| Bimm University Limited | Education | 2007 |
| Binary Media Limited | Information & communication | 2010 |
| Biológica Aesthetics Ltd | Other services | 2022 |
| Birchwood Dental Associates Ltd | Health & social care | 2019 |
| Bisa Ltd | Professional & scientific | 2024 |
| Bishop & Light Solicitors Limited | Professional & scientific | 2008 |
| Bishop Calway Insurance Services Limited | Financial services | 2002 |
| Bitbrush Ltd | Professional & scientific | 2019 |
| Bite the Bullet Projects Ltd | Real estate | 2025 |
| Bite the Movie Ltd | Administrative & support | 2015 |
| Bitwise Software Ltd | Information & communication | 2018 |
| BIZ123 International Limited | Professional & scientific | 2018 |
| BJT Investments Ltd | Real estate | 2023 |
| BKG Solutions Limited | Administrative & support | 2024 |
| Black Bear Property Limited | Real estate | 2019 |
| Black Cherry Films Limited | Information & communication | 2019 |
| Black OPS Electric Ltd | Construction | 2020 |
| Black OR White Food Services Ltd | Hospitality | 2022 |
| Black Swan Capital Ltd | Financial services | 1999 |
| Blackburn Print Limited | Manufacturing | 1974 |
| Blackchain Limited | Wholesale & retail | 2024 |
| Blackout Deck Ltd | Wholesale & retail | 2023 |
| Blackstone Cafes Ltd | Hospitality | 2025 |
| Blaid Scaffolding, Plant and Equipment Limited | Construction | 2008 |
| Blaid Southern Limited | Construction | 2014 |
| Blair Records and Publishing Limited | Information & communication | 2024 |
| Blair Reputation Management Ltd | Professional & scientific | 2025 |
| Blanco Brothers Ltd | Arts & recreation | 2024 |
| Blankads Ltd | Professional & scientific | 2026 |
| Blankfrank Creative Limited | Information & communication | 2013 |
| Blatchington Court Nominee Limited | Professional & scientific | 1994 |
| Blatchington Launderette Ltd | Other services | 2022 |
| Blatchington Property Express Ltd | Real estate | 2019 |
| Blatchington Road (Hove) Limited | Real estate | 2022 |
| Blatchington Road Flooring Ltd | Wholesale & retail | 2021 |
| Blatchnor Residents Association Limited | Real estate | 2017 |
| Bleak House ST Albans Management Company Ltd | Households | 2004 |
| Blend & Brew Brighton Ltd | Hospitality | 2016 |
| Blend & Brew Holdings Ltd | Real estate | 2024 |
| Blendal Limited | Real estate | 1989 |
| Blenheim Court Hove RTM Company Limited | Extraterritorial | 2026 |
| Blessed Wines Ltd | Professional & scientific | 2025 |
| Blind Colour Limited | Information & communication | 2012 |
| Blind PIG Tattoo Club Limited | Other services | 2015 |
| Blipaudio Ltd | Arts & recreation | 2014 |
| Blippublishing Ltd | Information & communication | 2021 |
| Bliptrax Ltd | Information & communication | 2023 |
| Bliss City Limited | Real estate | 2024 |
| BLM Merchandise Ltd | Wholesale & retail | 2025 |
| Block a 9 the Upper Drive Limited | Households | 2023 |
| Block B 9 the Upper Drive Limited | Households | 2023 |
| Block Management Solutions - Client - Limited | Households | 2023 |
| Block Management Solutions South Limited | Real estate | 2026 |
| Blockbuilders C.I.C. | Education | 2014 |
| Blockbuilders Youth Engagement Ltd | Education | 2020 |
| Blood Systems Limited | Information & communication | 2021 |
| Bloodstock Investments Ltd | Administrative & support | 2007 |
| Bloodstock Merchandise Ltd | Wholesale & retail | 2026 |
| Blossom Hill Cleaning Services Limited | Administrative & support | 2024 |
| Blue Lionfish Consulting Limited | Financial services | 2014 |
| Blue Lotus Consulting Limited | Information & communication | 2023 |
| Blue PEG Recruitment Limited | Administrative & support | 2017 |
| Blue Sky Town Limited | Real estate | 2025 |
| Blue Sphere Property Investments Ltd | Real estate | 2021 |
| Blue Stays Brighton Ltd | Real estate | 2024 |
| Blue Swan Outsourcing Ltd | Administrative & support | 2013 |
| Blue Wave Property Management Ltd | Real estate | 2021 |
| Bluebirds Interiors Limited | Construction | 2020 |
| Bluegates Solar Limited | Energy | 2013 |
| Bluehouse Cleaning Services Ltd | Administrative & support | 2024 |
| Bluejay Estates Limited | Real estate | 2020 |
| Blueprint Exhibitions and Conferences Limited | Administrative & support | 2023 |
| Blueridge Roofing Services Ltd | Construction | 2025 |
| Blues Point Finance Ltd | Financial services | 2013 |
| BLUESEVEN111 Limited | Financial services | 2016 |
| Bluesilver Limited | Professional & scientific | 2025 |
| Bluestone South West Scaffolding Limited | Construction | 2024 |
| Bluetec DS Limited | Health & social care | 2019 |
| Bluewave Geographics Limited | Professional & scientific | 2012 |
| BLX Hastings Ltd | Construction | 2025 |
| BLX Minster Ltd | Construction | 2023 |
| BM Dental Limited | Health & social care | 2023 |
| Bmcic UK Limited | Wholesale & retail | 2017 |
| BMR Consultancy Services Ltd | Financial services | 2009 |
| Bmsm Group Limited | Financial services | 2025 |
| BN1 Events Collective Ltd | Arts & recreation | 2023 |
| BN1 Property Maintenance Ltd | Construction | 2022 |
| BN1SPORTS Limited | Arts & recreation | 2009 |
| BN2 3HJ Ltd | Real estate | 2021 |
| BN2 3HJ SPV 2 Limited | Real estate | 2026 |
| BN3 Events Ltd | Other services | 2025 |
| BN3 Works Ltd | Professional & scientific | 2026 |
| BO Style Limited | Other services | 2018 |
| Boaks Property Management Ltd | Administrative & support | 2025 |
| Boao Media Limited | Information & communication | 2026 |
| Boarer Pest Control Ltd | Other services | 2018 |
| Bobel Castle Limited | Real estate | 2019 |
| Bodacious Engineering Ltd | Professional & scientific | 2012 |
| Bodhisattva Kadampa Meditation Centre | Other services | 1992 |
| Bodwen Solar Project Limited | Energy | 2013 |