| Apex Eco Store Limited | Wholesale & retail | 2024 |
| Apex Reign Management Ltd | Wholesale & retail | 2025 |
| Apex Sustainability Group Limited | Financial services | 2024 |
| Apollo Damp Proofing Ltd | Construction | 2018 |
| Apollo Residential Lettings Limited | Real estate | 2020 |
| Apostol P3 Ltd | Transport & logistics | 2026 |
| Apple Deal 2 Ltd | Construction | 2021 |
| Apple Deal Investments Limited | Construction | 2020 |
| Applied Graphics Limited | Manufacturing | 1999 |
| APV Trade Solution Ltd | Wholesale & retail | 2014 |
| Aqua Industrial Limited | Transport & logistics | 1999 |
| Ar-Control Systems Limited | Manufacturing | 2017 |
| ARA 1 Ltd | Wholesale & retail | 2026 |
| Arab European Investment Corp. Limited | Energy | 2017 |
| Arbsuitepro Ltd | Information & communication | 2026 |
| Arch Premier Properties Limited | Real estate | 2004 |
| Arch Project Services Ltd | Professional & scientific | 2024 |
| Archahi Retail Ltd | Wholesale & retail | 2021 |
| Archbee Plumbing and Heating Ltd | Construction | 2026 |
| Archer Landscapes Limited | Administrative & support | 2003 |
| Archirondal Management Ltd | Households | 2021 |
| Arcola Holdings Limited | Real estate | 2021 |
| Arcola Products Limited | Manufacturing | 1971 |
| Ardea Holdings Limited | Administrative & support | 1988 |
| Ardyssuk Limited | Administrative & support | 2013 |
| Arete Consultancy Services Ltd | Information & communication | 2015 |
| Arexar Limited | Real estate | 2014 |
| Arial Consultancy Limited | Professional & scientific | 2014 |
| Aries House Limited | Real estate | 2025 |
| Arlene Cosmetics Ltd | Wholesale & retail | 2025 |
| Arlex Services Limited | Professional & scientific | 2016 |
| ARM Brickwork Limited | Construction | 2025 |
| ARM Courier Services Ltd | Transport & logistics | 2020 |
| ARM FM Limited | Administrative & support | 2025 |
| Armatec Environmental Ltd | Manufacturing | 2018 |
| Armora Ltd | Administrative & support | 2026 |
| Aroda Fashion Ltd | Wholesale & retail | 2024 |
| Aros Auto Accident Repair Ltd | Administrative & support | 2017 |
| Arreh Ltd | Real estate | 2026 |
| Art Panda Ltd | Wholesale & retail | 2024 |
| Arthur Marine Ltd | Agriculture & fishing | 2013 |
| Artjom OS Ltd | Wholesale & retail | 2021 |
| Arvanza Limited | Professional & scientific | 2008 |
| Arys Engineering Limited | Professional & scientific | 2011 |
| Ascoli Group Ltd | Professional & scientific | 2018 |
| Ascot Park Limited | Construction | 2010 |
| ASH Lane Management Ltd | Households | 2017 |
| Asher Projects Limited | Real estate | 2025 |
| Ashrock Construction Ltd | Construction | 2025 |
| Ashvin Properties Limited | Real estate | 2006 |
| ASK Desserts Ltd | Hospitality | 2023 |
| ASK the Mechanic Ltd | Wholesale & retail | 2012 |
| Aspect BIM Services Ltd | Administrative & support | 2012 |
| Aspire Payroll Limited | Professional & scientific | 2025 |
| Assist Associates Ltd | Professional & scientific | 2015 |
| Assock Limited | Other services | 2019 |
| Assured Electrical Contractors Limited | Construction | 2007 |
| Assured Electrical Partnership LLP | | 2013 |
| Assured Property Investments Ltd | Real estate | 2018 |
| Astrotex Limited | Construction | 2013 |
| AT Corporation Limited | Information & communication | 2014 |
| At&T ALL Truck & Trailers Kent Ltd | Wholesale & retail | 2026 |
| Atform Services Limited | Professional & scientific | 2015 |
| Atlantic Business Supplies Limited | Wholesale & retail | 2016 |
| ATM Pharma Ltd | Wholesale & retail | 2024 |
| Atomy Achievers Centre Ltd | Education | 2024 |
| Atse Building Services Ltd | Construction | 2026 |
| Attire Hire Limited | Wholesale & retail | 2024 |
| Attlee Way (Sittingbourne) Residents Management Company Limited | Households | 2015 |
| Au-Pair International Ltd. | Extraterritorial | 2002 |
| Audry Consult Ltd | Information & communication | 2024 |
| Aurea Praxis Ltd | Real estate | 2013 |
| Auroralane Group Ltd | Manufacturing | 2025 |
| Austin Contract Services Limited | Construction | 1999 |
| Austin Joinery LLP | | 2016 |
| Auto Collective Ltd | Wholesale & retail | 2023 |
| Autoration Motors Ltd | Wholesale & retail | 2025 |
| Autoworld (South East) Limited | Wholesale & retail | 2000 |
| Autumn Groundcare Ltd | Administrative & support | 2025 |
| AV Statutory Inspections Ltd | Professional & scientific | 2022 |
| AV Stays Mgmt Ltd | Real estate | 2023 |
| Avallure Ltd | Other services | 2025 |
| Avantly Ltd | Extraterritorial | 2015 |
| Avensis IT Services Ltd | Information & communication | 2022 |
| Aventa Restaurants Limited | Administrative & support | 2002 |
| Aventro Consulting Limited | Professional & scientific | 2025 |
| Avenuez Limited | Real estate | 2024 |
| AVN Construction Ltd | Construction | 2014 |
| Avoda Private Limited | Health & social care | 2014 |
| Avsec Solutions Limited | Professional & scientific | 2023 |
| AWE Security Ltd | Administrative & support | 2019 |
| Awmity Ltd | Professional & scientific | 2009 |
| Awoyemi QA Ltd | Information & communication | 2017 |
| AX4 Limited | Health & social care | 2021 |
| Axford Court Management Limited | Households | 1994 |
| Axia Chemicals Ltd | Manufacturing | 2010 |
| AY & TEE Healthcare Services Ltd | Health & social care | 2016 |
| Aykem Limited | Real estate | 2021 |
| AYM Transport Ltd | Other services | 2023 |
| Ayrjem Building and Maintenance Limited | Construction | 2022 |