| Burderop Park Residents Management Company Limited | Households | 2021 |
| Burfield Valley Estate Management Limited | Households | 2012 |
| Burger Home Ltd | Hospitality | 2025 |
| Burger London Ltd | Hospitality | 2021 |
| Burger Mafia Limited | Hospitality | 2021 |
| Burgers R US Ltd | Hospitality | 2023 |
| Burgess Close (Minster Thanet) Residents Association Limited | Households | 2003 |
| Burgess Croft Management Company Limited | Households | 2013 |
| Burgess House (Whyteleafe) Residents Company Limited | Real estate | 2005 |
| Burgundy & Black Limited | Hospitality | 2010 |
| Burhan Investing Limited | Financial services | 2021 |
| Burhanmedics Ltd | Health & social care | 2021 |
| Burke Estate Group Ltd | Real estate | 2026 |
| Burke Recruitment Solutions Ltd | Administrative & support | 2025 |
| Burlflower Investment Ltd | Real estate | 2019 |
| Burlington Court Management Company Limited | Households | 2002 |
| Burlington House (Richmond) Limited | Households | 2006 |
| Burlington Place (Hulme, Manchester) Management Company Limited | Households | 2000 |
| Burnage Court Limited | Households | 2004 |
| Burnage Court Management Co Limited | Households | 1995 |
| Burney Tomar Ltd | Professional & scientific | 2012 |
| Burnham Gardens Residents Association Limited | Households | 1987 |
| Burnikell Investments Limited | Construction | 2020 |
| Burnside Court (Romford) Management Limited | Households | 2001 |
| Burstow Court Management Limited | Households | 1996 |
| Burstow Grove (Horley) Maisonettes Management Company Limited | Households | 2026 |
| Burstow Grove (Horley) Management Company Limited | Households | 2025 |
| Burtai Refurbishment Ltd | Construction | 2024 |
| Burton Flour Mill Limited | Households | 2005 |
| Burton Place (Chelmsford) Management Company Limited | Households | 1985 |
| Burtons Farm Park Management Company Limited | Households | 2008 |
| Buru Conctruction Limited | Administrative & support | 2024 |
| Burwood Lodge Limited | Households | 2016 |
| Burybrooke Court Management Company Limited | Households | 1989 |
| Bush Holdings Ltd | Real estate | 2023 |
| Bush Properties Holdings Limited | Financial services | 2024 |
| Bushell Way Residents Association Limited | Households | 2013 |
| Bushey Local Limited | Wholesale & retail | 2010 |
| Business & Data Analytics Solutions Limited | Information & communication | 2016 |
| Business 247 Ltd | Administrative & support | 2022 |
| Business Allies Consulting Ltd | Professional & scientific | 2009 |
| Business Analysts Limited | | 1982 |
| Business Bods Limited | Professional & scientific | 2004 |
| Business Development Network Limited | Professional & scientific | 2010 |
| Business Process & Change Management Consultancy Ltd | Professional & scientific | 2022 |
| Business Production Ltd | Professional & scientific | 2020 |
| Business Support & Innovation Centre Ltd | Administrative & support | 2012 |
| Businessbuildadvisory Ltd | Administrative & support | 2018 |
| Businesschrome Limited | Information & communication | 2012 |
| Bussy Inc Limited | Extraterritorial | 2023 |
| Busy Minds Montessori Ltd | Health & social care | 2025 |
| Busyboys Productions Limited | Information & communication | 2023 |
| Butler & Young Lift Consultants Limited | Administrative & support | 1992 |
| Butler Court Management Limited | Households | 2019 |
| Butler Rentals Ltd | Households | 2014 |
| Butley Hall Management Company Limited | Households | 2012 |
| Butterchoclocs Ltd | Other services | 2020 |
| Buttercup RTM Company Limited | Households | 2008 |
| Butterley Deer Park Management Company Limited | Real estate | 2018 |
| Buttons Bear and Friends Limited | Extraterritorial | 1979 |
| Buy and TRY Ltd | Wholesale & retail | 2025 |
| Buy My Laptop Limited | Information & communication | 2017 |
| Buybrilliance Ltd | Wholesale & retail | 2025 |
| Buyerpoint Ltd | Wholesale & retail | 2022 |
| Buylery Ltd | Wholesale & retail | 2025 |
| BVR Productions Limited | Arts & recreation | 2024 |
| BW Broadcast Limited | Manufacturing | 2003 |
| BWG Botanics Ltd | Wholesale & retail | 2020 |
| BWP Photography Ltd | Professional & scientific | 2025 |
| BXB London Limited | Wholesale & retail | 2019 |
| BY -Blesbeauty Salon Limited | Other services | 2023 |
| BY Cocci Ltd | Hospitality | 2017 |
| BY Nelsz Ltd | Other services | 2025 |
| BY Properties Ltd | Real estate | 2022 |
| Byfield Good Books Limited | Wholesale & retail | 2006 |
| Bynd Performance Ltd | Health & social care | 2025 |
| Byranletech Ltd | Information & communication | 2025 |
| Byrne Resourcing Ltd | Administrative & support | 2024 |
| Byrom Fields (Wigan) Management Company Limited | Households | 2006 |
| Byron Management Company Limited | Households | 1988 |
| Byte Beadle Wholesale Ltd | Wholesale & retail | 2025 |
| Byte Promote Ltd | Professional & scientific | 2026 |
| Bytefy Technologies Limited | Extraterritorial | 2024 |
| Bywood Garage Ltd | Wholesale & retail | 2016 |
| Bywood Limited | Real estate | 1999 |
| BZ Cars Ltd | Transport & logistics | 2026 |
| BZ Housing Ltd | Real estate | 2024 |
| C & a Facilities Management Company Limited | Administrative & support | 2017 |
| C & J Electrical London Limited | Construction | 2020 |
| C & M Catering Equipment Limited | Hospitality | 2025 |
| C & P Panelcraft Limited | Wholesale & retail | 1994 |
| C & V Construction Ltd | Construction | 2019 |
| C & V Gill Ltd | Other services | 2010 |
| C a James Ltd | Other services | 2016 |
| C Asam Health Ltd | Health & social care | 2023 |
| C C M Supplies Limited | Wholesale & retail | 1988 |
| C H William Property Services Limited | Construction | 2024 |
| C I Sufaru Ltd | Construction | 2023 |
| C J Clean UK Limited | Administrative & support | 2020 |
| C J Louis Limited | Wholesale & retail | 2019 |