| Better Home Living Limited | Wholesale & retail | 2018 |
| Better Lives - Strengthening Independence Ltd | Administrative & support | 1998 |
| Better Spirits Ltd | Wholesale & retail | 2020 |
| Bevan Radiology Ltd | Health & social care | 2025 |
| Beverage Bombs Ltd | Wholesale & retail | 2026 |
| BF Bakery Ltd | Hospitality | 2021 |
| Bfops Ltd | Hospitality | 2024 |
| BGC Properties Ltd | Real estate | 2020 |
| Bhamidipati Medical Services Ltd | Health & social care | 2022 |
| BHD Accounting Ltd | Professional & scientific | 2016 |
| BHG Nominee Co (2) Limited | Financial services | 2007 |
| Biba Property Management Ltd | Construction | 2013 |
| Bibim Limited | Hospitality | 2009 |
| Bicester Garage Limited | Wholesale & retail | 2007 |
| BID Public Sector Ltd | Administrative & support | 2025 |
| Biedaki Limited | Professional & scientific | 2025 |
| Bifb Ltd | Construction | 2026 |
| Big Hair Productions Ltd | Information & communication | 2024 |
| Big Stellar Ltd | Wholesale & retail | 2024 |
| Bigger Half Limited | Professional & scientific | 2023 |
| Bike Tyre Services Limited | Manufacturing | 2008 |
| Billerflax Holdings Limited | Financial services | 2019 |
| Billerflax Limited | Real estate | 1973 |
| Binarysphere Ltd | Information & communication | 2025 |
| Biocognita Ltd | Information & communication | 2025 |
| Biomass Consultants Ltd | Professional & scientific | 2013 |
| Biomed Consultancy Limited | Information & communication | 2014 |
| Biopod Ltd | Professional & scientific | 2021 |
| Bird & Pestworx Limited | Other services | 2019 |
| Birva Consultancy Ltd | Information & communication | 2019 |
| BJ Training & Consultancy Services Ltd | Education | 2016 |
| BJN Properties Ltd | Real estate | 2017 |
| BKB Group Services Ltd | Wholesale & retail | 2025 |
| BLA Creative Ltd | Construction | 2023 |
| Black Apron Ltd | Education | 2020 |
| Blackberry Wood Glamping (Sussex) Ltd | Hospitality | 2024 |
| Blackpool Road Ltd | Real estate | 2023 |
| Blackstar Creative Limited | Professional & scientific | 2019 |
| Blackstar Properties Limited | Real estate | 2016 |
| Blackstar Software Services Ltd | Professional & scientific | 2025 |
| BLD Common Lane Limited | Real estate | 2024 |
| Blend Centre Limited | Professional & scientific | 2015 |
| Blenheim Administration Limited | Professional & scientific | 2012 |
| Bletchley Technologies Limited | Administrative & support | 2016 |
| Bliss Salon Ltd | Other services | 2025 |
| Blissco Limited | Professional & scientific | 2025 |
| Bloc Building Consultancy Limited | Construction | 2020 |
| Bloc Uppermill Ltd | Hospitality | 2024 |
| Bloom Boom Ltd | Manufacturing | 2024 |
| Bloom Hair Company MCR Limited | Other services | 2022 |
| Bloor Renovations Limited | Construction | 2022 |
| Blue Bay Property Management Limited | Real estate | 2017 |
| Blue Chip Concierge Service Limited | Real estate | 2008 |
| Blue Flame Fire Engineering Ltd | Construction | 2024 |
| Blue Flowers Limited | Manufacturing | 2017 |
| Blue GEM Beauty Ltd | Health & social care | 2024 |
| Blue Moon Lettings Limited | Real estate | 2013 |
| Blue Moon Rising Limited | Wholesale & retail | 2026 |
| Blue Ribbon Cars Limited | Wholesale & retail | 2013 |
| Blue Stallion Ltd | Wholesale & retail | 2016 |
| Blueprint Electrical Services Limited | Construction | 2018 |
| Bluetec Systems Limited | Information & communication | 2015 |
| Blushed Homes Limited | Administrative & support | 2026 |
| Blutech Holdings Limited | Financial services | 2021 |
| Bmac Consulting Ltd | Professional & scientific | 2020 |
| BNJ Global Limited | Transport & logistics | 2022 |
| Boathouse (Sale) Limited | Hospitality | 2012 |
| Boba LAB Ltd | Wholesale & retail | 2018 |
| Boccard UK Limited | Construction | 1974 |
| Bodyco Limited | Extraterritorial | 2016 |
| Bodytech Automotive Limited | Wholesale & retail | 2014 |
| Bonbon RP Limited | Real estate | 2025 |
| Boneyemm Ltd | Hospitality | 2023 |
| Bonkers Prices Ashton Ltd | Wholesale & retail | 2023 |
| Bookhook Ltd | Wholesale & retail | 2026 |
| Booming Technologies Limited | Information & communication | 2018 |
| Boothroyd House Ltd | Households | 2024 |
| Bordercharge Ltd | Professional & scientific | 2026 |
| Boston West (Holdings) Limited | Financial services | 2012 |
| Boulevard MCD Ltd | Real estate | 2025 |
| Bountiful Ventures Ltd | Wholesale & retail | 2024 |
| Boutique Event Hire Ltd | Hospitality | 2018 |
| Bowden Building Projects Limited | Construction | 2025 |
| Bowdon Associates Ltd | Administrative & support | 2021 |
| Bowdon Property Lettings Ltd | Real estate | 2021 |
| Bowdon Property Management Ltd | Real estate | 2015 |
| Bower CE Limited | Professional & scientific | 2023 |
| Bowman Wilson Holdings Limited | Professional & scientific | 2025 |
| Bowman Wilson Limited | Manufacturing | 2017 |
| Bowmay Consulting Ltd | Administrative & support | 2017 |
| Bownass & Gibb Limited | Real estate | 2009 |
| Box Red Limited | Wholesale & retail | 2025 |
| Boxed OFF TV Ltd | Information & communication | 2024 |
| Boxfellas Ltd | Wholesale & retail | 2025 |
| Bpdunne Engineering Limited | Construction | 2015 |
| BPP Group Limited | Real estate | 2015 |
| BPW Services Limited | Professional & scientific | 2003 |
| Brackman Wolfe & Company Limited | Professional & scientific | 1995 |
| Bradbury Coulthard Limited | Professional & scientific | 2025 |
| Braemoir Services Limited | Information & communication | 2007 |