| Ammanrec Limited | Information & communication | 2023 |
| Ammika Solutions Limited | Health & social care | 2021 |
| AMO Capital Limited | Real estate | 2023 |
| Amped UP Solutions Ltd | Wholesale & retail | 2025 |
| Ampika's Hair, Makeup and Beauty Studios Ltd | Other services | 2018 |
| Ampikas Academy Wholesale Ltd | Education | 2020 |
| Amplif-I Energy Ltd | Arts & recreation | 2024 |
| Ampode Limited | Manufacturing | 2018 |
| Ampol UK Holdings Limited | Financial services | 2025 |
| Ampol UK Trading Limited | Wholesale & retail | 2025 |
| Amro Technologies Limited | Professional & scientific | 2019 |
| Amsfield Design & Build Ltd | Construction | 2019 |
| Amstone Charitable Trust Limited | Professional & scientific | 2008 |
| Amstone Developments Limited | Real estate | 1989 |
| Amstone Kingsgate Limited | Administrative & support | 2017 |
| Amstone Property Management Limited | Real estate | 2011 |
| Amstone Ventures IV LLP | | 2020 |
| Amtoo Limited | Administrative & support | 2026 |
| AMW Contract Limited | Professional & scientific | 2017 |
| Amwell Limited | Professional & scientific | 2025 |
| AMX One Ltd | Real estate | 2020 |
| AMY Roberts Limited | Information & communication | 2012 |
| Amzi Holdings Limited | Administrative & support | 2017 |
| AN Experiment in Art Ltd | Education | 2022 |
| AN Tennis Coaching Ltd | Education | 2022 |
| Anaesthetically Pleasing Ltd | Health & social care | 2026 |
| Analemma Limited | Professional & scientific | 2024 |
| Analyzed Insights Limited | Information & communication | 2024 |
| Anam Alisha Limited | Wholesale & retail | 2018 |
| Anatomy Urban Retreat Limited | Other services | 2018 |
| Anchor 22 Consultancy Limited | Professional & scientific | 2026 |
| Anchor Point Advisors Limited | Professional & scientific | 2017 |
| Anchor Removals Limited | Transport & logistics | 2008 |
| Anchorage Investment | Financial services | 2017 |
| Anco Investments Limited | Real estate | 2020 |
| Ancyra Holdings Ltd | Financial services | 2026 |
| Ancyra IP Ltd | Administrative & support | 2026 |
| Ande.Ai Ltd | Information & communication | 2026 |
| Anderson Process Engineering Limited | Professional & scientific | 2009 |
| Andmore FD1 Limited | Real estate | 2025 |
| Andmore Fole Limited | Real estate | 2025 |
| Andmore Group Limited | Real estate | 2022 |
| Andmore Homes & Developments Limited | Construction | 2020 |
| Andmoreco Limited | Professional & scientific | 2013 |
| Andrew & Oaks Consulting Ltd | Information & communication | 2019 |
| Andrew Bruce Consulting Limited | Information & communication | 2017 |
| Andrew Cooke Limited | Hospitality | 2002 |
| Andrew Court Management Company Limited | Households | 1981 |
| Andrew Daldry Wealth Management Ltd | Financial services | 2013 |
| Andrew Daly HV Engineering Limited | Administrative & support | 2016 |
| Andrew Hart Ltd | Professional & scientific | 2014 |
| Andrew LEE Consulting Limited | Administrative & support | 2009 |
| Andrew Limbert Transport Limited | Transport & logistics | 2016 |
| Andrew Ryan Limited | Wholesale & retail | 2018 |
| Andrew Seldon Consultancy Ltd | Professional & scientific | 2024 |
| Andrew Smith Electrical Limited | Construction | 2006 |
| Andy Jennings Limited | Administrative & support | 2014 |
| Angela FOX Ltd | Other services | 2020 |
| Angela Oguns Limited | Professional & scientific | 2019 |
| Angels & Equity Limited | Administrative & support | 2005 |
| Angels Wing Limited | Professional & scientific | 2025 |
| Angelson Limited | Real estate | 2005 |
| Angelstar 2000 Limited | Arts & recreation | 1999 |
| Anglo Sard Limited | Professional & scientific | 2023 |
| Angus Land Company Limited | Real estate | 2024 |
| Anibild Studio Ltd | Information & communication | 2026 |
| Anil J Ventures Ltd | Financial services | 2021 |
| Animal Best Friends | Health & social care | 2018 |
| Animation Toolkit Ltd | Wholesale & retail | 2011 |
| Anita Watson Consulting Ltd | Professional & scientific | 2025 |
| ANJ ERP Services Limited | Information & communication | 2025 |
| Anj.N. Consulting Limited | Professional & scientific | 2026 |
| Anjaneya Real Estate Ltd | Real estate | 2020 |
| ANN Tyler Holidays Lets Limited | Real estate | 2023 |
| Anna Cullen Limited | Professional & scientific | 2023 |
| Anna Hudson Hair Ltd | Other services | 2026 |
| Annabel English Marketing Ltd | Professional & scientific | 2021 |
| Annapurna Paakashala Limited | Hospitality | 2024 |
| Anne Humphris Limited | Information & communication | 2012 |
| Anneco Cleaning Services Limited | Other services | 2019 |
| Anni Nilsson Limited | Manufacturing | 2020 |
| Another Space Property Ltd | Real estate | 2020 |
| Another.Com Limited | Information & communication | 1998 |
| Ansira Partners Ltd. | Professional & scientific | 2021 |
| Ansl Medical Ltd | Health & social care | 2026 |
| Anslow Building Surveyors Limited | Professional & scientific | 2024 |
| Antares Capital London Limited | Financial services | 2023 |
| Anterior Holdings Ltd | Financial services | 2024 |
| Anthem Lettings and Consultancy Limited | Real estate | 2014 |
| Anthony Horne Licensing Limited | Professional & scientific | 2010 |
| Anthony J. Limited | Other services | 2003 |
| Anthony Lyons Consulting Limited | Professional & scientific | 2022 |
| Anti-Flood Systems Limited | Wholesale & retail | 2011 |
| Anticimex UK Holding Limited | Professional & scientific | 2022 |
| Antspin Limited | Administrative & support | 2010 |
| Antz in Your Pantz Ltd | Arts & recreation | 2020 |
| Anubis KIT Limited | Real estate | 2004 |
| Anusha Medical Services Limited | Health & social care | 2010 |
| Anyar Limited | Administrative & support | 2019 |
| AOE Properties Limited | Real estate | 2023 |