| Bluebridge Construction Limited | Construction | 2014 |
| Bluebuzzard Limited Limited | Real estate | 2023 |
| Bluecyte Ltd | Administrative & support | 2018 |
| Bluefish Capital Limited | Professional & scientific | 2026 |
| Bluelearning Ltd | Education | 2023 |
| Blueprint Consulting Services Limited | Professional & scientific | 2023 |
| Blueridge Roofing and Building Ltd | Construction | 2023 |
| Bluestone Biogas Limited | Energy | 2024 |
| Bluevue Property Ltd | Real estate | 2023 |
| Bluewater Falls Limited | Wholesale & retail | 2021 |
| Blush Brand Consulting Ltd | Professional & scientific | 2018 |
| Blushy Mineral Ltd | Wholesale & retail | 2026 |
| Blusparc Services Limited | Professional & scientific | 2016 |
| BMI Publishing Limited | Information & communication | 1991 |
| Bmji Ltd | Financial services | 2026 |
| BNS Media Productions Ltd | Information & communication | 2023 |
| Board Direction Limited | Professional & scientific | 2004 |
| BOB Sign Language Action CIC | Education | 2014 |
| BOB Sign Language Ltd | Education | 2014 |
| Bobboire Holdings Ltd | Financial services | 2025 |
| Bodyfodder Limited | Wholesale & retail | 2018 |
| BOG Busters Facilities Limited | Construction | 2010 |
| BOG Busters Limited | Construction | 2024 |
| Bohica Investments Limited | Wholesale & retail | 1992 |
| Bolistrom Limited | Financial services | 1993 |
| Bombay Buzz UK Ltd | Hospitality | 2019 |
| Bond Ceramics Ltd | Wholesale & retail | 2006 |
| Bones Workshop Ltd | Professional & scientific | 2024 |
| Bongbong Limited | Health & social care | 2022 |
| Boomwall Limited | Extraterritorial | 2012 |
| Boon Group Limited | Financial services | 2012 |
| Boon Property Services Ltd | Real estate | 2013 |
| Borg Pharma Limited | Wholesale & retail | 2007 |
| Borrowed Breath Limited | Professional & scientific | 2021 |
| Boss Games Limited | Information & communication | 2016 |
| Bosunmark Limited | Professional & scientific | 1986 |
| Botin Industry Ltd | Wholesale & retail | 2025 |
| Bottle Bond Limited | Administrative & support | 2025 |
| Bottle Books Limited | Information & communication | 2015 |
| Bourne Brothers Ltd | Wholesale & retail | 2024 |
| Bourne International Limited | Wholesale & retail | 1985 |
| Boustead Ventures Limited | Professional & scientific | 1997 |
| Boutique on the Hill Ltd | Wholesale & retail | 2024 |
| Boving Engineering UK Limited | Construction | 2000 |
| Bowden Data Ltd | Information & communication | 2025 |
| Bowen Publishing Ltd | Extraterritorial | 2004 |
| Bower Wood Production Services Ltd | Arts & recreation | 2021 |
| Bowes Lyon Partnership Limited | Other services | 2009 |
| Bowlyn Style Ltd | Wholesale & retail | 2011 |
| Boxgrove Financial Consulting Ltd | Professional & scientific | 2026 |
| Boxgrove House (Residents) Association Limited | Households | 1981 |
| BOY Entertainment Ltd | Real estate | 2019 |
| Boyce, Brown & Wilson Limited | Manufacturing | 1978 |
| BPA Fitness Limited | Education | 2023 |
| BPC Properties Ltd | Real estate | 2005 |
| Brabo Invest Ltd | Financial services | 2021 |
| Brachytherapy Expert Limited | Health & social care | 2024 |
| Brackendale Tree Care Limited | Agriculture & fishing | 2015 |
| Bracknell Overage | | 2009 |
| Bradshaw Land Limited | Real estate | 2013 |
| Bradstone Brook Management Company Limited | Households | 2004 |
| Braecroft Residents Association Limited | Households | 1999 |
| Braganza Court (Guildford) Residents Association Limited | Households | 1965 |
| Brahmani Home Limited | Manufacturing | 2025 |
| Brain-Ea Ltd | Information & communication | 2009 |
| Brambles Estate Residents Management Company Limited | Households | 1973 |
| Bramley Fete Limited | Administrative & support | 2025 |
| Bramley Glass Limited | Construction | 1995 |
| Bramley Golf Club Limited | Arts & recreation | 2020 |
| Bramley Investment Holdings Limited | Construction | 2001 |
| Bramley Motor Cars Limited | Extraterritorial | 2013 |
| Bramley Window Systems Limited | Construction | 1995 |
| Bramley Windows Limited | Professional & scientific | 1998 |
| Brancaster Consulting Ltd | Professional & scientific | 2026 |
| Brand ADB Limited | Wholesale & retail | 2026 |
| Brand ERA Limited | Professional & scientific | 2014 |
| Brand Legacy Consultancy Limited | Professional & scientific | 2015 |
| Brand Legacy Limited | Professional & scientific | 2007 |
| Brand Reputation Compliance Limited | Professional & scientific | 2016 |
| Brand-Live Limited | Professional & scientific | 2012 |
| Brand-Live Property Investment Limited | Real estate | 2021 |
| Brands From Africa Ltd | Wholesale & retail | 2020 |
| Brantome Ltd | Professional & scientific | 2025 |
| Brave Beyond Ltd | Professional & scientific | 2019 |
| Bravomonster Limited | Wholesale & retail | 2024 |
| Brazilian Green Beans Ltd | Extraterritorial | 2021 |
| BRC Trading Limited | Professional & scientific | 2001 |
| Breakline Ltd | Information & communication | 2018 |
| Brethren Apparel Ltd | Wholesale & retail | 2013 |
| Brett Vorley Management Limited | Real estate | 2011 |
| Brian Carter Ltd | Financial services | 2019 |
| Brian Noble Limited | Professional & scientific | 2015 |
| Brick and Bloom Publishing Limited | Information & communication | 2025 |
| Brickfield Consulting Ltd | Professional & scientific | 2017 |
| Bricksave for Koodos Limited | Professional & scientific | 2026 |
| Brickslab Edison CIC | Education | 2025 |
| Bridge ING Ltd | Professional & scientific | 2023 |
| Bridge Lane Developments Limited | Construction | 2003 |
| Bright Light PR Limited | Professional & scientific | 2008 |
| Bright Sky Business Ltd | Administrative & support | 2018 |