| ALL FIX Property Refurbishment Ltd | Construction | 2024 |
| ALL Harmony Ltd | Professional & scientific | 2025 |
| ALL Yours Period Box C.I.C. | Other services | 2021 |
| Allarmed Limited | Manufacturing | 2022 |
| Allfarthing Ltd | Construction | 2023 |
| Allwin Tax Services Limited | Other services | 2005 |
| Alpha Energy Ltd | Administrative & support | 2019 |
| Alpha William Ltd | Administrative & support | 2026 |
| ALR Spirit Ltd | Manufacturing | 2025 |
| Altrucom Limited | Wholesale & retail | 1998 |
| ALY Vance Media Ltd | Information & communication | 2012 |
| AMA Dhami Limited | Wholesale & retail | 2014 |
| Amanda Gaul Holdings Limited | Construction | 2016 |
| Amanda Gaul Limited | Construction | 2016 |
| Amel Electrical Ltd | Construction | 2021 |
| Amery Publishing Ltd | Information & communication | 2025 |
| Amont Limited | Professional & scientific | 2022 |
| Ample Care Ltd | Administrative & support | 2025 |
| Ample Logistics Limited | Transport & logistics | 2026 |
| Amtech Business Solutions Limited | Information & communication | 2013 |
| Amtech Holdings Limited | Information & communication | 2021 |
| Andrew Brown 57 Limited | Professional & scientific | 2000 |
| Andrew Wicks Creative Limited | Professional & scientific | 2011 |
| Andy Jones Window Cleaning Ltd | Administrative & support | 2019 |
| Angus Lodge Holdings Ltd | Administrative & support | 2018 |
| Angus Studd Countryside Services Ltd | Agriculture & fishing | 2019 |
| Ania Financial Consulting Limited | Professional & scientific | 2020 |
| Anmol Property Services Ltd | Real estate | 2024 |
| Annetts Services Ltd | Wholesale & retail | 2015 |
| Annie Bells International Bicycle Bell Boutique Ltd | Wholesale & retail | 2023 |
| Anywhere Properties Limited | Real estate | 2023 |
| Apex Building & Groundworks Ltd | Construction | 2019 |
| Apis Accounting Limited | Professional & scientific | 2025 |
| APJ Services Ltd | Administrative & support | 2014 |
| Appletree Training Ltd | Information & communication | 2020 |
| April RAE Holdings Limited | Financial services | 2022 |
| April RAE Investments Ltd | Real estate | 2025 |
| Aquaheat Technical Services Ltd | Construction | 2019 |
| Aquaworx Plumbing Limited | Construction | 2024 |
| ARC One Welding Limited | Construction | 2019 |
| Arcanum Holding Ltd | Financial services | 2023 |
| Arcanum Properties Ltd | Real estate | 2018 |
| Argylestone Consulting Ltd | Administrative & support | 2022 |
| ARK Homes Ltd | Construction | 2011 |
| Arnik Engineering Limited | Professional & scientific | 2007 |
| Arniss Equestrian Limited | Arts & recreation | 2011 |
| ARR Growth Partners Limited | Professional & scientific | 2018 |
| Arsha Kula Limited | Other services | 2017 |
| Arthur's PAL Ltd | Other services | 2025 |
| Ascot & Rose Limited | Construction | 2020 |
| Ascot Asset Management Limited | Financial services | 1998 |
| Ashentree Ltd | Professional & scientific | 2022 |
| Ashford Retail Services Limited | Construction | 2012 |
| Ashgood's Electrical and Maintenance Ltd | Construction | 2021 |
| Ashmore Green Garage Limited | Real estate | 1973 |
| Ashton Airline Advisory Ltd | Professional & scientific | 2020 |
| Askwith Properties Ltd | Real estate | 2012 |
| Asset Leasing & Finance Limited | Financial services | 2019 |
| Association of Renal Industries Ltd | Other services | 2006 |
| AT Bespoke Carpentry & Joinery Limited | Manufacturing | 2018 |
| ATK Studio Ltd | Administrative & support | 2020 |
| Atomic Fitness Ltd | Other services | 2014 |
| ATS Technologies Ltd | Information & communication | 2013 |
| Attfield Enterprises Ltd | Professional & scientific | 2017 |
| Attif News Limited | Other services | 2011 |
| Audrey Becker Limited | Wholesale & retail | 2014 |
| Auto Bodyworx Minor Body Repairs Ltd | Wholesale & retail | 2022 |
| Autocrash UK Limited | Wholesale & retail | 2006 |
| Automotive Glazing and Adas Training Solutions Limited | Education | 2024 |
| Autotek Services Ltd | Wholesale & retail | 2015 |
| Avado Limited | Manufacturing | 2012 |
| AVE Cabs Ltd | Administrative & support | 2019 |
| Aviard Limited | Information & communication | 2005 |
| Avlex Ltd | Professional & scientific | 2016 |
| Avron Trading Limited | Wholesale & retail | 2002 |
| Awash Laundry Ltd | Other services | 2010 |
| Awberry Precision Ltd | Professional & scientific | 2005 |
| AWS Communications Limited | Real estate | 1977 |
| Axolotl Structural Limited | Construction | 2018 |
| Aynsley FRY Limited | Health & social care | 2014 |
| Azura Heating & Plumbing Ltd | Construction | 2011 |
| B and D Gordon Ltd | Other services | 2014 |
| B&A Construction Berkshire Ltd | Construction | 2025 |
| B&Gb Holdings Ltd | Real estate | 2016 |
| B.Cool A/C Limited | Construction | 2020 |
| Baker Street Press Limited | Information & communication | 2015 |
| Balance Work and Wellbeing Ltd | Professional & scientific | 2022 |
| Bambooty Limited | Wholesale & retail | 2008 |
| Bamboozledai Ltd | Education | 2025 |
| Bambury Consulting Limited | Professional & scientific | 2017 |
| Barclay Madison Ltd | Health & social care | 2021 |
| Barj Homes Ltd | Real estate | 2025 |
| Barlow & Sons (Hermitage) Limited | Manufacturing | 1964 |
| Barnard Management Limited | Financial services | 2011 |
| Baron Vape Labs Ltd | Wholesale & retail | 2019 |
| Barr Engineering Limited | Professional & scientific | 2013 |
| Barrett Estate Services Limited | Construction | 1971 |
| Barrett Family Holdings Limited | Financial services | 2011 |
| Barrie P Smith Ltd | Professional & scientific | 2014 |
| Barry Newman Golf Ltd. | Wholesale & retail | 2016 |