| Altinnikoli@Marroccosrestaurant Limited | Hospitality | 2019 |
| Altitude Accounting Services Ltd | Professional & scientific | 2019 |
| Altitude Investments Ltd | Real estate | 2021 |
| Altitude Management Services Ltd | Real estate | 2021 |
| Altoria Construction Ltd | Construction | 2025 |
| Altoria Ltd | Real estate | 2024 |
| Altri Medical Ltd | Health & social care | 2023 |
| Aluna Estates Limited | Real estate | 2025 |
| Alverton Digital Services Ltd | Administrative & support | 2011 |
| Alveston Court Limited | Households | 1993 |
| Alvise Studios Ltd | Information & communication | 2023 |
| Always Outnumbered Never Outgunned Limited | Wholesale & retail | 2010 |
| Alyx Limited | Arts & recreation | 2020 |
| AM Advisory Solutions Ltd | Professional & scientific | 2025 |
| Amanat Consultancy Ltd | Other services | 2026 |
| Amandine Beke Ltd | Administrative & support | 2018 |
| Amanzi Music Ltd | Information & communication | 2026 |
| Amara Cleaning Ltd | Administrative & support | 2022 |
| Amarynthia Ltd | Professional & scientific | 2019 |
| Amazonia Brasil Limited | Wholesale & retail | 2020 |
| Ambassador Films Ltd | Information & communication | 2025 |
| Amber Court Hove RTM Company Limited | Households | 2010 |
| Amber's Office Ltd | Professional & scientific | 2019 |
| Amberley Court Management Company Limited | Households | 1989 |
| Amberley Hulme Wealth Management Limited | Financial services | 2018 |
| Ambex Limited | Manufacturing | 1974 |
| Ambiguous Authors Ltd | Information & communication | 2020 |
| AMC Brickwork Ltd | Construction | 2017 |
| AMC Group Enterprises Ltd | Financial services | 2020 |
| Amcuity LLP | | 2015 |
| Amdenta Ltd | Health & social care | 2023 |
| Ameliorate Consulting Limited | Professional & scientific | 2023 |
| American Cultural Organisation UK Limited | Education | 2009 |
| American Culture Collages Ltd | Education | 2023 |
| Amethyst Asset Investment Ltd | Real estate | 2023 |
| AMG Consult Ltd | Professional & scientific | 2017 |
| Amherst Properties Ltd | Real estate | 2019 |
| Amici Trattoria Hove Ltd | Hospitality | 2021 |
| Amir Property Maintenance Limited | Construction | 2008 |
| Amloc Limited | Households | 1990 |
| AMN Consulting Services Ltd | Administrative & support | 2024 |
| Amoa Limited | Financial services | 2010 |
| Amor Hair and Beauty Limited | Other services | 2020 |
| AMP Consulting Group Ltd | Information & communication | 2025 |
| Ampito Capital Limited | Professional & scientific | 2018 |
| Ampito Group LLP | | 2009 |
| Ampito Limited | Information & communication | 2005 |
| Ampito Options LLP | | 2012 |
| Ampito Sports Management LLP | | 2013 |
| Amplified Global Ltd | Information & communication | 2017 |
| Amplify C-Com Ltd | Professional & scientific | 2019 |
| AMR Healthcare Limited | Health & social care | 2021 |
| Amvima LLP | | 2013 |
| AMY Beth Dalla Mura Ltd | Extraterritorial | 2024 |
| AMY Dury Ltd | Arts & recreation | 2025 |
| AN Motorsport Limited | Manufacturing | 2006 |
| Anakim Ltd | Real estate | 2021 |
| Anaman Associates Limited | Health & social care | 2021 |
| Anark Ltd | Administrative & support | 2025 |
| Anatomy HCD Limited | Professional & scientific | 2012 |
| Anchorpoint Commerce Ltd | Wholesale & retail | 2025 |
| AND Create Limited | Professional & scientific | 2025 |
| Anders Pink Limited | Professional & scientific | 2014 |
| Anderson Haysom Design Ltd | Construction | 2023 |
| Andre Calvo Limited | Information & communication | 2018 |
| Andre Lichtenberg Photography Limited | Professional & scientific | 2015 |
| Andrew Barton Consultancy Services Limited | Other services | 2015 |
| Andrew Barton London Education Limited | Other services | 2018 |
| Andrew Barton Productions Limited | Other services | 2019 |
| Andrew Bonner Consulting Ltd | Information & communication | 2021 |
| Andrew Gidis Ltd | Health & social care | 2022 |
| Andrew Jukes Professional Services (Ajps) Limited | Professional & scientific | 2024 |
| Andrew Lynch Ltd | Professional & scientific | 2020 |
| Andrew Puddiford Psychology Limited | Education | 2024 |
| Andrew Turford & Co Limited | Other services | 2006 |
| Andromeda Capital Investments UK Ltd | Mining & quarrying | 2018 |
| Andy LO PÒ Ltd | Arts & recreation | 2011 |
| Andy Stone Bespoke Interiors Limited | Construction | 2012 |
| ANG Electrical Sussex Limited | Construction | 2024 |
| Angel FOX Ltd | Information & communication | 2024 |
| Angela Maccarthy Limited | Professional & scientific | 2012 |
| Angelcraft Ltd | Real estate | 2017 |
| Anglesey Solar Limited | Energy | 2013 |
| Anglo Asset Management LLP | | 2012 |
| Anglogrange Properties Limited | Real estate | 1996 |
| Anjin Games Ltd | Information & communication | 2015 |
| Anjul & Co. Holdings Ltd | Financial services | 2025 |
| Ankersen Inc Ltd | Professional & scientific | 2017 |
| Anna Billingham Limited | Hospitality | 2015 |
| Anna Cullum Limited | Professional & scientific | 2018 |
| Anna Nail and Hair Ltd | Other services | 2018 |
| Anna Stickland Ltd | Information & communication | 2013 |
| Annette Hawes Limited | Health & social care | 2025 |
| Annie and Janjan Ltd | Real estate | 2021 |
| Another Firm Ltd | Wholesale & retail | 2025 |
| Another Thought Limited | Administrative & support | 2022 |
| ANR Electrical Services Limited | Construction | 2017 |
| Anroe Electrical Limited | Construction | 2009 |
| Ansley Limited | Extraterritorial | 2000 |
| Anthony & Catherine Ltd | Transport & logistics | 2015 |