| Beauty on the Square Ltd | Other services | 2024 |
| Beautyful Hair & Beauty Limited | Other services | 2019 |
| Beautyful Hair Ltd | Other services | 2019 |
| Bedingfield and Gater Limited | Real estate | 1959 |
| Bedson Agri Services Ltd | Manufacturing | 2025 |
| Beechys Autos Ltd | Wholesale & retail | 2024 |
| Beecliffe Property Ltd | Real estate | 2025 |
| Beeps Sweets and Treat Limited | Wholesale & retail | 2025 |
| Behind the Camera Studios Ltd | Arts & recreation | 2026 |
| Beijing Dingyang Science and Technology Development (UK) Ltd | Professional & scientific | 2019 |
| Beleth Contracting UK Limited | Construction | 2016 |
| Belfast Road Ballynahinch Management Company Limited | Real estate | 2022 |
| Belfore Global Ltd | Professional & scientific | 2017 |
| Belgrave Property Services Limited | Real estate | 1995 |
| Bell Agri Contracts Ltd | Agriculture & fishing | 2014 |
| Bell's Property Services (Staffordshire) Ltd. | Real estate | 2016 |
| Bella Capelli Hair & Beauty Limited | Other services | 2013 |
| Belle View Apartments Management Company Limited | Real estate | 2023 |
| Belsay Shooting Ground Limited | Arts & recreation | 2020 |
| Belta PR Limited | Professional & scientific | 2026 |
| Bemorevic Ltd | Health & social care | 2025 |
| Bennett Architectural Aluminium Solutions Ltd | Construction | 1960 |
| Benore Care Limited | Health & social care | 2005 |
| Bentleys Caterers & Consultancy Ltd | Hospitality | 2023 |
| Bernadetto Properties Ltd | Real estate | 2023 |
| Bernardo Verdin Ltd | Health & social care | 2022 |
| Bernomurpo Ltd | Real estate | 2025 |
| Berry Sonography Ltd | Health & social care | 2026 |
| Best Kept Cleaning Services Limited | Households | 2016 |
| Best Tyre Company Limited | Wholesale & retail | 2003 |
| Bestwood Pumping Station Limited | Other services | 2026 |
| Betd Components Limited | Wholesale & retail | 2016 |
| Beteo Ltd | Extraterritorial | 2023 |
| Betley Oak Ltd | Construction | 2011 |
| Bibizgeng Limited | Households | 2024 |
| Billykara Ltd | Wholesale & retail | 2019 |
| BIM Design Studio Limited | Professional & scientific | 2019 |
| BIO Media Ltd | Manufacturing | 2019 |
| Biocomposites (UK) Limited | Professional & scientific | 1999 |
| Biocomposites International Limited | Financial services | 2022 |
| Biocomposites Limited | Manufacturing | 1996 |
| Biomass Combustion Limited | Water & waste | 2006 |
| Biomass Power Limited | Professional & scientific | 2026 |
| Birch Electrical Limited | Construction | 2000 |
| Bird House Peckham Ltd | Hospitality | 2022 |
| Bird Vending Limited | Wholesale & retail | 2024 |
| BIS Partners LLC | | 2018 |
| Bitlogic Ltd | Manufacturing | 2019 |
| Bizwomen Hub Community Interest Company | Professional & scientific | 2025 |
| Bizzy BEE (NI) Limited | Hospitality | 2011 |
| BJ Property Project Ltd | Real estate | 2024 |
| Bjoris Properties Limited | Real estate | 2023 |
| BJW Health and Safety Services Limited | Professional & scientific | 2022 |
| BKM Steel Construction Limited | Construction | 2002 |
| Bkps Limited | Professional & scientific | 2009 |
| Black Box Bakery Ltd | Manufacturing | 2026 |
| Black Opal Tattoo Limited | Other services | 2020 |
| Black Stairs Ltd | Real estate | 2021 |
| Blackband Ltd | Real estate | 2023 |
| Blackcliff Ltd | Real estate | 2023 |
| Blackfriars Medieval Garden Community Interest Company | Extraterritorial | 2009 |
| Blacklake Lodge Ltd | Administrative & support | 1998 |
| Blackshaw Limited | Real estate | 2025 |
| Blackwhitedenim Ltd | Wholesale & retail | 2010 |
| Blades Newc Ltd | Manufacturing | 2025 |
| Blaney Holdings Limited | Construction | 2018 |
| Blenkinsopp Collieries Limited | Manufacturing | 1954 |
| Bloody Bridge Campsite Ltd | Hospitality | 2024 |
| Bloom Developments Group Ltd | Construction | 2026 |
| Blooming Brilliant Limited | Administrative & support | 2021 |
| Blooming Events Hire Limited | Other services | 2023 |
| Blooming Hel’S Limited | Wholesale & retail | 2024 |
| Blue Apricot Innovations Ltd | Professional & scientific | 2018 |
| Blue Flag Entertainment Limited | Wholesale & retail | 2017 |
| Blue Flame Certification Limited | Administrative & support | 2004 |
| Blue Oriel Limited | Other services | 2025 |
| Bluebear Retails Limited | Wholesale & retail | 2022 |
| Bluebell Wood Property Limited | Real estate | 2025 |
| Bluebell Wood Sales Ltd | Wholesale & retail | 2025 |
| BMG House Ltd | Hospitality | 2026 |
| BML BDS Ltd | Health & social care | 2022 |
| BO and Bean Ltd | Wholesale & retail | 2019 |
| Boarshurst Ltd | Health & social care | 2025 |
| Bobd Hair Supplies Ltd | Wholesale & retail | 2020 |
| Bobtechnologies Ltd | Wholesale & retail | 2025 |
| BOD Hyfryd Care Ltd | Health & social care | 2022 |
| Boden Roofing & Building Ltd | Construction | 2006 |
| Bohill Investments Ltd | Information & communication | 2004 |
| Boina Ltd | Wholesale & retail | 2021 |
| Boltway Investigations Limited | Administrative & support | 2011 |
| Bonney Field Livery Ltd | Agriculture & fishing | 2024 |
| Bookmyshift Ltd | Information & communication | 2023 |
| Boomerang Apps Ltd | Administrative & support | 2019 |
| Boomerang Recycling for Good CIC | Water & waste | 2025 |
| Born 2 Run Events Ltd | Arts & recreation | 2012 |
| Borys Transporter Ltd | Transport & logistics | 2021 |
| Bosley Builds Ltd | Construction | 2024 |
| Boss Sapphire Ltd | Hospitality | 2025 |
| Bossmanservices Limited | Health & social care | 2022 |
| Bourne Electrical Contractors Limited | Construction | 1995 |