| Bridges Woodwork Ltd | Manufacturing | 2022 |
| Bridgeside Mews Flats Management Company Limited | Households | 2002 |
| Bridgeside Mews Housing Management Company Limited | Real estate | 2002 |
| Bridgewood Place RTM Company Limited | Households | 2009 |
| Bridon Properties Ltd | Real estate | 2022 |
| Bright Associates Limited | Wholesale & retail | 2003 |
| Bright Horizon Services Limited | Information & communication | 2024 |
| Bright Tribe Trust | Education | 2012 |
| Brightarc Welding Limited | Manufacturing | 2006 |
| Brightheads Nursery Limited | Health & social care | 2025 |
| Brighton Bariatrics Limited | Health & social care | 2023 |
| Brightpath Education Services Limited | Education | 2025 |
| Brightwood Camps Ltd | Arts & recreation | 2026 |
| Brilliant Creative Limited | Professional & scientific | 2014 |
| Brindle Jones Ltd | Construction | 2025 |
| Brisan Accountancy Ltd | Professional & scientific | 2014 |
| Brisan Group Ltd | Professional & scientific | 2023 |
| Brishing Barn Nursery Limited | Education | 2010 |
| Britannic Catering Limited | Hospitality | 2025 |
| British American Optical Company Limited | Extraterritorial | 2007 |
| British Fire Advisory Services Limited | Public administration | 2000 |
| British HOP Products Limited | Extraterritorial | 1974 |
| British Institute and Association of Electrolysis Limited | Other services | 1956 |
| Broadcrafting Limited | Information & communication | 2016 |
| Broadmead Storage Limited | Hospitality | 1973 |
| Broadnet Communications Systems Limited | Information & communication | 2015 |
| Broadoak Safety Consulting Ltd | Professional & scientific | 2023 |
| Broadway Auto Centres Limited | Wholesale & retail | 2008 |
| Broadway Heights 1962 Limited | Extraterritorial | 2015 |
| Brock Media Limited | Arts & recreation | 2012 |
| Brockenhurst International Ltd | Wholesale & retail | 2019 |
| Broedan Property Management Ltd | Real estate | 2025 |
| Brogan's Jewellers Ltd | Wholesale & retail | 2007 |
| Brogdale CIC | Health & social care | 2010 |
| Brogdale Market Ltd | Agriculture & fishing | 1990 |
| Bronzin Beauty Salon Limited | Other services | 2018 |
| Brood Restaurant Limited | Other services | 2000 |
| Brook Archaeology Limited | Professional & scientific | 2022 |
| Brook Frank Limited | Professional & scientific | 2020 |
| Brookbanks Limited | Real estate | 2004 |
| Brookbelle Limited | Agriculture & fishing | 2021 |
| Brooke Close and Roman Way Management Limited | Households | 2020 |
| Brookes Hair Clinic Ltd | Other services | 2024 |
| Brookfield Mansions (Freehold) Limited | Households | 2004 |
| Brookline Coaches Limited | Transport & logistics | 2005 |
| Brooks Bar Services Limited | Hospitality | 2019 |
| Brooks Building Consultants Ltd | Construction | 2014 |
| Brooks Harper & Co Limited | Real estate | 2025 |
| Brooks Marquee Hire Limited | Arts & recreation | 2019 |
| Brother Parcel Post Ltd | Transport & logistics | 2015 |
| Brotherbrother Films Limited | Information & communication | 2011 |
| Brothers Jordan Ltd | Construction | 2022 |
| Broughtie Capital Limited | Real estate | 2020 |
| Brown and Mills Entertainment Limited | Arts & recreation | 2013 |
| Brown Bear Security Solutions Ltd | Administrative & support | 2025 |
| Brown New Homes Limited | Construction | 2023 |
| Brown Town Properties Limited | Other services | 2020 |
| Browning Rose Financial Limited | Financial services | 2015 |
| Browning Rose Wealth Management Ltd | Financial services | 2025 |
| BRS Traffic Management Limited | Construction | 2020 |
| Bruce Accounts Limited | Professional & scientific | 2002 |
| Bruce Bourne Associates LLP | | 2011 |
| Brunels Bakery Limited | Wholesale & retail | 2018 |
| Bruno Hasse Ltd | Transport & logistics | 2020 |
| Brunswick Mews Residents Company Limited | Households | 2008 |
| Brush Books Ltd | Wholesale & retail | 2023 |
| Bryan Fixings Ltd | Construction | 2006 |
| Bryanston Court II Residents Association Limited | Households | 1981 |
| Bryant Barbers Group Ltd | Other services | 2019 |
| Bryant CCS Ltd | Information & communication | 2023 |
| Bryant NLP Ltd | Health & social care | 2025 |
| Bryson Rubbish Clearance Limited | Water & waste | 2017 |
| Brytish Consulting Ltd | Transport & logistics | 2017 |
| BSC Property Ltd | Households | 2020 |
| Bshg Limited | Wholesale & retail | 2011 |
| Bsmith Ltd | Wholesale & retail | 2023 |
| BSO Solutions Ltd | Professional & scientific | 2022 |
| BSS Leadworks Ltd | Construction | 2025 |
| BT Environmental Ltd | Other services | 2017 |
| Btitcombe Ltd | Construction | 2022 |
| Btrme Limited | Professional & scientific | 2015 |
| Buckland Architectural Developments Ltd | Construction | 2023 |
| Buckwillow Limited | Real estate | 2022 |
| Budget Blanks Ltd | Wholesale & retail | 2025 |
| Budget Click Media Ltd | Professional & scientific | 2026 |
| Buenos Aires Nights Limited | Hospitality | 2017 |
| Buful Ltd | Wholesale & retail | 2020 |
| Buggy Beats Limited | Information & communication | 2015 |
| Build My Web Ltd | Information & communication | 2017 |
| Builder Builder Ltd | Construction | 2025 |
| Buildermaster Ltd | Construction | 2014 |
| Building Fit & Renovations Limited | Manufacturing | 2024 |
| Buildmark Solutions Ltd | Construction | 2025 |
| Buildspace Group Limited | Administrative & support | 2013 |
| Built Environment Signage Solutions Ltd | Manufacturing | 2026 |
| Bukkitinggi Limited | Professional & scientific | 2006 |
| Bulg Install Ltd. | Construction | 2011 |
| Bull Property Investments Limited | Real estate | 2019 |
| Bull Sprint Ltd | Transport & logistics | 2021 |
| Bumble BEE Developments Limited | Real estate | 2019 |