| Boulter Property Investment & Management Limited | Real estate | 2017 |
| Bourne Taylor Neville Limited | Administrative & support | 1987 |
| BOW Meadow Wilsons Lane Coventry Residents Management Company Limited | Households | 2026 |
| Bower Manor (Bridgwater) Management Limited | Real estate | 1993 |
| Boxpoint Ltd | Professional & scientific | 2024 |
| Boyson Healthcare Ltd. | Health & social care | 2014 |
| BQ MED Ltd | Health & social care | 2026 |
| Bradford Court Residents Management Company Limited | Other services | 2009 |
| Bradshaw Cooper Consulting Ltd | Professional & scientific | 2025 |
| Brahma Holdings Limited | Real estate | 2022 |
| Brahma Property Investments Limited | Real estate | 2019 |
| Brahma Property Solutions Ltd | Administrative & support | 2017 |
| Bramble Dining Ltd | Hospitality | 2020 |
| Brand Company UK Global Ltd | Wholesale & retail | 2026 |
| Brand Metrics UK Limited | Information & communication | 2020 |
| Brandhub Limited | Real estate | 2009 |
| Brandon Merchandising UK Ltd | Administrative & support | 2025 |
| Brandon Thatchers Limited | Construction | 2019 |
| Brasspress Ltd | Transport & logistics | 2021 |
| Brazil Construction Limited | Construction | 2015 |
| Brazil Tech Connect | Information & communication | 2025 |
| Bread & Co. (Retail) Limited | Manufacturing | 2008 |
| Breaking Frontiers Limited | Professional & scientific | 2006 |
| Breathe Production Ltd | Wholesale & retail | 2003 |
| Breezy Developments Ltd | Real estate | 2021 |
| Brick Slip Systems Ltd | Manufacturing | 2025 |
| Bridge ROW Corner Management Ltd. | Households | 2023 |
| Bridge Street Communications Limited | Professional & scientific | 2007 |
| Bridge Street Pets Ltd | Wholesale & retail | 2022 |
| Bridgeabl Limited | Financial services | 2021 |
| Bridgestone Mining Solutions Technology Limited | Information & communication | 2020 |
| Bridgestone Retail UK Limited | Wholesale & retail | 2013 |
| Bridgeway Express Parcels Ltd | Transport & logistics | 2012 |
| Briefmine Limited | Real estate | 1988 |
| Bright IT Solutions Ltd | Other services | 2019 |
| Brightcap Consulting Limited | Transport & logistics | 2019 |
| Brightstrike Limited | Administrative & support | 2021 |
| Brightwater Design & Build Limited | Real estate | 2024 |
| Brilliant Minds Training & Development Limited | Professional & scientific | 1997 |
| Britech Telecom Limited | Information & communication | 2023 |
| British European Aviation Limited | Wholesale & retail | 2010 |
| Britrealm Ltd | Wholesale & retail | 2025 |
| Brits Kenilworth Limited | Other services | 2015 |
| Brits Leamington Limited | Other services | 2015 |
| Brits Warwick Limited | Other services | 2019 |
| Brixhire Limited | | 1979 |
| BRK Manufacturing Limited | Professional & scientific | 2026 |
| BRO Drinks Ltd | Wholesale & retail | 2019 |
| Broadband Rentals Ltd | Information & communication | 2024 |
| Broadview Farm Cottages Ltd | Construction | 2024 |
| Broadview Farm Limited | Other services | 2021 |
| Broadwater Global Talent Ltd | Other services | 2025 |
| Brockbank Ltd | Administrative & support | 2008 |
| Bromfield Consulting Limited | Professional & scientific | 2025 |
| Brooke Mews Management Company Limited | Other services | 2003 |
| Brooks Properties Ltd | Real estate | 2016 |
| Broquila Limited | Wholesale & retail | 2024 |
| Broski Whisky Limited | Wholesale & retail | 2023 |
| Browseman Limited | Financial services | 2024 |
| BRS Limited | Administrative & support | 1998 |
| Bruno & Daughters Transport Ltd | Transport & logistics | 2024 |
| Bryer Estates Holdings Limited | Extraterritorial | 2017 |
| Bryer Estates Limited | Agriculture & fishing | 2017 |
| Bryher Property Limited | Construction | 2022 |
| Bryn Arden Management Limited | Households | 2003 |
| Bryn Housing Ltd | Real estate | 2019 |
| Bryta Investments Limited | Financial services | 2022 |
| BSF Midlands Ltd | Health & social care | 2023 |
| BSS Engineering Limited | Professional & scientific | 2013 |
| BSS Installations Limited | Information & communication | 2014 |
| BTI Greentec Ltd. | Information & communication | 2021 |
| Buckhold Property Ltd | Real estate | 2023 |
| Buckingham Fine Art Publishers Limited | Information & communication | 1982 |
| Budbrooke Estate Tree Surgery Ltd | Administrative & support | 2025 |
| Budbrooke Point (Management) Ltd | Real estate | 2012 |
| Budbrooke Signs Limited | Manufacturing | 2003 |
| Budulan Tech Limited | Professional & scientific | 2014 |
| Buffer Bear Limited | Education | 1994 |
| Build and Conquer CIC | Education | 2022 |
| Build and Conquer Impact Academy Ltd | Education | 2025 |
| Build Flow Construction and Carpentry Ltd | Manufacturing | 2026 |
| Build Hub Group Limited | Professional & scientific | 2025 |
| Build Hub Leads Limited | Professional & scientific | 2024 |
| Build Hub Limited | Administrative & support | 2024 |
| Build My Gift Ltd | Wholesale & retail | 2017 |
| Buildage Limited | Construction | 2017 |
| Buildcraft Developments Ltd | Construction | 2020 |
| Builtec Developments Limited | Construction | 1972 |
| Bulk Fiber Networks UK Limited | Administrative & support | 2019 |
| Bulk Infrastructure UK Limited | Information & communication | 2019 |
| Bull Oak Property Limited | Real estate | 2011 |
| Bull Ring Trading Estate Limited | Real estate | 2017 |
| Bulldog Design Solutions Limited | Professional & scientific | 2014 |
| Bulldog Joinery & Interiors LLP | | 2006 |
| Bulldog Remoulds Limited | Manufacturing | 1968 |
| Bullfix Ltd | Manufacturing | 2018 |
| Bunji Limited | Manufacturing | 2020 |
| Bunk Housing Limited | Real estate | 2018 |
| Burkin & Partners Financial Planning Ltd | Financial services | 2023 |
| Burleigh Limited | Financial services | 2017 |