| Blackspine Limited | Arts & recreation | 2004 |
| Blanc Noir Properties Ltd | Real estate | 2022 |
| Blanklines Ltd | Real estate | 2022 |
| Blue Box Storage Limited | Administrative & support | 2001 |
| Blue Concepts Ltd | Construction | 2005 |
| Blue Merlin Ltd | Professional & scientific | 2015 |
| Blue Rose Marketing Services Limited | Administrative & support | 2007 |
| Blue TIN Limited | Professional & scientific | 1998 |
| Blue White Sea Ltd | Arts & recreation | 2024 |
| Bluepoint Ltd | Information & communication | 2002 |
| Blueprince Limited | Professional & scientific | 2004 |
| Bluerock Care Homes Ltd | Hospitality | 2025 |
| Bluetidelamps Ltd | Wholesale & retail | 2025 |
| Bluewispornaments Ltd | Wholesale & retail | 2025 |
| Bluroc Consulting Limited | Other services | 2020 |
| Blythway Management Company Limited | Households | 1984 |
| Bolamide Consultants Limited | Information & communication | 1999 |
| Bonsai Media Limited | Administrative & support | 2004 |
| Booked for YOU Ltd | Other services | 2026 |
| Bourne Holidays Limited | Hospitality | 1984 |
| Bourne Holidays Transport Services Limited | Transport & logistics | 1992 |
| Bourne Leisure (Hopton) Limited | Hospitality | 1973 |
| Bourne Leisure Group Limited | Hospitality | 1969 |
| Bourne Leisure Holdings Limited | Hospitality | 2000 |
| Bourne Leisure Limited | Hospitality | 2000 |
| Bournemouth Montessori Centre Limited | Education | 2007 |
| Bowmans Lodge Limited | Real estate | 2004 |
| Box Hedgeco Limited | Financial services | 2021 |
| Box Midco Limited | Financial services | 2021 |
| Bozzo Bites Ltd | Hospitality | 2026 |
| BPM International (UK) Ltd. | Manufacturing | 2007 |
| Bradleys Painting & Decorating Limited | Construction | 1999 |
| Bradstock Power Tools Limited | Wholesale & retail | 1976 |
| Bramwood Limited | Households | 1990 |
| Brandsmaster Limited | Wholesale & retail | 2007 |
| BRD Projects Limited | Professional & scientific | 2021 |
| Bread & Fish 5000 Limited | Extraterritorial | 2007 |
| Breelance Technologies Ltd | Information & communication | 2020 |
| Brent Container Services (Skip Hire) Limited | Professional & scientific | 1974 |
| Brevins Limited | Professional & scientific | 2003 |
| Brian Head Consulting Limited | Professional & scientific | 2003 |
| Brian Milburn Limited | Information & communication | 2000 |
| Briarflair Limited | Construction | 1996 |
| Bridge Garage Services Limited | Wholesale & retail | 2002 |
| Bridge Street (Nominees) Limited | Professional & scientific | 1987 |
| Bridge-Logix UK Ltd | Information & communication | 2021 |
| Bridleways Limited | Wholesale & retail | 2002 |
| Brighton Property Developments Limited | Construction | 2004 |
| Brightpoint Consulting Limited | Information & communication | 2015 |
| Brindley Goldstein Limited | Professional & scientific | 2000 |
| British and Scandinavian Support Ukeig | | 2003 |
| British Pipeline Agency Limited | Transport & logistics | 1975 |
| Briton & Ensign Limited | Manufacturing | 1980 |
| Briton Plant Holdings Limited | Other services | 1972 |
| Broadfield & OTA Ltd | Professional & scientific | 1998 |
| Broadfields Garage Limited | Transport & logistics | 1989 |
| Broadoak Business Consultancy Limited | Professional & scientific | 1998 |
| Broadwell Enterprises Limited | Wholesale & retail | 2004 |
| Brogo Cardhouse Limited | Wholesale & retail | 2025 |
| Brompton Investment Group Limited | Real estate | 2019 |
| Brookjade Properties Limited | Construction | 1994 |
| Brookwell International Limited | Wholesale & retail | 2007 |
| Brunt, Finch, Radford & Company Limited | Professional & scientific | 2003 |
| Bses Limited | Construction | 2003 |
| Bspm Services Limited | Professional & scientific | 1992 |
| BTS Worldwide Ltd | Information & communication | 2017 |
| Bularyh Limited | Information & communication | 2000 |
| Bunting Magnetics Europe Limited | Manufacturing | 1964 |
| Burleigh Woods Residents Management Company Limited | Households | 2014 |
| Burns & Co. Limited | Wholesale & retail | 1979 |
| Bury & Bean Ltd | Wholesale & retail | 2002 |
| Bushby Family Holdings Ltd | Real estate | 2020 |
| Bushey Curry House Ltd | Hospitality | 2022 |
| Business UK Solutions Ltd | Administrative & support | 2021 |
| Butler & Stag Block and Estate Management Ltd | Real estate | 2024 |
| Button Holdings Limited | Financial services | 1992 |
| Button Trading Ltd | Wholesale & retail | 2025 |
| C & J Benham Limited | Financial services | 2026 |
| C & S (Fitout) Limited | Professional & scientific | 2012 |
| C and J Scott Financial Services Limited | Professional & scientific | 2007 |
| C G Plumbing & Heating Limited | Construction | 1997 |
| C P B Services Limited | Professional & scientific | 2003 |
| C R B Property Maintenance Limited | Construction | 1997 |
| C. C. Hydrosonics Limited | Manufacturing | 1973 |
| Caddie Shack Limited | Wholesale & retail | 2006 |
| Callis Investments Ltd | Real estate | 2018 |
| Cambridge Recruitment Software Solutions Ltd | Information & communication | 2007 |
| Cambridge Systems Associates Limited | Information & communication | 1996 |
| Camden Development Company Limited | Construction | 1963 |
| Camfield Estate Company Limited | Agriculture & fishing | 1964 |
| Camhurst Consulting Limited | Administrative & support | 2000 |
| CAN Solve Consultancy Limited | Construction | 2006 |
| Cancerpal Limited | Wholesale & retail | 2025 |
| Candour Care Services Limited | Health & social care | 2000 |
| Candy Decor Events Ltd | Hospitality | 2022 |
| Capital Benefits Limited | Wholesale & retail | 1992 |
| Capricorn Capital Limited | Information & communication | 2001 |
| Car Needs (Welwyn) Limited | Wholesale & retail | 2012 |
| Cara Hotel Marketing Limited | Wholesale & retail | 2004 |
| Cardel Limited | Manufacturing | 1996 |