| Brickfield Construction Limited | Construction | 2009 |
| Brickfield Group Ltd | Financial services | 2026 |
| Brickfield Homes Limited | Construction | 2015 |
| Bridge & Connect Ltd | Other services | 2013 |
| Bridge Property London Ltd | Real estate | 2014 |
| Bridge Road Consultants Limited | Professional & scientific | 2012 |
| Bridge Shoreditch Limited | Administrative & support | 2009 |
| Bridgeways Advisory Limited | Professional & scientific | 2025 |
| Bridor UK Limited | Wholesale & retail | 2019 |
| Bright Care 4U Ltd | Health & social care | 2024 |
| Bristol Aviation Company Limited(The) | Extraterritorial | 1910 |
| Brit AI Limited | Information & communication | 2025 |
| Brit Cars Ltd | Transport & logistics | 2024 |
| Brit Legacy Ltd | Wholesale & retail | 2026 |
| British Aircraft Corporation (Pension Fund Trustees) Limited | Extraterritorial | 1963 |
| British Aircraft Corporation Limited | Extraterritorial | 1963 |
| BRN Holdings Ltd | Water & waste | 2017 |
| BRN Property Ltd | Real estate | 2020 |
| Broadbados Ltd | Real estate | 2023 |
| Broadsword Consulting Ltd | Professional & scientific | 2024 |
| Broadwater Acquisitions 2 Limited | Financial services | 2017 |
| Bromcount Limited | Wholesale & retail | 1976 |
| Brompton House Management Company Limited(The) | Households | 1975 |
| Brondesbury Ltd | Real estate | 2009 |
| Bronslace 25 Limited | Other services | 2020 |
| Bronzed Fleet Ltd | Other services | 2024 |
| Brooks & Allen Limited | Real estate | 2018 |
| Brooks Saddles Limited | Professional & scientific | 2000 |
| Broomco Limited | Manufacturing | 1990 |
| Broomhurst Group Limited | Real estate | 2017 |
| Broomhurst Limited | Real estate | 1989 |
| Bros Food & Drinks Ltd | Hospitality | 2024 |
| Brothercarp Ltd | Information & communication | 2026 |
| Brynmaer House Management Limited | Households | 2014 |
| BS Precision Engineering Ltd | Professional & scientific | 2023 |
| BS24 Limited | Health & social care | 2009 |
| BSA Contractors Ltd | Construction | 2015 |
| Bsafe Care Ltd | Health & social care | 2024 |
| Bsmith Consulting Ltd | Professional & scientific | 2024 |
| BT Convergence Technologies Limited | Information & communication | 2025 |
| BTR Property Management Ltd | Real estate | 2022 |
| Bubble Tang T/A (Mcchina WOK Away Camberley) Ltd | Hospitality | 2022 |
| Buco Plumbing & Heating Limited | Construction | 2023 |
| Bugle Events Ltd | Hospitality | 2022 |
| Builders JS Ltd | Construction | 2012 |
| Building the Way Ltd | Construction | 2013 |
| Buildmasters South Ltd | Construction | 2025 |
| Buildsi Limited | Information & communication | 2012 |
| Buildwizer Construction Ltd | Construction | 2019 |
| Bulgaru Motors Ltd | Wholesale & retail | 2024 |
| Bullen & Co Accountants Limited | Professional & scientific | 2012 |
| Bulmer Estates Limited | Extraterritorial | 2007 |
| Buncado Holdings Ltd | Real estate | 2025 |
| Buncado Ltd | Wholesale & retail | 2023 |
| Bunny HOP Ltd | Health & social care | 2013 |
| Bunny's Pet Behaviour Services Limited | Professional & scientific | 2016 |
| Bunti Glow and Style Ltd | Other services | 2026 |
| Burastudio Ltd | Professional & scientific | 2026 |
| Burghfield Dental Care Limited | Health & social care | 2008 |
| Burgundy Grand CRU Ltd | Wholesale & retail | 2025 |
| Burley Landscapes Limited | Administrative & support | 2013 |
| Burnham Manor Residents Association Limited | Households | 1966 |
| Burnt Toast Property Ltd | Real estate | 2025 |
| Burov Ltd | Health & social care | 2019 |
| Burrows Developments Limited | Construction | 2026 |
| Busboe Flight Training Ltd | Transport & logistics | 2025 |
| Bush Property Management Limited | Extraterritorial | 1994 |
| Business Driven IT Limited | Information & communication | 2010 |
| Business, Information Technology and Training Services Limited | Information & communication | 2006 |
| Butleigh Financial Services Limited | Professional & scientific | 2025 |
| Butler & Goddard Building Services Ltd | Construction | 2016 |
| Butlers of Binfield Limited | Wholesale & retail | 2021 |
| Butt Miller Limited | Professional & scientific | 2012 |
| Butterfields Property Ltd | Real estate | 2026 |
| Buttermere Homes Surrey Limited | Real estate | 2016 |
| Buttoned UP Studios Ltd | Information & communication | 2017 |
| BUZ Events Ltd | Hospitality | 2024 |
| Buzatu Logistics Ltd | Transport & logistics | 2026 |
| BW Procurement Limited | Professional & scientific | 2024 |
| BWA Invesco Ltd | Education | 2025 |
| BWK Group Limited | Administrative & support | 2025 |
| BY the Green Residents Company Limited | Households | 2017 |
| Byte Sensei Ltd | Information & communication | 2021 |
| Bytza 88 Ltd | Construction | 2017 |
| BZ Archtech-Surveyors Ltd | Construction | 2023 |
| C & M Roofing and Building Ltd | Construction | 2019 |
| C a Watson General Builder / Contractor Ltd | Construction | 2014 |
| C and S Property Management Limited | Construction | 2022 |
| C E J Grig Limited | Manufacturing | 2013 |
| C F Lettings (Bath) Limited | Extraterritorial | 2009 |
| C FOY Holdings Ltd | Professional & scientific | 2021 |
| C H Electrical Limited | Construction | 1997 |
| C J Carter Ltd | Manufacturing | 2015 |
| C J Williams Consulting Ltd | Professional & scientific | 2020 |
| C M Beach Contracting Ltd | Agriculture & fishing | 2023 |
| C&E Recruitment Limited | Administrative & support | 2014 |
| C&K.Solutions Ltd | Wholesale & retail | 2025 |
| C&S Films Ltd | Information & communication | 2018 |
| C.Pepper & SON Limited | Construction | 1963 |
| C2 Foods Ltd | Hospitality | 2024 |