| AP SD Sixty Three Limited | Wholesale & retail | 2025 |
| Apeiron Construction Consultancy Ltd | Professional & scientific | 2025 |
| Apex 23 Site Engineering Ltd | Construction | 2023 |
| Apex Edge Holdings Ltd | Information & communication | 2021 |
| Apexx Associates UK Ltd | Professional & scientific | 2025 |
| APL 1 (West Malling) Limited | Construction | 2023 |
| APL 2 (West Malling) Limited | Construction | 2023 |
| APL Leisure Ltd | Arts & recreation | 2023 |
| Apollo Business Insights Ltd | Professional & scientific | 2025 |
| App Design DOT Company Limited | Information & communication | 2015 |
| Appeus Ltd | Information & communication | 2011 |
| Apragaz Limited | Professional & scientific | 2021 |
| AQ People Solutions Ltd | Professional & scientific | 2019 |
| Ar-Cardat Civil Engineering Ltd | Information & communication | 2026 |
| Arab Intelligence & Creativity Award Ltd | Financial services | 2024 |
| Arbitre Communications Limited | Professional & scientific | 2009 |
| Arcadian Consulting Limited | Professional & scientific | 2017 |
| Architects Match Limited | Information & communication | 2025 |
| Ardent Consulting Services Ltd | Professional & scientific | 2016 |
| Arfaha Crafts Limited | Wholesale & retail | 2024 |
| Argo Industrial Engines Limited | | 1985 |
| Arhconstruct Ltd | Construction | 2022 |
| Arirma Ltd | Financial services | 2022 |
| Arise Athlete Club Ltd | Education | 2024 |
| Arjc Consultancy Ltd | Information & communication | 2020 |
| Arkley Reprographics Ltd | Manufacturing | 2021 |
| ARL Asbestos Ltd | Administrative & support | 2005 |
| Artech Surveying Engineering Ltd | Professional & scientific | 2013 |
| Artificial Functions Ltd | Transport & logistics | 2022 |
| Artistem Limited | Health & social care | 2011 |
| Artrim Commercial Limited | Real estate | 2024 |
| Artrim Holdings Limited | Financial services | 2024 |
| Arum Press Limited | Professional & scientific | 1997 |
| ASG Consultancy Ltd | Professional & scientific | 2023 |
| Ashbourne Self-Assessment Services Limited | Professional & scientific | 1995 |
| Ashcorp Management Limited | Professional & scientific | 2022 |
| Ashe Property Ltd | Administrative & support | 2014 |
| Ashe Property Management Limited | Real estate | 2009 |
| Ashford Chimney Services Limited | Administrative & support | 2011 |
| Ashford Cowgirl Ltd | Hospitality | 2024 |
| Ashford Formwork and Reinforcment Ltd | Construction | 2023 |
| Ashford Outdoors Ltd | Wholesale & retail | 2022 |
| Ashgrove Property Services Limited | Real estate | 2004 |
| Ashley Light Engineering Ltd | Manufacturing | 2015 |
| Ashton IT Solutions Ltd | Information & communication | 1998 |
| Asset Instruments Engineering Limited | Professional & scientific | 2018 |
| Assisted Assessments Ltd | Health & social care | 2024 |
| Assistive E-Textiles CIC | Professional & scientific | 2026 |
| Association of Leasehold Enfranchisement Practitioners Limited | Professional & scientific | 2007 |
| Aston & Bridgewater Limited | Professional & scientific | 2007 |
| Aston & Bridgewater Properties Limited | Real estate | 2021 |
| Aston Court Freehold Company Ltd | Households | 2022 |
| Astrantia Property Ltd | Professional & scientific | 2019 |
| Asude Ltd | Hospitality | 2016 |
| AT Lifestyle Limited | Professional & scientific | 2018 |
| Atec - 3D Ltd | Professional & scientific | 2012 |
| Athena Horizons Limited | Information & communication | 2009 |
| Atir Management & Development Services Limited | Real estate | 2017 |
| Atir Solutions Limited | Real estate | 2021 |
| Atkorai Security Ltd | Administrative & support | 2025 |
| Atlanta Trust Limited | Manufacturing | 1976 |
| ATM Safety Consultants Ltd | Administrative & support | 2009 |
| Atman House Ltd | Other services | 2023 |
| ATO Technology Ltd | Wholesale & retail | 2020 |
| ATS (Folkestone) Ltd | Manufacturing | 1999 |
| ATT Property Ltd | Financial services | 2021 |
| Auag Services Ltd | Administrative & support | 2021 |
| Audioshock Limited | Information & communication | 2012 |
| Aumprema Limited | Wholesale & retail | 2025 |
| Aura Film Productions Ltd | Manufacturing | 2021 |
| Aurelius Innovations Ltd | Information & communication | 2026 |
| Autavia Properties Limited | Real estate | 2010 |
| Auto Diagnostics Centre Ltd | Wholesale & retail | 2015 |
| Auto Economy Centre Ltd | Wholesale & retail | 2015 |
| Auto Spa Canterbury Ltd | Wholesale & retail | 2025 |
| Auto Spa Detailing Ltd | Wholesale & retail | 2026 |
| Auto Spa the Flagship Ltd | Wholesale & retail | 2026 |
| Automotive Training Ltd | Education | 2008 |
| Autorite-Finishers Limited | Wholesale & retail | 1976 |
| AVA Store Ltd | Wholesale & retail | 2025 |
| Avant Consulting Ltd | Professional & scientific | 2003 |
| Avenay Court Freeholders Limited | Households | 2019 |
| Aviva Stone South East Limited | Wholesale & retail | 2015 |
| Avivo Limited | Wholesale & retail | 2020 |
| AVP Capel Limited | Professional & scientific | 2016 |
| AW Construction Services Ltd | Construction | 2013 |
| AW Labour Services Limited | Administrative & support | 2016 |
| AW Racing Limited | Arts & recreation | 2021 |
| AW Rail Services Ltd | Construction | 2012 |
| Awaken With ME Ltd | Health & social care | 2019 |
| AWE South East Ltd | Professional & scientific | 2022 |
| Aylett Motor Sport Limited | Wholesale & retail | 2022 |
| Azkadinya Ltd | Arts & recreation | 2023 |
| B Cleaning & Maintenance Ltd | Administrative & support | 2026 |
| B E Brisley & SON | | 1998 |
| B for Broady Ltd | Professional & scientific | 2026 |
| B Mechanical Ltd | Professional & scientific | 2024 |
| B Young Grounds Maintenance Limited | Administrative & support | 2016 |
| B&L Vehicle Services Ltd | Wholesale & retail | 2025 |
| B-Tek Concrete Consultancy Limited | Professional & scientific | 2019 |