| Amber Property Developments Ltd | Other services | 2003 |
| Amber Securities Ltd | Real estate | 2019 |
| Amber Sourcing Ltd | Real estate | 2019 |
| Amber Storage Ltd | Real estate | 2021 |
| Ambis Ltd | Information & communication | 2007 |
| Ambleside (Kendal Road) Management Company Limited | Households | 2004 |
| Ambro City Takeaway Limited | Hospitality | 2026 |
| AMC Heating Limited | Construction | 2003 |
| AMD Advisory Limited | Wholesale & retail | 2024 |
| Amdega Brands Limited | Wholesale & retail | 1997 |
| Amelul Limited | Administrative & support | 2010 |
| Amenity Services Limited | Households | 1987 |
| AMG Fire Solutions Limited | Manufacturing | 2017 |
| Ammar Ecom Ltd | Wholesale & retail | 2025 |
| Amnora Limited | Professional & scientific | 2025 |
| Amon Interactive Limited | Information & communication | 2011 |
| Amos Capital Asset Management Ltd | Professional & scientific | 2021 |
| Ampulse Electrical Services Ltd | Construction | 2014 |
| Amtrack Business Management Group Ltd. | Professional & scientific | 2016 |
| Amuk Services Limited | Wholesale & retail | 2016 |
| AN Training Solutions Limited | Professional & scientific | 2006 |
| Anagas Limited | Manufacturing | 2002 |
| ANC Projects Limited | Professional & scientific | 2017 |
| Anca Investments Ltd | Financial services | 2004 |
| Anchor Bookkeeping Ltd | Professional & scientific | 2024 |
| Anchor Property (West Midlands) Ltd | Construction | 2020 |
| Ancoro Limited | Information & communication | 2014 |
| Anderson and Meyrick Limited | Professional & scientific | 2011 |
| Anderson Group of Companies Ltd | Financial services | 2016 |
| Anderson Health Limited | Arts & recreation | 1998 |
| Andover (36-47 the Elms) Residents Association Limited | Households | 1985 |
| Andracca Capital Ltd. | Professional & scientific | 2016 |
| Andrea Pope-Smith Associates Limited | Professional & scientific | 2014 |
| Andrew and David Dutton Ltd | Agriculture & fishing | 2003 |
| Andrew C. Davies Holdings Limited | Agriculture & fishing | 2010 |
| Andrew Hotchkiss Electrical Ltd | Construction | 2015 |
| Andrews Building Conservation Ltd | Professional & scientific | 2012 |
| Andrews Orme & Hinton Limited | Professional & scientific | 2002 |
| Andrisca Property Services Ltd | Construction | 2025 |
| Andy Jones (Shropshire) Limited | Professional & scientific | 2025 |
| Angel Pavement Management Company Limited | Households | 1998 |
| Angels & Demons Limited | Other services | 2020 |
| Angels Meadow Ltd | Manufacturing | 2020 |
| Angharad Studio Limited | Manufacturing | 2022 |
| Anglo Celtic Limited | Construction | 2002 |
| Angloda Technologies Ltd | Information & communication | 2026 |
| Aniebona Consulting Ltd | Health & social care | 2023 |
| Animal Transit Boxes Limited | Manufacturing | 2014 |
| Animositas Limited | Financial services | 2018 |
| Ankerpoint Ltd | Wholesale & retail | 2025 |
| Ann's Legacy Ltd | Real estate | 2025 |
| Anna Coroneo Ltd | Arts & recreation | 2012 |
| Annabel JAY Property Ltd | Real estate | 2026 |
| Annapurna Incorporated Limited | Financial services | 2023 |
| Annapurna Motorhomes Ltd | Manufacturing | 2015 |
| Anne Whysall Limited | Wholesale & retail | 2015 |
| Annsbrook Holdings Ltd | Construction | 2024 |
| Anrol Realisations Limited | Real estate | 2024 |
| Anscombe Engineering Limited | Other services | 2003 |
| Anterga Limited | Wholesale & retail | 2025 |
| Anthemion Antiques & Interiors Ltd | Wholesale & retail | 2025 |
| Anthony J. Matthews, B.Sc., F.C.A. Ltd | Professional & scientific | 2013 |
| Anthony Lewis Limited | Manufacturing | 2014 |
| Anthony Thomas Homes Ltd | Construction | 2018 |
| Anthropy Ltd | Information & communication | 2020 |
| Antico Guianao Limited | Hospitality | 2026 |
| Antique Exports UK Ltd | Wholesale & retail | 2025 |
| Anville Court Care Limited | Health & social care | 2016 |
| Anwyl Investments Limited | Financial services | 2025 |
| Aokal Investments Limited | Real estate | 2025 |
| Apex Accounting Solutions Limited | Professional & scientific | 2013 |
| Apex AI Limited | Professional & scientific | 2025 |
| Apex Refurbs and Construction Ltd | Construction | 2024 |
| APL Caravan Sales Limited | Wholesale & retail | 2022 |
| Apollo (Hub E & M) Limited | Professional & scientific | 2014 |
| Apollo (Hub Inverclyde) Limited | Real estate | 2015 |
| Apollo (Hub Investment) Holdings Ltd | Financial services | 2018 |
| Apollo (Hub Investment) Limited | Professional & scientific | 2016 |
| Apollo (Hub W & G) Limited | Real estate | 2016 |
| Apollo (Hub West) Limited | Professional & scientific | 2002 |
| Apperley Way (Block C) RTM Company Limited | Households | 2017 |
| Apperley Way (Block B) RTM Company Limited | Households | 2017 |
| Apperley Way (Block D) RTM Company Limited | Households | 2017 |
| Appforge.Uk Ltd | Information & communication | 2022 |
| Apple Colour Ltd | Manufacturing | 2016 |
| Apple Litho (Bristol) Ltd | Manufacturing | 1987 |
| Applied Seismology Consulting Ltd. | Professional & scientific | 1997 |
| Applied Techniques Limited | Professional & scientific | 2020 |
| Apps Cottages Ltd | Hospitality | 2026 |
| Apricate Energy Ltd | Energy | 2017 |
| Apricus Care Ltd | Health & social care | 2020 |
| Apricus Property Limited | Real estate | 2014 |
| Aproc Ltd | Construction | 2025 |
| APT Photography Ltd | Professional & scientific | 2013 |
| Aquarius Window Cleaning Services Limited | Administrative & support | 2007 |
| AR Study Gate Consultants Limited | Professional & scientific | 2026 |
| Arabellaboutique Ltd | Wholesale & retail | 2024 |
| ARB Engineering Services Ltd | Professional & scientific | 2024 |
| Arbour (Helsby) Management Limited | Households | 2007 |
| Arbserv Limited | Agriculture & fishing | 2011 |