| Adwileyuk Investment Limited | Health & social care | 2016 |
| AED Training Ltd | Education | 2024 |
| Aero Metals Alliance UK Limited | Professional & scientific | 2014 |
| Aerotight Manufacturing Limited | Professional & scientific | 2005 |
| AF Canopy Ltd | Manufacturing | 2022 |
| AF Ventilation Ltd | Manufacturing | 2022 |
| Afayi Property Ltd | Real estate | 2024 |
| AFG4N 2 Ltd | Wholesale & retail | 2025 |
| AG Harmony Care Limited | Health & social care | 2025 |
| Agileup Limited | Extraterritorial | 2022 |
| Agility Logistics Limited | Transport & logistics | 2025 |
| Aglo Ltd | Transport & logistics | 2018 |
| AH Architectural Services (UK) Limited | Professional & scientific | 2015 |
| AHL Limited | Construction | 2015 |
| Ahmed & Sons Property Limited | Real estate | 2025 |
| AI Corporate Limited | Information & communication | 2016 |
| Air Diffusion Limited | Professional & scientific | 1973 |
| Air Engineering Solutions Limited | Energy | 1999 |
| Air Fresh Ltd | Other services | 2015 |
| Airocastle Limited | Administrative & support | 1983 |
| Airport Action Ltd | Information & communication | 2024 |
| AIS Shares Ltd | Wholesale & retail | 2025 |
| AIS Stakes Ltd | Wholesale & retail | 2025 |
| AJD Transportation Ltd | Transport & logistics | 2025 |
| Ajeet Capital Ltd | Health & social care | 2025 |
| AJS Colour Creations Ltd | Extraterritorial | 2025 |
| AJS Heating Ltd | Construction | 2022 |
| AJS Security Services Ltd | Administrative & support | 2021 |
| AK Papers Company Ltd | Manufacturing | 2019 |
| AK Services Midlands Ltd | Professional & scientific | 2018 |
| Akrofam Ltd | Real estate | 2021 |
| Akumen Business Consultancy Ltd | Administrative & support | 2015 |
| AL Barakah UK Holdings Ltd | Wholesale & retail | 2016 |
| AL Medina Bakers Limited | Wholesale & retail | 2025 |
| AL Shesha Limited | Wholesale & retail | 2019 |
| AL Siddique Best Trade Zone Ltd | Agriculture & fishing | 2026 |
| Alan Davies & SON Limited | Water & waste | 2000 |
| Albin Transport Limited | Transport & logistics | 2015 |
| Alethalbeetogerac.Com Limited | Wholesale & retail | 2025 |
| Alex Quality Ltd | Construction | 2013 |
| ALK Property Services WM Ltd | Real estate | 2025 |
| ALL 4 Heating & GAS Limited | Construction | 2019 |
| ALL Active Refreshments Ltd | Hospitality | 2010 |
| ALL Clear Services Limited | Water & waste | 2009 |
| ALL Routes Logistics Ltd | Transport & logistics | 2025 |
| ALL Star Sports Coaching CIC | Education | 2021 |
| ALL Steel Fencing Nationwide Ltd | Manufacturing | 2021 |
| ALL Steel Fencing Supplies Ltd | Manufacturing | 2024 |
| Allerton Plant & Ground Works Services Ltd | Construction | 2022 |
| Alliance UK Transportation Limited | Transport & logistics | 2025 |
| Aloona Ltd | Water & waste | 2026 |
| Alphalite Controls Ltd | Construction | 2022 |
| Alsoma Bushbury Limited | Other services | 2015 |
| Alternative Health Webinars Ltd | Education | 2019 |
| Alucast Group Limited | Manufacturing | 1994 |
| Aluminium Developments Group Limited | Professional & scientific | 2016 |
| Aluminium Shapes Limited | Manufacturing | 2000 |
| Alwins Authentic Jerk Products Limited | Manufacturing | 2010 |
| AM Auto Sales Ltd | Wholesale & retail | 2021 |
| Amally Ltd | Health & social care | 2022 |
| Amalma Limited | Real estate | 2024 |
| Amanah Capital Investments Limited | Real estate | 2025 |
| Amanya's Food Ltd | Hospitality | 2022 |
| Amari Central Services Ltd | Professional & scientific | 2023 |
| Amari Copper Alloys Limited | Wholesale & retail | 2010 |
| Amari Heritage Ltd. | Wholesale & retail | 2015 |
| Amari Metals China Limited | Wholesale & retail | 2007 |
| Amari Metals DC Pension Trustees Limited | Professional & scientific | 2003 |
| Amari Metals Engineering Group Limited | Manufacturing | 2022 |
| Amari Metals Limited | Professional & scientific | 1986 |
| Amari Metals Pension Trustees Limited | Professional & scientific | 1998 |
| Amari Precision Tubes Limited | Manufacturing | 2010 |
| Amario's Limited | Other services | 2010 |
| Amazing Bargainz Ltd | Wholesale & retail | 2025 |
| Amazingtech Ltd | Information & communication | 2025 |
| Amazoncool Limited | Transport & logistics | 2026 |
| Amber Alert Limited | Administrative & support | 2025 |
| Amber Home Developments Ltd | Construction | 2022 |
| Ameg Limited | Manufacturing | 2022 |
| Ameg Propco Ltd | Real estate | 2024 |
| Amelle Rawa Interiors Ltd | Wholesale & retail | 2026 |
| Amgk Limited | Construction | 2026 |
| Amigo Burgers Ltd | Hospitality | 2024 |
| Amolak Ltd | Real estate | 2025 |
| AMP Assets Ltd | Wholesale & retail | 2020 |
| AMP Capital Ltd | Real estate | 2025 |
| AMR Carpentry Ltd | Construction | 2019 |
| Amtech Range Limited | Manufacturing | 2009 |
| Anaya’S Salon Ltd | Other services | 2025 |
| Ancient Sands Limited | Wholesale & retail | 2024 |
| Andrew Dale Consultancy Services Ltd | Administrative & support | 2016 |
| Andrews Air Conditioning and Refrigeration Limited | Manufacturing | 1980 |
| Andrews Sykes Group PLC | Financial services | 1921 |
| Andrews Sykes Hire Limited | Wholesale & retail | 1994 |
| Andrews Sykes Hire Saudi Limited | Financial services | 2024 |
| Andrews Sykes International Limited | Financial services | 1968 |
| Andrews Sykes Properties Limited | Real estate | 1995 |
| Ang-Uk Entertainments Promotion Ltd | Hospitality | 2014 |
| Angel Remy Ltd | Wholesale & retail | 2014 |
| Angels Walsall Ltd | Real estate | 2025 |