| Another Level Housing Ltd Ltd | Real estate | 2026 |
| Anthony Buckley & Constantine Limited | Professional & scientific | 1951 |
| Anthony Gauntlett Ltd | Other services | 2016 |
| Anti-Gravity Industries Limited | Wholesale & retail | 2021 |
| Antique Aura Ltd | Wholesale & retail | 2025 |
| Anvil Place Residents Management Company Limited | Households | 2025 |
| Anya Go Ltd | Transport & logistics | 2025 |
| AP Automation Solutions Limited | Professional & scientific | 2022 |
| Apartment Avenue Ltd | Extraterritorial | 2024 |
| Apartments Near ME Ltd | Real estate | 2024 |
| APC Renovation Ltd | Construction | 2023 |
| Apex Building Services West Midlands Ltd | Construction | 2025 |
| Apex Home Care Limited | Health & social care | 2024 |
| Apex Site Services Ltd | Administrative & support | 2020 |
| Apex Trading ( Midlands) Ltd | Transport & logistics | 2011 |
| Aposlo Studios Ltd | Information & communication | 2022 |
| Apple PIE Developments Limited | Construction | 2013 |
| Apple PIE Properties Limited | Real estate | 2012 |
| Applied Technology Limited | Professional & scientific | 2022 |
| APW Pharma Limited | Health & social care | 2016 |
| Aquacalor Ltd | Construction | 2025 |
| Aquamarine Energy Limited | Professional & scientific | 2004 |
| Aquavera Engineering Ltd | Professional & scientific | 2025 |
| Aquila Land Limited | Real estate | 2025 |
| AR Convenience Retail Ltd | Wholesale & retail | 2020 |
| ARC Interior Solutions Limited | Construction | 2006 |
| Arch Stanton Limited | Real estate | 2012 |
| Archava Scaffolding Limited | Construction | 2024 |
| Archer Stairlifts Limited | Manufacturing | 2021 |
| Archon Academy | Education | 2018 |
| Archon Combine Limited | Arts & recreation | 2010 |
| Arctic Smart Repairs Limited | Other services | 2013 |
| Ardor Properties Limited | Real estate | 2016 |
| Argonaut Community Enterprises C.I.C. | Administrative & support | 2010 |
| ARK 7 Solutions Ltd | Transport & logistics | 2018 |
| ARK Management Services (UK) Limited | Administrative & support | 2012 |
| Arkid Developments Ltd | Construction | 2015 |
| Arkid Twmpath Ltd | Construction | 2019 |
| ARM Electrical & Building Limited | Construction | 2017 |
| Armour Guard Films Limited | Administrative & support | 2004 |
| Armour Guard Security Films Limited | Administrative & support | 2022 |
| Armoured Electrical Solutions Limited | Construction | 2022 |
| Arns Events Limited | Professional & scientific | 2024 |
| Arron & Partners Ltd | Health & social care | 2025 |
| Artemis Young Person’S Care and Education Services Limited | Health & social care | 2016 |
| Arthur Associates Limited | Arts & recreation | 2002 |
| Arthursteenhorneadamson Ltd | Professional & scientific | 2003 |
| Artisan Crumb Ltd | Manufacturing | 2025 |
| Artleticsfc Ltd | Arts & recreation | 2025 |
| AS Direct Courier Ltd | Transport & logistics | 2025 |
| Asbreg Ltd | Information & communication | 2021 |
| Ascend Talent Limited | Administrative & support | 2023 |
| Ascent Access Holdings Limited | Financial services | 2022 |
| Ascent Access Scaffolding Limited | Construction | 2018 |
| Ascert Consulting Limited | Extraterritorial | 2010 |
| Asdr Property Management Ltd | Real estate | 2025 |
| ASF Builders and Plumbers Merchant Haleswon Ltd | Wholesale & retail | 2025 |
| ASH Roofing Services Limited | Construction | 2022 |
| Ashdale Care Homes Limited | Administrative & support | 1997 |
| Ashdale House (Pembroke) Management Company Limited | Households | 2016 |
| Ashley Law Bromsgrove Limited | Administrative & support | 2003 |
| Ashley Public Works Limited | Construction | 1967 |
| Ashley Would Estate Agents Limited | Real estate | 2020 |
| ASJ Tech Ltd | Wholesale & retail | 2025 |
| ASK Ideer Group Limited | Professional & scientific | 2026 |
| ASK Ideer Holdings Limited | Professional & scientific | 2026 |
| ASK4 Logistics Ltd | Transport & logistics | 2025 |
| Askthemarket Property Solutions Ltd | Real estate | 2023 |
| Asset & Programme Delivery Ltd | Professional & scientific | 2013 |
| Associate Interior Solutions Ltd | Manufacturing | 2008 |
| Asst Limited | Wholesale & retail | 2012 |
| Astral TV Limited | Information & communication | 2015 |
| Astro Info Service Ltd | Education | 2003 |
| Astute Numbers Limited | Professional & scientific | 2025 |
| Asuda Global Trade & Brokerage Ltd | Wholesale & retail | 2026 |
| AT Supplies Ltd | Wholesale & retail | 2000 |
| AT Wheel Refurb Ltd | Wholesale & retail | 2022 |
| ATC Developments Ltd | Construction | 2023 |
| Athaj Ltd | Wholesale & retail | 2020 |
| Atherton Chartwells Investments Limited | Real estate | 2022 |
| Atherton Chartwells Ltd | Real estate | 2024 |
| Atkins Wealth Consultancy Ltd | Financial services | 1999 |
| ATL Auto's Limited | Wholesale & retail | 2013 |
| ATL Autos (MOT) Limited | Wholesale & retail | 2017 |
| Atlas Aval (UK) Limited | Wholesale & retail | 2016 |
| Atlas GL Partners Limited | Wholesale & retail | 2022 |
| Atomic Healthcare Ltd | Health & social care | 2024 |
| Audi Ventures Limited | Wholesale & retail | 2022 |
| Audiog Limited | Health & social care | 2025 |
| AUH Driving Ltd | Education | 2026 |
| Aurora.M Tech Ltd | Wholesale & retail | 2025 |
| Austin Healey Club Limited | Other services | 1981 |
| Austin Walker Associates Limited | Professional & scientific | 2005 |
| Autistation Limited | Education | 2023 |
| Auto Car Junction Ltd | Wholesale & retail | 2025 |
| Automotive Accident Repairs Ltd | Wholesale & retail | 2023 |
| Autoserve Group Limited | Administrative & support | 2000 |
| Autoserve Limited | Administrative & support | 2008 |
| Autovention Limited | Information & communication | 2024 |
| AVA Event Styling Ltd | Professional & scientific | 2014 |