| Atelier LE Grand Village Limited | Arts & recreation | 2020 |
| Atelier Zeta Ltd | Administrative & support | 2021 |
| Athena AI Technologies Limited | Information & communication | 2023 |
| Athena Close Block a Freehold Company Limited | Households | 2013 |
| Athena Trade Limited | Information & communication | 2023 |
| Atheray Stone Ltd | Administrative & support | 2019 |
| Athlete London Limited | Arts & recreation | 2009 |
| ATI Falcons Ltd | Professional & scientific | 2025 |
| Atlantean Limited | Professional & scientific | 2023 |
| Atlantic UK Logistics Ltd | Transport & logistics | 2008 |
| Atlas Business Services Limited | Professional & scientific | 1996 |
| Atlas Corporate Secretaries Limited | Other services | 2000 |
| Atrium Godalming RTM Company Limited | Administrative & support | 2008 |
| Atrium Management Limited | Real estate | 2009 |
| ATS Compliance Limited | Extraterritorial | 2015 |
| Attimo Energy Ltd | Wholesale & retail | 2024 |
| Attimo Investments Ltd | Real estate | 2023 |
| Attimo Ltd | Construction | 2017 |
| Attiya Beauty Studio Ltd | Other services | 2024 |
| Attribute Consulting Group Limited | Information & communication | 2016 |
| Audi Motorsport Technology Centre UK Limited | Professional & scientific | 2024 |
| Audience Engagement UK Limited | Professional & scientific | 2017 |
| Audiocultureuk Ltd | Wholesale & retail | 2023 |
| Auditel (U.K.) Limited | Professional & scientific | 1994 |
| Auditel Consulting Limited | Extraterritorial | 2002 |
| Auditel Limited | Extraterritorial | 2007 |
| Augmented World Limited | Professional & scientific | 2014 |
| Augustine Oliver Ltd | Administrative & support | 2025 |
| Auignon Limited | Households | 1999 |
| AUM Beloved Light Limited | Financial services | 2011 |
| Aura Grid Energy Ltd | Energy | 2026 |
| Aura Marketing and Events Limited | Professional & scientific | 2023 |
| Auran Consulting Ltd | Professional & scientific | 2025 |
| Aurora Club Limited | Other services | 2025 |
| Ausbrands Ltd | Wholesale & retail | 2025 |
| Austin Quality Associates Ltd | Professional & scientific | 2023 |
| Auto Amor Ltd | Wholesale & retail | 2025 |
| Automated Delivery Solutions Ltd | Information & communication | 2015 |
| Automated Process & Control Mfng. Co. Limited | Manufacturing | 1967 |
| Autumn Commercial Properties Ltd | Real estate | 2025 |
| AV Drylining Limited | Construction | 2019 |
| AV Vehicle Leasing Limited | Administrative & support | 2022 |
| Avalesta Technology Ltd | Information & communication | 2016 |
| Avalvisa Ltd | Professional & scientific | 2025 |
| Avaqor Technologies UK Ltd | Information & communication | 2024 |
| Avedo (UK) Limited | Information & communication | 2001 |
| AVH Consulting Ltd | Professional & scientific | 2019 |
| Avinsys Ltd | Professional & scientific | 2017 |
| AVN Accounting Ltd | Professional & scientific | 2018 |
| AVO Digital Ltd | Information & communication | 2019 |
| Avon Seeds Ltd | Real estate | 2021 |
| Awake Services Limited | Information & communication | 2007 |
| Away Days Media Ltd | Information & communication | 2017 |
| Awesome Grill Ltd | Hospitality | 2018 |
| AWM Consulting Limited | Professional & scientific | 2017 |
| Axian Capital Management Limited | Financial services | 2020 |
| AXK Consultancy Limited | Education | 2021 |
| Axon Lake Ltd. | Professional & scientific | 2025 |
| Axys Group Limited | Construction | 2024 |
| Ayaadi Consulting Ltd | Professional & scientific | 2021 |
| Ayaan Car Wash Ltd | Wholesale & retail | 2023 |
| Aycan Hardy Beauty Aesthetic Ltd | Health & social care | 2023 |
| Ayny Car Wash Ltd | Administrative & support | 2025 |
| AYR Burdekin Limited | Information & communication | 2015 |
| Ayurveda Health Limited | Health & social care | 2019 |
| Azhang Studio Ltd | Wholesale & retail | 2026 |
| Azina Projects Limited | Professional & scientific | 2015 |
| Aztec E-Commerce Investments Limited | Wholesale & retail | 2021 |
| Azure Build Works Ltd | Construction | 2023 |
| Azure Communications UK Limited | Manufacturing | 2020 |
| Azuros Limited | Professional & scientific | 2024 |
| Azzaman International Limited | Information & communication | 2002 |
| Azzofera Limited | Financial services | 2012 |
| B & C Niche Wines Limited | Professional & scientific | 2013 |
| B and M Carpets & Flooring Ltd | Wholesale & retail | 2026 |
| B for Bravo Limited | Professional & scientific | 2015 |
| B Girl Fashions Ltd | Wholesale & retail | 2009 |
| B Linked Consultancy Limited | Professional & scientific | 2024 |
| B M Superstores UK Limited | Wholesale & retail | 2016 |
| B33HOME Ltd | Construction | 2017 |
| Babyfoam UK Ltd | Professional & scientific | 2020 |
| Baccarat Trade LLP | | 2023 |
| Bach & Law Ltd | Professional & scientific | 2019 |
| Bachan Limited | Information & communication | 2015 |
| Back to Balance Healthcare Group Ltd | Health & social care | 2022 |
| Badgers Court Residents Association Limited | Households | 1976 |
| Bagcheck UK Limited | Transport & logistics | 2024 |
| BAI Tech Consulting Limited | Information & communication | 2021 |
| Bailey Mellon Ltd | Construction | 2018 |
| Baixin(Britain) Limited | Information & communication | 2024 |
| Balancing ACT Audio Ltd | Information & communication | 2011 |
| Balancing ACT Films Ltd | Information & communication | 2014 |
| Balans Investment Ltd | Real estate | 2023 |
| Ballantyne I. T. Limited | Information & communication | 2015 |
| Balletboyz Ltd | Arts & recreation | 2000 |
| Ballucci Limited | Hospitality | 2016 |
| Balmaire Limited | Wholesale & retail | 2026 |
| Baloolah TOO Limited | Wholesale & retail | 2024 |
| BAM Advisory Ltd | Professional & scientific | 2026 |
| Bambine Ltd | Information & communication | 2024 |