| ARA Property Services Limited | Real estate | 2024 |
| ARA Recovery and Assist Limited | Other services | 2025 |
| ARA Vehicle Solutions Limited | Administrative & support | 2024 |
| ARB Transport UK Limited | Transport & logistics | 2018 |
| ARC Cosmetic Clinic Ltd | Other services | 2021 |
| ARC Eco Solutions Ltd | Construction | 2025 |
| ARC Metal Design Ltd | Manufacturing | 2022 |
| Arcato Limited | Manufacturing | 2025 |
| Archeonic Ltd | Information & communication | 2026 |
| Arches & Aisles Ltd | Hospitality | 2026 |
| Arel Holdings Limited | Professional & scientific | 2017 |
| Arenga Group Limited | Wholesale & retail | 2018 |
| Aria Global and Logistics Limited | Transport & logistics | 2021 |
| Aris Trucks Ltd | Transport & logistics | 2025 |
| Arnold K SOT Limited | Wholesale & retail | 2009 |
| Arohana Properties Ltd | Real estate | 2023 |
| Arora Projects Limited | Real estate | 2025 |
| Arrayan Jewellery Ltd | Wholesale & retail | 2025 |
| Arrys Taxi Ltd | Transport & logistics | 2025 |
| Art Logistics Limited | Water & waste | 2026 |
| Artisan Vapor Oldbury Ltd | Wholesale & retail | 2017 |
| AS Couriers U.K. Limited | Transport & logistics | 2022 |
| AS Motors and Recovery Ltd | Wholesale & retail | 2024 |
| AS Primepath Ltd | Professional & scientific | 2026 |
| AS Technical Engineering Ltd | Manufacturing | 2019 |
| ASA Builders Ltd | Construction | 2018 |
| Asad Adris Associates Limited | Other services | 2014 |
| Asante Logistics Ltd | Transport & logistics | 2026 |
| Asap Couriers Ltd | Transport & logistics | 2025 |
| ASB Optical Ltd | Health & social care | 2019 |
| ASC Network Ltd | Construction | 2026 |
| ASC Scaffolding Limited | Administrative & support | 2002 |
| Ascend Education and Training Ltd | Real estate | 2021 |
| Ascend Logistics Midlands Ltd | Transport & logistics | 2025 |
| Ascend Properties Ltd | Real estate | 2025 |
| Ascendix Ltd | Information & communication | 2023 |
| ASH Accountant Limited | Professional & scientific | 2018 |
| ASH Smartrepairs Ltd | Wholesale & retail | 2025 |
| Ashford Court (Ashford Carbonel) Management Company Limited | Households | 2023 |
| Ashland Business Limited | Financial services | 2025 |
| Ashmam Ltd | Wholesale & retail | 2025 |
| Asiduo Consultancy Group Ltd. | Professional & scientific | 2017 |
| ASK Embankment 100 LLP | | 2014 |
| ASK Peloton Limited | Construction | 2023 |
| ASK Psych Ltd | Health & social care | 2025 |
| ASK Real Estate (Investments) Limited | Real estate | 2014 |
| ASK Real Estate Limited | Construction | 2012 |
| ASK Real Estate MBP Limited | Construction | 2025 |
| ASK Real Estate Property Limited | Construction | 2025 |
| Asnr Limited | Professional & scientific | 2018 |
| Aspire Careers Consultancy Limited | Professional & scientific | 2012 |
| Aspire Support Group Ltd | Administrative & support | 2025 |
| Association for Glycogen Storage Disease (UK) Limited | Health & social care | 2009 |
| Astley C Limited | Wholesale & retail | 2024 |
| Aston James Construction Ltd | Construction | 2020 |
| Astra Systems LP | | 2026 |
| Astral North Holdings Ltd | Financial services | 2021 |
| Astro 8 Ltd | Information & communication | 2026 |
| Atfi Limited | Financial services | 2018 |
| Athwal Resourcing Limited | Administrative & support | 2012 |
| Atkins Property Solutions Ltd | Real estate | 2024 |
| ATL Trustees Ltd | Financial services | 2017 |
| Atny Ltd | Professional & scientific | 2022 |
| Atomic Security Ltd | Administrative & support | 2011 |
| Atoztravelsolution Ltd | Administrative & support | 2025 |
| ATT Hair Salon Ltd | Other services | 2022 |
| Attic Barrel Store JQ Ltd | Manufacturing | 2022 |
| Attic Brew Co. Ltd | Manufacturing | 2018 |
| Attic Holdco Limited | Financial services | 2025 |
| Attic Propco Limited | Financial services | 2025 |
| Atwal Logistics Ltd | Transport & logistics | 2025 |
| Auction House TV. COM Ltd | Construction | 2019 |
| Aujla Accountancy Ltd | Professional & scientific | 2024 |
| Aujla Holdings Ltd | Real estate | 2023 |
| Aulak Property Ltd | Real estate | 2019 |
| AUM Consultancy PVT. Ltd | Other services | 2016 |
| Aura Vista Ltd | Real estate | 2025 |
| Aurami Services Ltd | Wholesale & retail | 2024 |
| Auto Align Ltd | Wholesale & retail | 2021 |
| Autobody Services Ltd | Wholesale & retail | 2024 |
| Autogold Limited | Transport & logistics | 2025 |
| Automatic Letter Bender UK Ltd | Wholesale & retail | 2016 |
| Automaxx AI Technologies Ltd | Information & communication | 2025 |
| Automotive Regenerations Ltd | Wholesale & retail | 2014 |
| Automrok 2 Limited | Wholesale & retail | 2025 |
| Autopoint (Oldbury) Ltd | Wholesale & retail | 2026 |
| Autotutor Driving School Ltd | Education | 2022 |
| AV Beauty Ltd | Other services | 2026 |
| AV Clinic Ltd | Other services | 2023 |
| AV Real Estate City Ltd | Real estate | 2024 |
| AV Vehicle Solutions Ltd | Wholesale & retail | 2021 |
| Avanti Properties Ltd | Real estate | 2019 |
| Avanti Training Solutions Ltd | Administrative & support | 2025 |
| Avas Home Improvements Ltd | Construction | 2020 |
| Avaz Designs Ltd | Professional & scientific | 2016 |
| Avenue Foods Ltd | Hospitality | 2019 |
| Avery Football Club CIC | Education | 2025 |
| Avijas Transport Limited | Transport & logistics | 2024 |
| Avinchi Ltd | Wholesale & retail | 2023 |
| Avinchi Properties Ltd | Real estate | 2025 |