| Atech Holdings Limited | Financial services | 2025 |
| Atech Motor Solutions Limited | Wholesale & retail | 2011 |
| Atelier Collection Ltd | Professional & scientific | 2025 |
| Atelier Interior Design Ltd | Professional & scientific | 2015 |
| ATI Group Ltd | Information & communication | 2020 |
| Atiga Ltd | Real estate | 2021 |
| Atkinson Repairs Limited | Wholesale & retail | 2014 |
| Atlas Automobiles UK Ltd | Manufacturing | 2022 |
| Atlas Business Management Limited | Other services | 2005 |
| Atlas Motors Limited | Wholesale & retail | 2025 |
| Atlas Screeding Ltd | Construction | 2009 |
| Atria Interiors Limited | Professional & scientific | 2019 |
| Atriumcon Limited | Real estate | 2024 |
| Auction House Courtyard Residents Management Company Limited | Households | 2004 |
| Audit and Risk Consulting Ltd. | Professional & scientific | 2015 |
| Augment Systems Limited | Professional & scientific | 2014 |
| Auntie Janis's Ltd | Hospitality | 2022 |
| Aura Investment Property Ltd | Real estate | 2015 |
| Aurora Fortunae Ltd | Financial services | 2017 |
| Aurra Studios Limited | Information & communication | 2019 |
| Auspicio Limited | Professional & scientific | 2007 |
| Auto Avenue Ltd | Wholesale & retail | 2023 |
| Autoflyx Ltd | Wholesale & retail | 2025 |
| Auxillium Ltd | Professional & scientific | 2022 |
| AV Sovereign Ltd | Real estate | 2021 |
| AVA Money Limited | Information & communication | 2024 |
| Avery Weigh-Tronix Finance Limited | Professional & scientific | 2003 |
| Avery Weigh-Tronix International Limited | Financial services | 1894 |
| Aviation Transport Consultancy Services Limited | Transport & logistics | 2010 |
| AVN9 Limited | Financial services | 2016 |
| Avondale Consultancy Limited | Real estate | 2017 |
| Avts Consultancy Limited | Professional & scientific | 2010 |
| AW Car Solution Ltd | Wholesale & retail | 2025 |
| Awesome Trading Limited | Information & communication | 2020 |
| Axapro Consulting Limited | Information & communication | 2001 |
| Axiom Executive Limited | Administrative & support | 2019 |
| AZH Accountancy Ltd | Professional & scientific | 2023 |
| Azure Yacht Management Ltd | Other services | 2016 |
| B Aero Ltd | Manufacturing | 2025 |
| B Dezdari Construction Ltd | Construction | 2024 |
| B Healing Centre Ltd | Health & social care | 2019 |
| B Hodge Limited | Information & communication | 2025 |
| B S R Consultants Limited | Information & communication | 2010 |
| B&B London Property Ltd | Real estate | 2023 |
| B&D COX Ltd | Information & communication | 2025 |
| B&O Services Ltd | Wholesale & retail | 2021 |
| B.S Lighting Ltd | Construction | 2022 |
| Baan RAK Thai Ltd | Other services | 2026 |
| Babbling on Limited | Other services | 2014 |
| Babel Fish Consulting Limited | Professional & scientific | 2023 |
| Bacana Sangria UK Limited | Extraterritorial | 2018 |
| Baidwan Limited | Transport & logistics | 2008 |
| Bailrigg Capital Limited | Administrative & support | 2009 |
| Bajwa Corporation Ltd | Wholesale & retail | 2026 |
| Balls Pond Road Management Co Ltd | Real estate | 2021 |
| Balmoral Mews (Windsor) Management Company Limited | Real estate | 1988 |
| Bamotorco Ltd | Wholesale & retail | 2023 |
| Banana Split Records Ltd | Arts & recreation | 2019 |
| Bandgap Ltd | Professional & scientific | 2013 |
| Bandobras Ltd | Wholesale & retail | 2020 |
| Bankside Property Management Limited | Real estate | 1994 |
| Banoop Limited | Information & communication | 2012 |
| Bare Brilliance Ltd | Other services | 2021 |
| Barista Property Rentals Limited | Real estate | 2013 |
| Barnes IP Limited | Professional & scientific | 2016 |
| Barnes IP Training Limited | Education | 2019 |
| Baro Savel Ltd | Professional & scientific | 2026 |
| Barratt Sales and Lettings Limited | Construction | 2012 |
| Barrie Cornes Consulting Limited | Professional & scientific | 2020 |
| Bartoszek Limited | Construction | 2023 |
| Base Strength and Conditioning Limited | Arts & recreation | 2020 |
| Basepoint Limited Partnership | | 2003 |
| Bastide Holdings Ltd | Financial services | 2023 |
| Baxterbasics Limited | Information & communication | 2008 |
| Bazl Ltd | Professional & scientific | 2024 |
| Bazowie Limited | Professional & scientific | 2018 |
| BC Property Management Ltd | Administrative & support | 2016 |
| BCM Hotels Ltd | Administrative & support | 2017 |
| BE Bulletproof Limited | Administrative & support | 2013 |
| BE Human First Limited | Administrative & support | 2012 |
| Beacot Enterprises Ltd | Real estate | 2024 |
| Beanage Ltd | Information & communication | 2023 |
| Beat My Freight Quote Limited | Transport & logistics | 2009 |
| Beau Garden Landscapes Ltd | Administrative & support | 2018 |
| Beaulieu Affordable Housing Limited | Construction | 2008 |
| Beaulieu Homes South Ltd | Construction | 2012 |
| Beaulieu Land Consultancy Ltd | Construction | 2013 |
| Beaulieu Land Limited | Professional & scientific | 2022 |
| Beaulieu Strategic North London Limited | Construction | 2015 |
| Beaumont Investment Group Limited | Real estate | 2020 |
| Beaumont Legal Services Limited | Professional & scientific | 2015 |
| Beaumont Place Limited | Real estate | 2015 |
| Beaumore Place Limited | Households | 2019 |
| Beautifully Undressed Limited | Wholesale & retail | 2012 |
| Beauty & Spa Luxury Ltd | Other services | 2022 |
| Beauty Spot by Dani Limited | Other services | 2021 |
| Bebe 1 Limited | Hospitality | 2025 |
| Bebop Capital Ltd | Professional & scientific | 2018 |
| Bedrock Accounting Services Ltd | Professional & scientific | 2024 |
| Bee-Net Services Limited | Information & communication | 2014 |