| Automotive Exposure Limited | Other services | 2011 |
| Auxesia Limited | Professional & scientific | 2023 |
| Avenir Enterprises Limited | Information & communication | 2002 |
| Aventurine Plus Ltd | Construction | 2022 |
| Avenue West Abode Ltd | Construction | 2023 |
| Avijol Technologies Ltd | Information & communication | 2018 |
| Avish Limited | Administrative & support | 2010 |
| AW Edwards Property Limited | Real estate | 2019 |
| Awan London Ltd | Health & social care | 2025 |
| Awindigital Consulting Limited | Information & communication | 2024 |
| Axbz&Co Electrical Ltd | Construction | 2023 |
| Axel Throws Ltd | Arts & recreation | 2023 |
| Axsteria Limited | Information & communication | 2026 |
| Ayaan Tech Ltd | Wholesale & retail | 2025 |
| Ayrs Properties Ltd | Real estate | 2020 |
| AZ Advisors Limited | Professional & scientific | 2020 |
| AZ10 London Ltd | Real estate | 2023 |
| Azbuka Foundation | Education | 2013 |
| Azen Food Ltd | Wholesale & retail | 2020 |
| AZH Global Ltd | Administrative & support | 2025 |
| AZH1 Limited Limited | Education | 2024 |
| Azsl Limited | Information & communication | 2013 |
| Aztec Engineering UK Limited | Extraterritorial | 2000 |
| Azure Gold Ltd | Information & communication | 2007 |
| Aïelead Ltd | Education | 2025 |
| B & I Tours Limited | Transport & logistics | 2024 |
| B & P Enterprises Limited | Wholesale & retail | 2005 |
| B L a Mechanics Ltd | Wholesale & retail | 2020 |
| B S Joseph Consulting Limited | Information & communication | 2011 |
| B T Consultancy Limited | Information & communication | 2011 |
| B&K Luxury Furnishings Ltd | Wholesale & retail | 2026 |
| B.E.L Project Ltd | Construction | 2018 |
| B.J.R. Publishing Limited | Information & communication | 1989 |
| B.Lucille Ltd | Manufacturing | 2024 |
| B.R GAS Utilities Ltd | Construction | 2018 |
| B.R.G. Cucina Italiana Ltd | Hospitality | 2025 |
| B07 Couriers Ltd | Transport & logistics | 2015 |
| B7 Construction Ltd | Construction | 2020 |
| Babel Gift Ltd | Manufacturing | 2018 |
| Babette Limited | Professional & scientific | 2023 |
| Babies Unboxed Ltd. | Education | 2022 |
| Baby Health Box Ltd | Wholesale & retail | 2026 |
| Bada Bar Ltd | Extraterritorial | 2017 |
| Baharash Electrical Contractor Ltd | Manufacturing | 2024 |
| BAK Family Wines Limited | Wholesale & retail | 2018 |
| Baked Goods Records Ltd | Information & communication | 2022 |
| Bakubang Limited | Professional & scientific | 2006 |
| Bali Consulting Services Limited | Information & communication | 2016 |
| Ball Events Ltd | Hospitality | 2008 |
| Ballaro London Ltd | Hospitality | 2016 |
| Bamboo Rise Ltd | Extraterritorial | 2023 |
| Bambu 283 Waldegrave Road Limited | Real estate | 2010 |
| Bami Viet Limited | Hospitality | 2019 |
| Bana Homes Ltd | Construction | 2013 |
| Banda & Day Ltd | Transport & logistics | 2023 |
| Baneberry Finance Limited | Financial services | 2010 |
| Banyan Management Ltd | Real estate | 2024 |
| Baran Ltd | Manufacturing | 2023 |
| Baraqah Capital Ltd | Real estate | 2025 |
| Barkridges London Ltd | Wholesale & retail | 2022 |
| Barnes DRY Cleaners Limited | Other services | 2017 |
| Barons CUT Ltd | Other services | 2018 |
| Barons Villas Limited(The) | Hospitality | 1974 |
| Barre Collective Limited | Arts & recreation | 2021 |
| Barton Court Care Home Limited | Health & social care | 2017 |
| Base Media Cloud Limited | Information & communication | 2014 |
| BASE27 Labs Ltd | Information & communication | 2025 |
| Baseri Oxford Ltd | Other services | 2018 |
| Bassi Recruitments Limited | Administrative & support | 2025 |
| Bath Road One Limited | Real estate | 2025 |
| Bathe Bathrooms Limited | Construction | 2010 |
| Baumlink Ltd. | Information & communication | 2015 |
| Bay Tree Green Limited | Real estate | 2008 |
| Baydar Trade and Consulting Ltd | Professional & scientific | 2017 |
| Bayercastle Limited | Households | 1990 |
| Baylis Mews Residents Association Limited | Administrative & support | 2001 |
| Bazil & Ruby Animal Empire and Boutique Limited | Wholesale & retail | 2017 |
| BB Clinics Limited | Other services | 2025 |
| BB Podiatry Ltd | Health & social care | 2017 |
| BB Richmond Limited | Financial services | 2025 |
| Bbwventures Ltd | Agriculture & fishing | 2020 |
| Bcomp 291 Limited | Professional & scientific | 2006 |
| BE Frank Ltd | Professional & scientific | 2019 |
| BE Hunted Design Ltd | Professional & scientific | 2019 |
| BE More Gardener Ltd | Wholesale & retail | 2022 |
| BE True Sustainability Communications Ltd | Professional & scientific | 2021 |
| BE Vibrant Limited | Administrative & support | 2026 |
| BE With IT Ltd | Extraterritorial | 2021 |
| Beach Mission Ltd | Hospitality | 2024 |
| Beacon Hill Partners Limited | Professional & scientific | 2024 |
| Beans & Greens Ltd | Hospitality | 2016 |
| Bear Bear CHE Ltd | Wholesale & retail | 2025 |
| Bearfoot Consultants Ltd | Wholesale & retail | 2014 |
| Beaucare Limited | Other services | 2024 |
| Beauport Enterprises Limited | Administrative & support | 2008 |
| Beautiful Gardens Limited | Wholesale & retail | 2000 |
| Beautiful World London Ltd | Other services | 2015 |
| Beauty Haven Twickenham Ltd | Wholesale & retail | 2024 |
| Bebolt & Longfield Limited | Professional & scientific | 2023 |
| Bedford ROW Estates Limited | Other services | 2010 |