| BO Peep Caravan Park Limited | Hospitality | 2002 |
| BO Peep Events Limited | Administrative & support | 2012 |
| BO Scaffolding Services (Boss) Ltd | Construction | 2020 |
| Body Beautiful HB Limited | Administrative & support | 2021 |
| Bogdan Nastase Ltd | Transport & logistics | 2026 |
| Bolg Ltd | Construction | 2019 |
| Bonbon & Belle Ltd | Wholesale & retail | 2025 |
| Bonnes Mares Limited | Real estate | 2006 |
| Boom Driving School Ltd | Education | 2023 |
| Boomerang Pro Fitness Ltd | Arts & recreation | 2015 |
| Bordon Hill Nurseries Limited | Agriculture & fishing | 2000 |
| Borg & Beck Ltd | Wholesale & retail | 2019 |
| Boris Construct Ltd | Construction | 2019 |
| Bosloe's Creative Chaos Ltd | Arts & recreation | 2024 |
| Bostanel Ltd | Transport & logistics | 2026 |
| Bostanica Ltd | Transport & logistics | 2024 |
| Botanicum Limited | Wholesale & retail | 2023 |
| BOTT&TAYLOR26 Ltd | Wholesale & retail | 2026 |
| Bouncing Limited | Information & communication | 2000 |
| Bourton Drain Services Ltd | Administrative & support | 2005 |
| Bowbridge Homes (Hose) Ltd | Construction | 2023 |
| BOX15 Ltd | Wholesale & retail | 2014 |
| Boyles Autos Limited | Wholesale & retail | 2022 |
| Bpbordeianu Limited | Transport & logistics | 2023 |
| Brackley Antique Cellar Limited | Wholesale & retail | 1990 |
| Brackley Courier & Light Haulage Service Ltd | Transport & logistics | 2026 |
| Brackley Glass Ltd | Construction | 2025 |
| Brackley Industrial Maintenance Limited | Construction | 2001 |
| Brackley Mews Management Limited | Real estate | 2001 |
| Bradbeer Agencies Ltd | Administrative & support | 2011 |
| Bradbury's of Banbury Ltd | Wholesale & retail | 2025 |
| Bradshaw Agricultural Holdings Limited | Professional & scientific | 1974 |
| Bradshaw B2L Limited | Real estate | 2026 |
| Bradshaw Finco Limited | Professional & scientific | 2024 |
| Bradshaw Property Holdings Limited | Financial services | 2019 |
| Brady European Holdings Limited | Financial services | 2005 |
| Braich and Bassi Properties Limited | Construction | 2022 |
| Brailes Housing Association Limited | Other services | 2011 |
| Brainy Botz Limited | Education | 2025 |
| Bralewski Signature Events Ltd | Administrative & support | 2025 |
| Bramford Limited | Hospitality | 2003 |
| Bramford Realty Limited | Real estate | 2016 |
| Brand IQ Marketing Ltd | Professional & scientific | 2019 |
| Brand New Roofing Limited | Construction | 2003 |
| Brand Refill Limited | Extraterritorial | 2011 |
| Brandand Limited | Manufacturing | 2006 |
| Brashesbrushes Ltd | Wholesale & retail | 2025 |
| Bravo Realty Limited | Real estate | 2018 |
| Braydon Lane Limited | Real estate | 2020 |
| BRD Environmental Limited | Professional & scientific | 2000 |
| Breadline Project | Other services | 2021 |
| Brecon Garden Company Limited | Administrative & support | 2024 |
| Breeding Vision Limited | Agriculture & fishing | 2004 |
| Breezesim Limited | Information & communication | 2025 |
| Breezeway Consulting Limited | Professional & scientific | 2024 |
| Breezi Cooling UK Ltd | Energy | 2025 |
| Brelade Group Ltd | Administrative & support | 2024 |
| Brenton Properties Limited | Real estate | 2006 |
| Brett’S Bespoke Kitchen Limited | Hospitality | 2024 |
| Brew Box Ltd | Hospitality | 2020 |
| Brick Kiln Composites Limited | Manufacturing | 2013 |
| Bridepeak Limited | Extraterritorial | 2001 |
| Bridge Lake Leisure LLP | | 2019 |
| Bridgeway Healthcare Services Ltd | Administrative & support | 2026 |
| Briefable Ltd | Information & communication | 2026 |
| Bright Accountancy Services Limited | Professional & scientific | 2023 |
| Brighten Care and Training Services Ltd | Education | 2021 |
| Brighton Works Limited | Real estate | 2018 |
| Brightstone Property Management Limited | Construction | 2021 |
| Brilliant Brows & Lash Bar Ltd | Other services | 2015 |
| Bristol Fire Limited | Manufacturing | 2011 |
| Bristol York Holdings Ltd | Financial services | 2023 |
| Britannia Bridge Capital Ltd | Real estate | 2024 |
| Britannia Joinery Limited | Manufacturing | 2012 |
| Britannia Wharf Management Limited | Real estate | 1986 |
| British Furniture Association Ltd | Other services | 1949 |
| British Microlight Aircraft Association Limited | Other services | 1982 |
| British Valve and Actuator Association Limited | Other services | 1973 |
| Britmet Group Holdings Limited | Financial services | 2023 |
| Britmet Holdings Limited | Financial services | 2012 |
| Britmet Tileform Limited | Construction | 1995 |
| Britteco Ltd | Water & waste | 2017 |
| BRO Force Ltd | Transport & logistics | 2024 |
| Broad & Devitt Fine Wines Ltd. | Wholesale & retail | 2011 |
| Broadband Go Limited | Information & communication | 2020 |
| Broadgate Lettings Limited | Real estate | 2018 |
| Broadmoor Estates Ltd | Agriculture & fishing | 2025 |
| Brodey Capital Ltd | Real estate | 2021 |
| Bromley Services Ltd | Construction | 2017 |
| Bronze Byte Limited | Manufacturing | 2025 |
| Brookfield Farm Chipping Warden Ltd | Agriculture & fishing | 2011 |
| Brooks & Davies Group Ltd | Extraterritorial | 2016 |
| Brooks Financial Services Ltd | Financial services | 2018 |
| Brooks Plumbing and Heating Solutions Ltd | Construction | 2025 |
| Brookside Legacy Limited | Real estate | 2022 |
| Broughan & SON Consulting Limited | Information & communication | 2000 |
| BRS Automotive Ltd | Wholesale & retail | 2017 |
| Bruce Hopkins Limited | Wholesale & retail | 1976 |
| Brunswick Motors (Banbury) Limited | Wholesale & retail | 2011 |
| Bruton Ventures Limited | Hospitality | 2025 |