| Alton House Limited | Construction | 1983 |
| Altrico Limited | Information & communication | 2005 |
| Aluminium Gutter Systems Ltd | Wholesale & retail | 2002 |
| Alverium Health Limited | Professional & scientific | 2021 |
| Alverium Life Sciences Ltd | Professional & scientific | 2025 |
| Alverium Limited | Professional & scientific | 2021 |
| Ambershield Limited | Households | 1984 |
| Amberspeed Media Ltd | Information & communication | 2019 |
| Amethyst Education Ltd | Education | 2019 |
| AMG Building Limited | Construction | 2006 |
| Amjf Limited | Professional & scientific | 2017 |
| Amora Dog Care Ltd | Agriculture & fishing | 2024 |
| Ample Solutions Ltd | Administrative & support | 2021 |
| Amrose Entertainment Ltd | Information & communication | 2013 |
| AMY a Wright Ltd | Administrative & support | 2016 |
| Analuma Ltd | Financial services | 2016 |
| Ancestral Homes Limited | Extraterritorial | 1996 |
| Anco Solutions Ltd | Professional & scientific | 2017 |
| Anderson Wheeler Limited | Wholesale & retail | 2013 |
| Angel Education Tuition Ltd | Education | 2023 |
| Anglo German Consulting Ltd | Administrative & support | 2004 |
| Anna Heenan Consulting Ltd | Other services | 2018 |
| Anna-Marie Marshall Ltd | Professional & scientific | 2024 |
| Anstey Lane Management Limited | Real estate | 2021 |
| Ansvar House Leases Ltd | Real estate | 2025 |
| Antibes Holdings Limited | Construction | 2006 |
| Antill Media Limited | Information & communication | 2006 |
| ANY Roof Group Ltd | Construction | 2026 |
| Aoma OIL Ltd | Professional & scientific | 2022 |
| Apole Engineering Company Limited | Other services | 1965 |
| Apple Orchard Media Ltd | Professional & scientific | 2024 |
| Aquinella GP LLP | | 2024 |
| Aquinella Investments Limited | Financial services | 2023 |
| Aquinella Limited Partnership | | 2023 |
| Aquinella NO.1 Limited | Financial services | 2024 |
| AR England Limited | Arts & recreation | 2017 |
| Arbrook Investments Properties Limited | Real estate | 2009 |
| Arcadian Lifestyle Limited | Administrative & support | 2014 |
| Arcfyre UK Limited | Administrative & support | 2010 |
| Ardent Music Limited | Arts & recreation | 2003 |
| Ares Boxwear Limited | Wholesale & retail | 2024 |
| Argo Business Champions Limited | Professional & scientific | 2022 |
| Argo Business Compliance Limited | Professional & scientific | 2019 |
| Arian Investments Limited | Extraterritorial | 2015 |
| Arian Properties Limited | Real estate | 1996 |
| Aribo Estates Limited | Real estate | 2024 |
| Arma & Partners Ltd | Construction | 2017 |
| Arreton Developments Limited | Real estate | 2011 |
| Artarmon Ltd | Professional & scientific | 2010 |
| Artisan Pubs and Bars Ltd | Hospitality | 2024 |
| AS Projects (Epsom) Limited | Construction | 2012 |
| Ascend World Limited | Professional & scientific | 2013 |
| Ashlyn's Park Residents Association (Cobham) Limited | Extraterritorial | 1987 |
| Asian Women Mean Business Ltd | Education | 2021 |
| Aspen Motors Ltd | Wholesale & retail | 2019 |
| Associated Networks (UK) Limited | Information & communication | 2002 |
| AST Resources Limited | Financial services | 2025 |
| Astoria Limited | Real estate | 2021 |
| AT Sea Holdings Ltd | Financial services | 2026 |
| AT11 Limited | Arts & recreation | 2024 |
| Athena Property Holdings Limited | Real estate | 2020 |
| Atkins Communications Ltd | Professional & scientific | 2025 |
| ATS Construction Services Limited | Construction | 2017 |
| Aumentech Limited | Administrative & support | 2022 |
| Automotive Research Unit Limited | Information & communication | 1987 |
| Autonomyx Ltd | Information & communication | 2025 |
| Avalon Media Music Limited | Information & communication | 2023 |
| Avanii Ltd | Wholesale & retail | 2021 |
| Avarchie Ltd | Professional & scientific | 2014 |
| Avco Aviation Services Limited | Information & communication | 2024 |
| AVEE8 Aerial Intelligence Ltd | Professional & scientific | 2026 |
| Avelo Group Limited | Administrative & support | 2026 |
| Avenue Road Cobham Residents Association Limited | Households | 2001 |
| AVI Consulting Ltd | Professional & scientific | 2013 |
| AW Sports Promotions Ltd | Arts & recreation | 2024 |
| AWB Sports Ltd | Arts & recreation | 2018 |
| AWC Tech Ltd | Construction | 2013 |
| Awen Emotions Ltd | Information & communication | 2022 |
| AWM1982 Limited | Professional & scientific | 2022 |
| AWT Design and Build Ltd | Construction | 2021 |
| Axcess (UK) Limited | Extraterritorial | 2019 |
| AXE Group Limited | Construction | 2019 |
| Axel Tuanzebe Limited | Arts & recreation | 2015 |
| Aycel Consulting Ltd | Professional & scientific | 2014 |
| Aycel Ltd | Other services | 2015 |
| B.P. Estates (Contractors) Limited | Administrative & support | 2000 |
| B.P. Estates Limited | Real estate | 1997 |
| Baden Powell Properties Ltd | Real estate | 2020 |
| Bailey & Bailey Holdings Limited | Real estate | 2020 |
| Bamber Miller Architects Limited | Professional & scientific | 2010 |
| Bandb Transformations Limited | Financial services | 2026 |
| Banstead Developments Limited | Construction | 2007 |
| Bantour Limited | Arts & recreation | 2017 |
| Bardella Investments Limited | Real estate | 2021 |
| Barry Feltham Consultancy Limited | Other services | 2018 |
| Batprop Limited | Real estate | 2023 |
| Battersea Reach Estate Company Limited | Administrative & support | 2000 |
| BBM Consultancy Ltd | Professional & scientific | 2024 |
| BC TV Ltd | Information & communication | 2015 |
| Beacon Capital Advisory Solutions Ltd | Professional & scientific | 2022 |