| Admc Holdings Ltd | Financial services | 2022 |
| Adriginal Ltd | Professional & scientific | 2014 |
| Adventureholidaycentre Ltd | Administrative & support | 2014 |
| Adviser Services Group Holdings Limited | Financial services | 2024 |
| Adviser Services Holdings Limited | Financial services | 2019 |
| Adviser Services Holdings Wealth Management Limited | Extraterritorial | 2023 |
| Advocate Legal Services Limited | Professional & scientific | 2011 |
| Aerofoil Properties Ltd | Real estate | 2023 |
| Affluere Property Investments Limited | Real estate | 2023 |
| Affordable Hub Ltd | Hospitality | 2019 |
| Afjm Ltd | Professional & scientific | 2025 |
| AFS Literary Foundation Limited | Administrative & support | 2025 |
| AFU Stoves Ltd | Construction | 2022 |
| AFW Finance 2 Limited | Professional & scientific | 2015 |
| AG Facility Management Ltd | Administrative & support | 2023 |
| Agent Zoru Limited | Wholesale & retail | 2026 |
| Agile Project Services Ltd | Administrative & support | 2024 |
| Agilinx Ltd | Professional & scientific | 2002 |
| AGM Scaffolding Limited | Construction | 2012 |
| AGS Business Solutions Ltd | Professional & scientific | 2012 |
| Ahmss Ltd | Health & social care | 2023 |
| Ahxdh Ltd | Professional & scientific | 2014 |
| Aido Group Limited | Financial services | 2018 |
| Aido Investments Limited | Construction | 2016 |
| AJ Knutsford Developments Ltd | Construction | 2025 |
| AJ National Fire Limited | Public administration | 2019 |
| AJS Tax Consultancy Limited | Professional & scientific | 2026 |
| AK Maintain Ltd | Construction | 2022 |
| AK Shine Limited | Other services | 2020 |
| AKM Property Consultants Limited | Real estate | 2013 |
| AL and CEE Limited | Professional & scientific | 2022 |
| AL Core Partners Limited | Information & communication | 2019 |
| AL Core Technologies Limited | Information & communication | 2023 |
| Alamco Projects Ltd | Construction | 2007 |
| Alan Bethell Limited | Agriculture & fishing | 2009 |
| Albis (U.K.) Limited | Manufacturing | 1966 |
| Alchemy Capital Group Limited | Financial services | 2025 |
| Alderley Financial Planning Ltd | Professional & scientific | 2022 |
| Aldwarden Care Ltd | Real estate | 2025 |
| Aldwarden Limited | Real estate | 2011 |
| Alex&Er Jewellery Limited | Wholesale & retail | 2017 |
| Alexandra Thompson Interiors Limited | Other services | 2008 |
| Alison Gayton Enterprises Limited | Wholesale & retail | 2020 |
| ALK Fitness Limited | Other services | 2023 |
| ALL in the Loop Ltd | Information & communication | 2014 |
| ALL Sports Chairs Limited | Manufacturing | 2021 |
| ALL Turf Limited | Wholesale & retail | 2003 |
| Allhaven Limited | Financial services | 1988 |
| Allisonwhiteley Ltd | Information & communication | 2015 |
| Allphase M&E Ltd | Energy | 2024 |
| Allseas UK Limited | Construction | 1994 |
| Alpen UK Limited | Wholesale & retail | 1995 |
| Altabani Ltd | Administrative & support | 2019 |
| Altrincham Security Installations Ltd | Administrative & support | 2008 |
| ALX Property Ltd | Real estate | 2025 |
| Amanda Hilton Counselling Ltd | Health & social care | 2025 |
| Amandaleg Ltd | Wholesale & retail | 2026 |
| Ambush Limited | Professional & scientific | 2021 |
| Amec (F.C.G.) Limited | Professional & scientific | 1917 |
| Amec (MH1992) Limited | Professional & scientific | 1927 |
| Amec (WSL) Limited | Extraterritorial | 1952 |
| Amec BKW Limited | Extraterritorial | 1920 |
| Amec Bravo Limited | Financial services | 2007 |
| Amec Building Limited | Professional & scientific | 1920 |
| Amec Capital Projects Limited | Extraterritorial | 1993 |
| Amec Civil Engineering Limited | Extraterritorial | 1976 |
| Amec Engineering Limited | Extraterritorial | 1962 |
| Amec Foster Wheeler (Holdings) Limited | Financial services | 1920 |
| Amec Foster Wheeler Energy Limited | Professional & scientific | 1978 |
| Amec Foster Wheeler Finance Asia Limited | Financial services | 2007 |
| Amec Foster Wheeler Finance Limited | Administrative & support | 1977 |
| Amec Foster Wheeler Group Limited | Administrative & support | 2002 |
| Amec Foster Wheeler International Limited | Mining & quarrying | 1996 |
| Amec Foster Wheeler Limited | Financial services | 1982 |
| Amec Investments Europe Limited | Financial services | 1999 |
| Amec Offshore Limited | Professional & scientific | 1972 |
| Amec Process and Energy Limited | Extraterritorial | 1986 |
| Amec Project Investments Uclh Limited Partnership | | 2004 |
| Amec Services Limited | Professional & scientific | 1993 |
| Amelia Knight (UKM) Limited | Manufacturing | 2023 |
| Amelia Knight Holdings Limited | Wholesale & retail | 2013 |
| Amelia Knight Limited | Manufacturing | 1995 |
| Americana Communications Ltd | Professional & scientific | 2024 |
| Amgolfapparel Ltd | Wholesale & retail | 2021 |
| Amplepaint Limited | Other services | 1995 |
| Ampura Ltd | Information & communication | 2002 |
| AMY Briers Architects Ltd | Professional & scientific | 2023 |
| Andco Studio Ltd | Professional & scientific | 2020 |
| Andrelle Limited | Information & communication | 2019 |
| Andrew Sellick Consulting Ltd | Professional & scientific | 2023 |
| Andy Hopkinson Limited | Construction | 2004 |
| Aneto Bridge ST Ltd | Real estate | 2022 |
| Aneto Developments Ltd | Construction | 2011 |
| Aneto Freeholdings Ltd | Real estate | 2020 |
| Aneto Properties Ltd | Real estate | 2018 |
| ANF Properties (Knutsford) Limited | Real estate | 2016 |
| Angelique Records Ltd | Arts & recreation | 2025 |
| Anglesey Capital Limited | Real estate | 2020 |
| ANN TEK IT Ltd | Information & communication | 2024 |
| Anna Marczynski Design Ltd | Information & communication | 2019 |