| Blueway Limited | Information & communication | 2013 |
| Bluewood Consulting Limited | Professional & scientific | 2017 |
| Blueyellow Contracting Ltd | Administrative & support | 2019 |
| Bluezone Performance Ltd | Public administration | 2025 |
| Blu’S Flat Roofing Specialists Ltd | Construction | 2025 |
| BM Bosscat Homes Ltd | Households | 2025 |
| BM Cars Watford Ltd | Wholesale & retail | 2019 |
| BM96 Services Limited | Other services | 2026 |
| BMA Bespoke Cars Limited | Wholesale & retail | 2022 |
| BMA Bespoke Properties Ltd | Real estate | 2026 |
| BMA Rail Limited | Construction | 2016 |
| BMB Enterprises Ltd | Information & communication | 2018 |
| Bmdb Limited | Construction | 2015 |
| Bmem Treasury Ltd | Professional & scientific | 2019 |
| BMS BTC Ventures Ltd | Other services | 2025 |
| BMS Building & Groundworks Ltd | Construction | 2025 |
| BMS Corporate Holdings Ltd | Financial services | 2024 |
| BMS Fiduciary Services Limited | Administrative & support | 2010 |
| BMS Landscaping & Paving Ltd | Construction | 2021 |
| BMZ Rentals Limited | Real estate | 2019 |
| BN Consulting Ltd | Information & communication | 2025 |
| BNB Consultancy Ltd | Professional & scientific | 2018 |
| BNM Analytics Ltd | Professional & scientific | 2015 |
| Bnrl Limited | Health & social care | 2015 |
| BNS Solutions Limited | Information & communication | 2012 |
| BO Hari & T Ltd | Professional & scientific | 2025 |
| Boad Engineering Services Ltd | Professional & scientific | 2024 |
| Boad Management Services Ltd | Construction | 2022 |
| Bob's Bits Limited | Information & communication | 2016 |
| Boba Stop Ltd | Hospitality | 2026 |
| Boban & Sons Ltd | Construction | 2014 |
| Boban MV Ltd | Real estate | 2021 |
| Bobfix Ltd | Construction | 2025 |
| Bob’S Bits Holdings Limited | Financial services | 2022 |
| Bodet Time Limited | Information & communication | 1990 |
| Bodicraft Supplies Limited | Wholesale & retail | 2014 |
| Body B Limited | Other services | 2022 |
| Body+Beyond Ltd | Other services | 2017 |
| Bodyclinique Ltd | Health & social care | 2014 |
| Bogdan Vasilescu Haulage Ltd | Transport & logistics | 2019 |
| Bogl Construction Ltd | Construction | 2022 |
| Bohemian Pictures Ltd | Extraterritorial | 2009 |
| Bohola Inns Limited | Real estate | 2018 |
| Boiler in a Box Limited | Professional & scientific | 2017 |
| Boka Commercials Ltd | Transport & logistics | 2026 |
| Bokusashi Ltd | Information & communication | 2020 |
| Bold Over Property Limited | Real estate | 2025 |
| Bold Over Retail Limited | Wholesale & retail | 2021 |
| Bold Space Limited | Information & communication | 2019 |
| Bollywood Bites Limited | Hospitality | 2024 |
| Boltstand Limited | Real estate | 2003 |
| Bombay Jungle Ltd | Hospitality | 2019 |
| Bombay Wharf Management Limited | Households | 2002 |
| Bombon International Limited | Financial services | 2025 |
| Bonanza Spirits Ltd | Wholesale & retail | 2022 |
| Bondelega Ltd | Wholesale & retail | 2020 |
| Bondhill Limited | Real estate | 1997 |
| Bonfree London Ltd | Wholesale & retail | 2026 |
| Bonham Freeholds Limited | Construction | 2019 |
| Bonjet LP | | 2017 |
| Bonnybond Limited | Construction | 1986 |
| Bonours Ltd | Professional & scientific | 2024 |
| Bonsu Afro Shop Limited | Hospitality | 2023 |
| Bonum Team Ltd | Manufacturing | 2018 |
| Bonwin Construction Ltd | Construction | 2022 |
| Bonzanini Consulting Ltd | Information & communication | 2015 |
| Booboo Plant Hire Limited | Real estate | 2016 |
| Bookbuild Accountancy Ltd | Professional & scientific | 2008 |
| Books 2 Balance Ltd | Professional & scientific | 2014 |
| Bookwagon Limited | Wholesale & retail | 2017 |
| Boom Power Sports Ltd | Wholesale & retail | 2021 |
| Boomer's Adstock Investments Limited | Real estate | 2021 |
| Booming Numbers Ltd | Professional & scientific | 2021 |
| Boost My Customers Ltd | Professional & scientific | 2016 |
| Bootyfit Weight Loss Club Ltd | Arts & recreation | 2022 |
| Bordan Alliance Ltd. | Wholesale & retail | 2016 |
| Boreham Holt Residents Limited | Real estate | 1963 |
| Borghese Homes Limited | Real estate | 2024 |
| Boring Panda Ltd | Wholesale & retail | 2023 |
| Borlace Management Limited | Professional & scientific | 1989 |
| Borlase Property Management Ltd | Real estate | 2017 |
| Borough Projects Ltd | Financial services | 2005 |
| BOS. UK Limited | Administrative & support | 2000 |
| Boschman Limited | Administrative & support | 2018 |
| Bossa Shoes Limited | Manufacturing | 2023 |
| Boston Express Limited | Hospitality | 2005 |
| Botanico Vida Skincare Ltd | Wholesale & retail | 2022 |
| Botanix Ltd | Agriculture & fishing | 2025 |
| Botes Systems Limited | Information & communication | 1996 |
| Bottleneck Productions Ltd | Information & communication | 2025 |
| Boundary Fencing Contractors Limited | Construction | 1994 |
| Boundless Engineering Solutions Ltd | Professional & scientific | 2024 |
| Boundless View Ltd | Information & communication | 2017 |
| Boutique Brands Limited | Wholesale & retail | 2005 |
| Boutique Broadcast Ltd | Information & communication | 2022 |
| Bowden Construction Ltd | Construction | 2019 |
| Bowertone Enterprises Limited | | 1983 |
| Bowling Court Management Limited | Households | 1989 |
| Bowtie Brewers Limited | Manufacturing | 2018 |
| Box Clever Services Limited | Construction | 2020 |