| Bourne Group Consulting Ltd. | Professional & scientific | 2017 |
| Bourne Twyford Limited | Administrative & support | 2011 |
| Bourne Valley Eggs Limited | Agriculture & fishing | 2025 |
| Bournebeech Limited | Real estate | 2024 |
| BOV Boys Entertainment Ltd | Information & communication | 2025 |
| BOW Mgmt Ltd | Professional & scientific | 2023 |
| BOW Property Ltd | Real estate | 2016 |
| Bowen Energy Limited | Administrative & support | 2024 |
| Bowland Health Hub Ltd | Real estate | 2025 |
| Bowland House Management Ltd | Real estate | 2023 |
| Box Group Holdings Limited | Financial services | 2015 |
| Box Space Limited | Real estate | 2012 |
| Box-It Data Management Limited | Professional & scientific | 2010 |
| Box-It Document Solutions Limited | Administrative & support | 1989 |
| Box-It Outsourcing Limited | Other services | 2005 |
| Box-It U.K. Ltd | Transport & logistics | 1995 |
| Boyz Ltd | Wholesale & retail | 2004 |
| Bpmpro Ltd | Professional & scientific | 2012 |
| Brabham Global Limited | Arts & recreation | 2014 |
| Brabham Group Limited | Administrative & support | 2013 |
| Brabham Motorsport Limited | Other services | 2013 |
| Brackenlea Care Homes Limited | Health & social care | 2015 |
| Brackenwood Polo Limited | Administrative & support | 2005 |
| Bradbury Management Ltd | Information & communication | 2023 |
| Brain Products UK Ltd | Health & social care | 2016 |
| Brain Tumour Surgery Limited | Health & social care | 2010 |
| Brain Vision (UK) Ltd | Health & social care | 2021 |
| Brain Vision (US) Ltd | Wholesale & retail | 2004 |
| Bramdean Garage Enterprises Limited | Wholesale & retail | 2025 |
| Bramdean Garage Limited | Wholesale & retail | 1970 |
| Bramdean Sleepers Ltd | Agriculture & fishing | 2023 |
| Brand Ambitions Limited | Real estate | 2009 |
| Brandt Urban Design Ltd | Professional & scientific | 2025 |
| Brangus Limited | Other services | 2015 |
| Brave Organisation Limited | Financial services | 2022 |
| Bravo Solutions Limited | Information & communication | 1997 |
| Bray Technologies Ltd | Information & communication | 2025 |
| Braymont Construction Limited | Construction | 2022 |
| Braymont Ltd | Real estate | 2006 |
| Breakthroo Limited | Information & communication | 2002 |
| Brenner Developments Limited | Construction | 2025 |
| Bressummer A.R.K. Limited | Real estate | 2023 |
| Brett Group Ltd | Real estate | 2026 |
| Brewhouse Equity Partners Ltd | Financial services | 2025 |
| Brian Holtzhausen Ltd | Wholesale & retail | 2020 |
| Briarlea Properties | Real estate | 2016 |
| Bridgetts Lane Residents Association Limited | Households | 2005 |
| Bridgwater Tyre & Exhaust Limited | Extraterritorial | 2007 |
| Bright CG Ltd | Professional & scientific | 2023 |
| Bright Consulting Group Limited | Professional & scientific | 2016 |
| Bright Eyes Clothing Limited | Wholesale & retail | 2018 |
| Bright Trace Electronics Ltd | Manufacturing | 2025 |
| Bright Verse Consulting Limited | Professional & scientific | 2023 |
| Brijan Tours Limited | Transport & logistics | 2001 |
| Brilliant Window Films and Graphics Ltd | Construction | 2024 |
| Bristol Paediatric Clinic Limited | Health & social care | 2023 |
| British Classics Reborn Limited | Wholesale & retail | 2025 |
| British Liver Trust | Health & social care | 1988 |
| Britiva Innovations Ltd | Wholesale & retail | 2024 |
| Broad Chalke Training Services Limited | Other services | 2025 |
| Broadchalk Door Services Limited | Construction | 2007 |
| Broadreed (2000) Limited | Real estate | 2000 |
| Broadreed Limited | Agriculture & fishing | 1963 |
| Broadview Winchester Ltd | Other services | 2019 |
| Brockwood Consulting Limited | Administrative & support | 2019 |
| Brojo Ltd | Extraterritorial | 2016 |
| Brookfield Property Management Limited | Real estate | 2013 |
| Brookhill (Kingswear) Management Company Limited(The) | Households | 1964 |
| Brooking Director Services Limited | Professional & scientific | 1996 |
| Brooks & Sons Engineering Ltd | Professional & scientific | 2024 |
| Brookside Vehicle Remarketing Limited | Professional & scientific | 2013 |
| Brookvale Healthcare Limited | Health & social care | 2000 |
| Broom Close Car Park Ltd | Transport & logistics | 2014 |
| Broxmouth Solutions Ltd | Professional & scientific | 2018 |
| Bruce Greig Ltd | Professional & scientific | 2018 |
| Brunton Business Publications Limited | Information & communication | 1987 |
| Bruton One Bess Limited | Information & communication | 2022 |
| Bruton One Limited | Real estate | 2022 |
| Bryanston Holt Management Company Limited | Households | 2024 |
| Brymor Group Holdings Limited | Financial services | 2022 |
| Bsixtwelve Limited | Agriculture & fishing | 2017 |
| Bsjk Investments Limited | Financial services | 2025 |
| BSW Cardiology LLP | | 2024 |
| Buchanan's Place Management Company Limited | Households | 2017 |
| Buckdean Ltd | Professional & scientific | 2021 |
| Buckingham Court Freehold Limited | Households | 2016 |
| Buckland Capital Partners Limited | Financial services | 2007 |
| Buckland Construction Limited | Extraterritorial | 2024 |
| Buckland Development Limited | Administrative & support | 2006 |
| Buckland Group Limited | Professional & scientific | 2010 |
| Buckland Holdings Limited | Professional & scientific | 2019 |
| Buckley Two Wheel Centre Limited | Extraterritorial | 2017 |
| Buddlesgate Ltd | Professional & scientific | 2018 |
| Budget Motorist Centres Limited | Extraterritorial | 1985 |
| Budz Afterschool Club Ltd | Health & social care | 2019 |
| Buggaboo Ltd | Financial services | 2021 |
| Bugs Grass Care and Maintenance Limited | Administrative & support | 2020 |
| Build & Develop Limited | Construction | 2007 |
| Build Planet Ltd | Construction | 2023 |
| Building Bespoke Limited | Construction | 2000 |