| Berkeley Financial Partners Ltd | Financial services | 2014 |
| Berkeley Integra Limited | Construction | 1995 |
| Berncare Services Ltd | Administrative & support | 2014 |
| Berry Creative Ltd | Professional & scientific | 2025 |
| Bertrands Healthcare Ltd | Health & social care | 2019 |
| Beskco Ltd | Wholesale & retail | 2019 |
| Bespoke Builds Limited | Construction | 2023 |
| Bespoke Handling Ltd | Transport & logistics | 2014 |
| Bespoke Home Care Limited | Other services | 2011 |
| Bespoke Sports & Performance Cars Limited | Other services | 2014 |
| Bespoke Surveying Services Ltd | Professional & scientific | 2014 |
| Best One Hand Car Wash Ltd | Professional & scientific | 2025 |
| Best Practice CDA Limited | Health & social care | 2009 |
| Best Practice People Limited | Administrative & support | 2011 |
| Best Quality Healthcare Limited | Health & social care | 2024 |
| Bestoflondonmusic Ltd | Information & communication | 2006 |
| BET (NO. 18) Limited | Extraterritorial | 1976 |
| BET (NO. 68) Limited | Professional & scientific | 1967 |
| BET Environmental Services Ltd | Professional & scientific | 1928 |
| BET Pension Trust Limited | Extraterritorial | 1965 |
| Beta Comms Ltd | Administrative & support | 2006 |
| Bevcar Ltd | Education | 2022 |
| Bewbush Community Nursery C.I.C. | Health & social care | 2012 |
| Bewbush Dental Limited | Health & social care | 2015 |
| Beyond Countdown Limited | Professional & scientific | 2025 |
| BFG Global Ltd | Administrative & support | 2020 |
| Bfse Trading Ltd | Construction | 2024 |
| BGL Communications Ltd | Administrative & support | 2010 |
| BH Skills and Training Ltd | Education | 2026 |
| Bhaiyaji Chat House Limited | Hospitality | 2025 |
| Bholenath 2024 Limited | Wholesale & retail | 2024 |
| Bholenath Properties Limited | Real estate | 2026 |
| Bhoya Limited | Health & social care | 2023 |
| Bhugs Home Ltd | Real estate | 2025 |
| BHV Properties Ltd | Real estate | 2023 |
| BHW Automotive Limited | Wholesale & retail | 2004 |
| Biadav Limited | Professional & scientific | 2018 |
| Bibbey Properties Limited | Real estate | 2024 |
| Bidco 33 Limited | Real estate | 2023 |
| Biemp Ltd | Other services | 2017 |
| Big Bolt Limited | Wholesale & retail | 1973 |
| Big Box Property Group Ltd | Construction | 2021 |
| Big Box Property Holdings Ltd | Financial services | 2025 |
| Big Bull IT Limited | Information & communication | 2013 |
| Big Four Construction Limited | Construction | 2020 |
| Big Impact Ltd | Information & communication | 2025 |
| Big Little Moves Ltd | Real estate | 2021 |
| Bigbox Properties Limited | Real estate | 2021 |
| Biggs Estates Ltd | Real estate | 2026 |
| Bilir Food Ltd | Hospitality | 2019 |
| Billa Traders Ltd | Administrative & support | 2023 |
| Billy's Simple Kitchen Limited | Hospitality | 2022 |
| Binary Motions Limited | Information & communication | 2017 |
| Binary OPS Ltd | Information & communication | 2023 |
| Bindal Investments Limited | Education | 2004 |
| Bings Design Ltd | Information & communication | 2020 |
| Binwa Fashion Ltd | Wholesale & retail | 2024 |
| BIO Products Validation Limited | Professional & scientific | 2016 |
| Biology Healthcare Limited | Health & social care | 2019 |
| Biopretium Ltd | Administrative & support | 2024 |
| Biorevive Ltd | Wholesale & retail | 2024 |
| Birch People Consulting Ltd | Professional & scientific | 2024 |
| Birchwood Consultancies Ltd | Information & communication | 2017 |
| Bird Nest Properties Limited | Real estate | 2022 |
| Birdie First Ltd | Real estate | 2024 |
| Birk & Co Properties Ltd | Real estate | 2023 |
| Biro-Smart Properties Ltd | Real estate | 2019 |
| Birthrite Mentors Ltd | Education | 2021 |
| Bishops & Haig Limited | Manufacturing | 2026 |
| Bishops French Polishing Ltd | Construction | 2023 |
| Bismi Care Limited | Health & social care | 2022 |
| Bitbridge Ltd | Wholesale & retail | 2026 |
| Bitch Productions Limited | Information & communication | 2001 |
| Bite & Feast Limited | Hospitality | 2026 |
| Bite and Draught Limited | Hospitality | 2024 |
| Bizwiseit LLP | | 2004 |
| BJ (1) Limited | Professional & scientific | 1996 |
| BJC Automotive Repairs Ltd | Wholesale & retail | 2025 |
| BJM Global Consultancy Ltd | Professional & scientific | 2019 |
| BK Events Limited | Professional & scientific | 2009 |
| Bkjs Developments Ltd | Construction | 2022 |
| Bkjs Holdings Ltd | Financial services | 2022 |
| Black 22 Bars and Restaurants Limited | Extraterritorial | 2007 |
| Black 22 Group Limited | Administrative & support | 2007 |
| Black Habit Limited | Manufacturing | 2023 |
| Black Rose Gardening Limited | Administrative & support | 2023 |
| Black-Tied Ltd | Information & communication | 2025 |
| Blackdown Close Management Company Limited | Households | 2012 |
| Blacks in Boardrooms Limited | Administrative & support | 2016 |
| Blackshaw Tech Ltd | Information & communication | 2026 |
| Blacksmith Products Limited | Wholesale & retail | 2005 |
| Blackstone Construction South East Ltd | Construction | 2024 |
| Blackthorn Carpentry Ltd | Construction | 2025 |
| Blades Hair & Beauty (Sussex) Limited | Other services | 2008 |
| Blairmore Wealth Limited | Professional & scientific | 2024 |
| Blake Marine Ltd | Professional & scientific | 2016 |
| Blakeley Plumbing Services Ltd | Construction | 2020 |
| Blakemore Consultants Ltd | Real estate | 2003 |
| BLB Property Coaching Limited | Education | 2025 |
| Bless Textiles Limited | Manufacturing | 2026 |