| Amaa Logistics Ltd | Transport & logistics | 2025 |
| Amanda Middleton Ltd | Education | 2023 |
| Amasys Ltd | Information & communication | 2000 |
| Amateur Darts Organisation Ltd | Arts & recreation | 2024 |
| Amazing Electricians Limited | Construction | 2018 |
| Amazing Investment Properties Ltd | Real estate | 2023 |
| Ambaline Ltd | Transport & logistics | 2019 |
| Ambion Contractors & Firewood Limited | Wholesale & retail | 2020 |
| Amcast Limited | Manufacturing | 1991 |
| AMG Contractors Ltd | Transport & logistics | 2021 |
| AMG Films Limited | Information & communication | 2015 |
| AMK Technology Ltd | Information & communication | 2025 |
| Ammr Ltd | Transport & logistics | 2017 |
| Amnad Ltd | Real estate | 2019 |
| Amor Holistic Healing Ltd | Health & social care | 2023 |
| Amore G.N.A. Limited | Wholesale & retail | 2016 |
| Amos Stoves & Building Services Ltd | Construction | 2026 |
| Ampletop Limited | Households | 1986 |
| Amplexus Solutions Limited | Information & communication | 2012 |
| Amrita Limited | Hospitality | 2006 |
| AMS Farming Limited | Agriculture & fishing | 2026 |
| AMS Garden Services Ltd | Administrative & support | 2020 |
| Amtrak Logistics Ltd | Transport & logistics | 2014 |
| AMX29 Services Ltd | Manufacturing | 2010 |
| AN Patel Limited | Wholesale & retail | 2021 |
| Anandi Veer Holdings Ltd | Real estate | 2023 |
| Anaram Investments Ltd | Real estate | 2024 |
| Anaso Property Holdings Ltd | Real estate | 2026 |
| Anchor Event Management Ltd | Hospitality | 2022 |
| Anchor Event Services Ltd | Hospitality | 2025 |
| Anderson Personnel Limited | Administrative & support | 2011 |
| Andmar Machinery Services Limited | Manufacturing | 1984 |
| Andomar Haulage Ltd | Transport & logistics | 2023 |
| Andreas Transport Limited | Administrative & support | 2019 |
| Andrew Bubb Professional Kitchen Installer Ltd | Construction | 2007 |
| Andrew Langley Ltd | Arts & recreation | 2011 |
| Andrew Paul Hipkiss Limited | Extraterritorial | 2024 |
| Andrew Rose Holdings Limited | Financial services | 2022 |
| Andrewjmb Limited | Transport & logistics | 2017 |
| ANE Electronics Ltd | Manufacturing | 2021 |
| Angel and Star Care Services Ltd. | Administrative & support | 2018 |
| Angel Calibre Care Ltd | Health & social care | 2019 |
| Angela.Brown Ltd | Administrative & support | 2022 |
| Anglobras Limited | Extraterritorial | 2012 |
| Angry Alien Limited | Information & communication | 2009 |
| Angy International Ltd | Transport & logistics | 2018 |
| Animaltopia Ltd | Wholesale & retail | 2025 |
| Anison Healthcare Services Ltd | Health & social care | 2023 |
| Anker Elemental Limited | Professional & scientific | 2016 |
| Anker Holdings Ltd | Real estate | 2008 |
| Anker Valley Canoe Club Limited | Arts & recreation | 1987 |
| Anna Gibiino Trading AS Mould Doctor Midlands Ltd | Construction | 2022 |
| Anna GUY Holdings Limited | Real estate | 1972 |
| Anne Stokes Collection Limited | Arts & recreation | 2011 |
| Anne-Marie Blewitt Consulting Ltd | Education | 2020 |
| Ano.S. Consultancy Ltd | Public administration | 2025 |
| Ansiti Property Ltd | Real estate | 2025 |
| Ansley Hall Management Company Limited | Households | 1999 |
| Ansley Motor Company Ltd | Wholesale & retail | 2025 |
| ANT Logistics Exhibition Services Ltd | Transport & logistics | 2015 |
| Anthony Pullen Personal Training Ltd | Arts & recreation | 2019 |
| Anthony's Catering Ltd | Hospitality | 2015 |
| Anti-Crime Security Services Limited | Professional & scientific | 2002 |
| ANU & ABI Ltd | Wholesale & retail | 2021 |
| ANYGOLDENGIRL4YOU Limited | Administrative & support | 2022 |
| Anything U Want Limited | Administrative & support | 2006 |
| Aocg Transport Limited | Transport & logistics | 2025 |
| AP 2011 Limited | Construction | 2011 |
| AP Property Investments & Holdings Ltd | Real estate | 2020 |
| AP4 Properties Ltd | Real estate | 2022 |
| Apex Automotive Solutions Ltd | Wholesale & retail | 2024 |
| Apex Carpentry & Joinery Limited | Construction | 2018 |
| Apex Scale Ltd | Information & communication | 2026 |
| Apex Stay Solutions Ltd | Real estate | 2026 |
| Apex Timber Engineering Limited | Manufacturing | 2023 |
| Apex Venture Group Ltd | Real estate | 2022 |
| APK Property Investment Ltd | Real estate | 2023 |
| Apollo Construction & Groundworks Limited | Construction | 2025 |
| Appcraft-G Ltd | Information & communication | 2025 |
| Applebite Ltd | Real estate | 2016 |
| Applewood Support Limited | Health & social care | 2008 |
| Appliance Valeting Service Limited | Administrative & support | 2019 |
| Approach Education Ltd | Education | 2022 |
| Approved Performance UK Ltd | Administrative & support | 2017 |
| APR Supply Chain Solutions Ltd | Information & communication | 2014 |
| Apra Real Estate Ltd | Real estate | 2021 |
| AQM Spinning Limited | Manufacturing | 2012 |
| Aquate Limited | Agriculture & fishing | 2026 |
| AR Elite Homes Ltd | Real estate | 2025 |
| ARA Property Solutions Limited | Construction | 2013 |
| Arbalice Limited | Professional & scientific | 1954 |
| Arbury Coachworks Limited | Wholesale & retail | 1986 |
| Arbury Composites Ltd | Manufacturing | 2025 |
| Arbury Court Management Company Limited | Professional & scientific | 2006 |
| Arbury Gates and Railings Ltd | Manufacturing | 2021 |
| Arbury Holdings Ltd | Administrative & support | 2021 |
| Arbury Installations Ltd | Manufacturing | 2024 |
| Arbury Takeaway Ltd | Hospitality | 2026 |
| Arbury Tools & Equipment Limited | Manufacturing | 1962 |
| Archer Accounts Ltd | Professional & scientific | 2023 |