| Arosi Decor Ltd | Hospitality | 2020 |
| ARP Social Ltd | Professional & scientific | 2023 |
| Arpoador Limited | Real estate | 2007 |
| Arra V Limited | Construction | 2012 |
| Arri (GB) Limited | Wholesale & retail | 1982 |
| Arri Cine Technik Ltd | Wholesale & retail | 2009 |
| Arri Rental Services UK Limited | Administrative & support | 1986 |
| Arrivia Europe Limited | Administrative & support | 1999 |
| Arrivia Travel UK Limited | Administrative & support | 2009 |
| Arrk Alliance Ltd | Professional & scientific | 2022 |
| ARS Care Ltd | Health & social care | 2025 |
| ARS Markit Ltd | Wholesale & retail | 2025 |
| Arshi Abaya Limited | Wholesale & retail | 2026 |
| Arsiwala Ltd | Real estate | 2023 |
| Art and Gallery Bar Ltd | Real estate | 2024 |
| Art Build and Landscape Ltd | Construction | 2026 |
| Art by Law Limited | Professional & scientific | 2013 |
| Art Hotels Peterborough Limited | Hospitality | 2019 |
| Art Public House Ltd | Real estate | 2024 |
| Art.Design Interiors UK Ltd | Construction | 2011 |
| Artch Design Construction Ltd | Construction | 2020 |
| Artemis Access Scaffolding Limited | Extraterritorial | 2019 |
| Artemis Construction Limited | Extraterritorial | 2019 |
| Arthur Chops Limited | Construction | 2022 |
| Article Ltd | Professional & scientific | 2014 |
| Artis Partners LLP | | 2024 |
| Artisan Software Solutions Limited | Professional & scientific | 2025 |
| Artistic Homes London Ltd | Wholesale & retail | 2025 |
| Artsill Limited | Professional & scientific | 1998 |
| Artwood Limited | Manufacturing | 2018 |
| ARU Constructions Ltd | Construction | 2023 |
| Arundel Gardens Property Management Limited | Households | 2015 |
| Arundel Land Limited | Real estate | 2022 |
| Aryansoft Limited | Information & communication | 2017 |
| ARZ Superstore Ltd | Wholesale & retail | 2023 |
| AS Associates Builders & Developers Ltd | Construction | 2025 |
| AS Enforcement Ltd | Administrative & support | 2025 |
| AS Food & Wine Ltd | Wholesale & retail | 2014 |
| AS Naseri Ltd | Health & social care | 2025 |
| AS7 Investments Limited | Real estate | 2020 |
| ASA Property Investments Ltd | Real estate | 2020 |
| ASA Venture Limited | Real estate | 2025 |
| Asabeauty Ltd | Wholesale & retail | 2012 |
| Asapbuildandrefurbish Limited | Construction | 2025 |
| Ascendric Commercial Property Group Ltd | Real estate | 2026 |
| Ascendric Ltd | Transport & logistics | 2025 |
| Ascendric Property Group Ltd | Real estate | 2026 |
| Ascent Business Support Ltd. | Information & communication | 2004 |
| Ascox Limited | Wholesale & retail | 2023 |
| ASG Capital Ltd | Real estate | 2024 |
| ASG UK Investments Ltd | Financial services | 2024 |
| Asgf Limited | Construction | 2013 |
| Asghar Nazir Ltd | Wholesale & retail | 2018 |
| ASH Barbar Shop Ltd | Other services | 2026 |
| ASH Estates London Ltd | Real estate | 2024 |
| ASH Medical Services Ltd | Professional & scientific | 2023 |
| Asha London Limited | Wholesale & retail | 2011 |
| Ashcot Limited | Financial services | 2026 |
| Ashcroft House Limited | Health & social care | 1997 |
| Ashgrove Residences Ltd | Real estate | 2024 |
| Ashirwad 2 Properties Ltd | Real estate | 2013 |
| Ashkun Ltd | Wholesale & retail | 2022 |
| Ashley Road Developments Ltd | Real estate | 2026 |
| Ashring House Limited | Health & social care | 1997 |
| Ashta Inc Ltd | Real estate | 2023 |
| Ashton & Co Accountants Limited | Professional & scientific | 2015 |
| Ashtree House Residents Association Limited | Real estate | 1996 |
| Ashveen Properties Ltd | Real estate | 2025 |
| Ashview House Limited | Health & social care | 1997 |
| Asian K Associates Limited | Real estate | 2025 |
| ASK ME Health Limited | Health & social care | 2018 |
| ASK ME Limited | Professional & scientific | 2015 |
| ASK Shop Fitter Limited | Construction | 2020 |
| Askat Ltd | Real estate | 2020 |
| Aslan B2B Limited | Professional & scientific | 2019 |
| ASM Property & Management Limited | Real estate | 2016 |
| ASP Global Limited | Administrative & support | 2013 |
| Aspirs Ltd | Information & communication | 2015 |
| ASS Logistics Ltd | Transport & logistics | 2024 |
| ASS Trading Limited | Wholesale & retail | 2025 |
| Assemble Pictures Ltd | Information & communication | 2012 |
| Asset Bricks Ltd | Construction | 2018 |
| Asset Centrix Ltd | Information & communication | 2025 |
| Asset Inheritance Ltd | Information & communication | 2025 |
| Assi Construction Ltd | Construction | 2019 |
| Assign US Consulting Limited | Professional & scientific | 2015 |
| Associated Building Maintenance Limited | Construction | 1989 |
| Associated Contract Services Limited | Administrative & support | 2002 |
| Assured Computer Solutions Limited | Information & communication | 2002 |
| AST Investments Limited | Extraterritorial | 2021 |
| Astenway Building Contractors Limited | Construction | 2005 |
| Astenway Homes Limited | Real estate | 2014 |
| Astenway Limited | Construction | 2002 |
| Astley Baker Davies Limited | Administrative & support | 2007 |
| Aston Heights Management Limited | Construction | 2020 |
| Aston Trading Ltd | Wholesale & retail | 2020 |
| Astral Cleaning Services Limited | Administrative & support | 2011 |
| Astril Rigging Limited | Construction | 2021 |
| Asuman Ltd | Transport & logistics | 2025 |
| ASV EOE Limited | Hospitality | 2021 |