| Bluestar Offshore Electrical Ltd | Professional & scientific | 2026 |
| Blush Design & Marketing Services Ltd | Manufacturing | 2019 |
| BN Sports Ltd | Arts & recreation | 2025 |
| BNP Paribas Commercial Finance Limited | Financial services | 1992 |
| Bnsc Ltd | Information & communication | 2024 |
| Boardnet Ltd. | Administrative & support | 2016 |
| Boardroom Insights LLP | | 2006 |
| Boardwell Ltd. | Hospitality | 2010 |
| Boats for Sale Limited | Wholesale & retail | 2010 |
| Bodiam Builders Limited | Construction | 2010 |
| Bodiam Leisure Limited | Administrative & support | 2017 |
| Bodiam Winery Ltd | Administrative & support | 2017 |
| Bogen Limited | Professional & scientific | 2009 |
| Boiler Today Ltd | Construction | 2019 |
| Bol-C Ltd | Agriculture & fishing | 2020 |
| Bold Bean Coaching Ltd | Professional & scientific | 2017 |
| Bold Horizon International Limited | Professional & scientific | 2025 |
| Boldtime Limited | Professional & scientific | 1997 |
| Bolney Green Energy Hub 4 Limited | Energy | 2022 |
| Bolney Green Energy Hub Limited | Extraterritorial | 2024 |
| Bolnore Village Community Interest Company | Households | 2016 |
| Bolnore Village Management Company Limited | Households | 2012 |
| Bolsa Media Limited | Information & communication | 2015 |
| Bolton Investment Assets Limited | Real estate | 2024 |
| Bolton Property Management LLP | | 2024 |
| Boman (Maidstone) Limited | Real estate | 2022 |
| Boman Scripps Ltd | Real estate | 2016 |
| BON Appéteat Ltd | Professional & scientific | 2019 |
| Bonaly House Management Company Limited | Households | 2001 |
| Bonane Limited | Professional & scientific | 2021 |
| Bonaventures Investments Limited | Real estate | 2025 |
| Boojum Consultancy Limited | Professional & scientific | 2013 |
| Book-Keeping Bliss Ltd | Professional & scientific | 2017 |
| Bookomi Ltd | Administrative & support | 2012 |
| Boom Badminton Community Sports Club Ltd | Arts & recreation | 2024 |
| Bora Studio Limited | Arts & recreation | 2016 |
| Boropat Industries Limited | Professional & scientific | 2017 |
| Boste Fitness Ltd | Arts & recreation | 2021 |
| Botanic Works Ltd | Administrative & support | 2025 |
| Botanica Health Ltd | Other services | 2008 |
| Bottom UP Blinds Limited | Administrative & support | 2000 |
| Botuto Limited | Information & communication | 2023 |
| Bounce Childrens Therapy Limited | Health & social care | 2011 |
| Boundary Represents Ltd | Administrative & support | 2025 |
| Bourne Brands Ltd | Wholesale & retail | 2025 |
| Bournelea Ltd | Financial services | 2022 |
| Bousba Property Limited | Real estate | 2015 |
| Bower Holdings Ltd | Agriculture & fishing | 2018 |
| Bowles Rocks Trust Limited | Education | 1964 |
| Bowsider Limited | Manufacturing | 2024 |
| Box and Docs Limited | Construction | 2014 |
| Box Delta Holdings Ltd | Financial services | 2023 |
| Box Delta Ltd | Financial services | 2020 |
| Boxall Studio Ltd | Professional & scientific | 2019 |
| Boyne House Management Company Limited | Real estate | 1997 |
| Boyne Park Management Company Limited | Households | 2005 |
| BPS Financial Ltd | Professional & scientific | 2019 |
| Bracketts LLP | | 2011 |
| Braeburn Fields Management Company Limited | Real estate | 2024 |
| Braemar Structural Design Ltd | Professional & scientific | 2019 |
| Braewich Ltd | Real estate | 2020 |
| Braign Studio Ltd | Professional & scientific | 2025 |
| Brains Matter Charity | Health & social care | 1997 |
| Braintreeit Limited | Information & communication | 2015 |
| Bramall House Properties Limited | Real estate | 2003 |
| Brambilla Limited | Construction | 2005 |
| Bramble NT Limited | Real estate | 2022 |
| Bramble Stone Developments Ltd | Professional & scientific | 2025 |
| Bramhall Lodge Limited | Households | 2016 |
| Brampton Eastbourne Limited | Construction | 2020 |
| Brand Corporation Limited | Other services | 2025 |
| Brandclad Limited | Construction | 1987 |
| Branding FE Limited | Professional & scientific | 2013 |
| Brandsmith Global Limited | Professional & scientific | 2014 |
| Brango Solutions Ltd | Professional & scientific | 2026 |
| Brave IT Limited | Information & communication | 2021 |
| Bravo Access Online Ltd | Wholesale & retail | 2025 |
| Bravo Acer Ltd | Wholesale & retail | 2025 |
| Bravo's Catering Van Ltd | Hospitality | 2023 |
| Bray-B-Que Ltd | Hospitality | 2024 |
| Braybourne Limited | Households | 1980 |
| Break Aways Ltd | Wholesale & retail | 2024 |
| Breast & Endocrine Health LLP | | 2011 |
| Breast & Endocrine Health UK Ltd | Health & social care | 2010 |
| Breath of Fresh Air Ltd | Education | 2014 |
| Bredbury House 2 RTM Company Limited | Households | 2020 |
| Bredbury House Management Ltd | Households | 2008 |
| Breevon Ltd | Wholesale & retail | 2025 |
| Breeze Networks Limited | Professional & scientific | 2016 |
| Brendan Corcoran Ltd | Information & communication | 2024 |
| Brentor Court Management Company Limited | Households | 1973 |
| Brentwood Freehold Management (2011) Limited | Households | 2011 |
| Bretaneby Management Company (Sevenoaks) Limited | Households | 1976 |
| Bretton Limited | Construction | 1985 |
| Brew PUB Limited | Hospitality | 2013 |
| Brian Lawrence Ltd. | Professional & scientific | 1995 |
| Briant Champion Long Services Limited | Real estate | 1986 |
| Bridge House (Tunbridge Wells) Limited | Households | 1986 |
| Bridge Point DIP Special Situations Lending Limited | Real estate | 2023 |
| Bridgeoak Private Finance Limited | Extraterritorial | 2019 |