arif Ashraf Limited | Professional & scientific | 2016 |
| Arikara Limited | Transport & logistics | 2025 |
| Aris Electrical Ltd | Construction | 2020 |
| Aris Properties (NW) Ltd | Real estate | 2023 |
| Ariwood Properties Limited | Real estate | 2015 |
| Arjo Machines Limited | Administrative & support | 2008 |
| ARK Carpentry Services Ltd | Manufacturing | 2026 |
| ARK Construction (UK) Ltd | Construction | 2006 |
| ARK Insolvency Ltd | Financial services | 2022 |
| ARK People Ltd | Administrative & support | 2024 |
| Arkell Homes Ltd | Real estate | 2024 |
| Arkell Properties Limited | Real estate | 2022 |
| Arkenstone Limited | Construction | 2003 |
| Arkitektkontoret Arne Hoffmann Mnal Ltd | Administrative & support | 2008 |
| Arks Nextdoor Ltd | Real estate | 2020 |
| ARL Motor Company Limited | Wholesale & retail | 2021 |
| Arlanfor Holdings Limited | Hospitality | 2019 |
| Arlen Cyber Protection Limited | Information & communication | 2024 |
| Arletheo Design Limited | Wholesale & retail | 2023 |
| Arlo Accountancy Limited | Professional & scientific | 2017 |
| Arlo Swain Estates Ltd | Real estate | 2018 |
| ARM Courier Limited | Transport & logistics | 2025 |
| ARM Transport Ltd | Transport & logistics | 2014 |
| Armaan Takeaway Limited | Hospitality | 2022 |
| Armaco Limited | Administrative & support | 2012 |
| Armchair Acquisitions (Property) Ltd | Real estate | 2017 |
| Armeen Faiza Limited | Construction | 2024 |
| Armitage Civils Ltd | Construction | 2024 |
| Armiz Travels Limited | Transport & logistics | 2019 |
| Armour Food Group Limited | Other services | 2025 |
| Armour Foods Limited | Manufacturing | 2018 |
| Armoury Towers Management Limited | Households | 1990 |
| Arms Services Ltd | Administrative & support | 2024 |
| Armstrong & Capp Ltd | Financial services | 2019 |
| Armstrong Assets Unlimited | Professional & scientific | 2015 |
| Armstrong Aviation Limited | Extraterritorial | 2017 |
| Armstrong Aviation Management Services Limited | Transport & logistics | 2019 |
| Armstrong Brooks Limited | Financial services | 1988 |
| Armstrong Commercial Property Limited | Real estate | 2016 |
| Armstrong Leisure Limited | Extraterritorial | 2019 |
| Armstrong Software Limited | Information & communication | 2019 |
| Arnold Court Management Limited | Households | 1981 |
| Arnold Plant Hire Limited | Administrative & support | 1990 |
| Arnold Swift & SON (Longridge) Limited | Wholesale & retail | 1982 |
| Arnouts Ltd | Wholesale & retail | 2021 |
| Aroma Flower Co Ltd | Wholesale & retail | 2025 |
| Aromax Zone Ltd | Wholesale & retail | 2021 |
| Arora Medical Services Ltd | Health & social care | 2025 |
| Arosa Court Management Company Limited | Households | 1999 |
| Around the Box Ltd | Wholesale & retail | 2019 |
| Arpan Healthcare UK Limited | Health & social care | 2024 |
| Arpana Hathi Limited | Administrative & support | 2016 |
| Arqi Ltd | Professional & scientific | 2023 |
| Arrk Change and Transformation Ltd | Professional & scientific | 2026 |
| Arrow Emporium Ltd | Other services | 2025 |
| Arshay Limited | Real estate | 2025 |
| Art Battle Manchester Ltd | Arts & recreation | 2019 |
| Art Estetic Ltd | Administrative & support | 2013 |
| Art of Siam Thai Restaurant Limited | Hospitality | 2023 |
| Art Stop CIC | Arts & recreation | 2016 |
| Artaois Consulting Ltd | Professional & scientific | 2014 |
| Artees GOC Ltd | Wholesale & retail | 2025 |
| Artefract Limited | Information & communication | 1999 |
| Artemis Fibre Limited | Information & communication | 2023 |
| Artex Group Engineering Consultancy Ltd | Professional & scientific | 2024 |
| Artful Codger Limited | Professional & scientific | 2020 |
| Arthur Swallow Salvage Fairs Limited | Wholesale & retail | 2016 |
| Artin Express Ltd | Hospitality | 2024 |
| Artin Light Ltd | Professional & scientific | 2018 |
| Artingstall & Hind Limited | Other services | 2021 |
| Artis Opus Limited | Wholesale & retail | 2017 |
| Artisam Bespoke Limited | Hospitality | 2017 |
| Artisam Production Catering Ltd | Hospitality | 2025 |
| Artisan Cheese Ltd | Wholesale & retail | 2025 |
| Artisan Tile and Bathroom Studio Limited | Wholesale & retail | 2011 |
| Artist Vision Ltd | Administrative & support | 2007 |
| Artko Limited | Manufacturing | 2001 |