| Beverley & Williams Accountants Ltd | Professional & scientific | 2003 |
| BEX 8 Limited | Wholesale & retail | 2024 |
| BEX Vapes Limited | Wholesale & retail | 2023 |
| Bexx Ltd | Wholesale & retail | 2025 |
| Beynon Films Ltd | Information & communication | 2019 |
| Beynon House Ltd | Hospitality | 2026 |
| Beyond the Binary Community Services C.I.C. | Administrative & support | 2022 |
| Beyond the Binary Ltd | Education | 2022 |
| BEYOND11 Technology Limited | Information & communication | 2025 |
| Bfpp Limited | Real estate | 2025 |
| BFS Associates Ltd | Professional & scientific | 2012 |
| BG Accountancy Services Limited | Professional & scientific | 2009 |
| BG Consult Limited | Professional & scientific | 2012 |
| BH Events and Experiences Ltd | Other services | 2018 |
| BH11 Media Limited | Administrative & support | 2018 |
| Bhalla Douglas Property Partners Limited | Real estate | 2016 |
| BHS Traders Ltd | Real estate | 2020 |
| BHSPROPERTIES24 Ltd | Real estate | 2025 |
| Biblical Sounds Ltd | Administrative & support | 2023 |
| Bid-It Services Ltd | Information & communication | 2024 |
| Bidaid Limited | Administrative & support | 2015 |
| Bidtech Limited | Information & communication | 2018 |
| Big Cat Productions Limited | Information & communication | 2016 |
| Big Wits Limited | Information & communication | 2024 |
| Bigboytenders Limited | Information & communication | 2025 |
| Biggapan Ltd | Information & communication | 2023 |
| Bigglestone Planning Services Ltd | Administrative & support | 2025 |
| Bikonic Limited | Wholesale & retail | 2014 |
| Bilben Estates Limited | Construction | 1971 |
| Bilbob Limited | Administrative & support | 2017 |
| Bill Mata 8 Limited | Arts & recreation | 2023 |
| Billingham Manor Estate Ltd | Agriculture & fishing | 2025 |
| BIM Designs Limited | Professional & scientific | 2011 |
| Bimbling Cottage Ltd | Hospitality | 2023 |
| Bindrule Limited | Households | 1973 |
| Biometrics Limited | Manufacturing | 1997 |
| Biomimetix Ltd | Professional & scientific | 2025 |
| Bipv Limited | Manufacturing | 2013 |
| Birchgrove Stores Ltd | Wholesale & retail | 2023 |
| Birchley Consultancy Limited | Construction | 2021 |
| Birdsong Design and Education Ltd | Professional & scientific | 2026 |
| Biro Cars UK Ltd | Wholesale & retail | 2000 |
| Bishopgate Homes Limited | Real estate | 2006 |
| Bishopsgate Resources Limited | Wholesale & retail | 2012 |
| Bishopston Compliance Limited | Administrative & support | 2018 |
| Bishpool Property Services Limited | Construction | 2025 |
| Bishton Properties Limited | Real estate | 2005 |
| Bisley Direct Limited | Wholesale & retail | 2016 |
| Bisley Office Equipment Limited | Professional & scientific | 1961 |
| Bisley Office Furniture Limited | Professional & scientific | 1986 |
| Bisnat Group Ltd | Real estate | 2019 |
| Bissell Commercial Services Limited | Administrative & support | 2014 |
| Bittersweet Promotion Bristol Limited | Administrative & support | 2015 |
| Bittersweet Promotion Cardiff Limited | Administrative & support | 2015 |
| Bizenia Enterprise Ltd | Health & social care | 2025 |
| BJJ Trading Ltd | Wholesale & retail | 2025 |
| BK15 Promotions Limited | Arts & recreation | 2018 |
| BL Contractors Ltd | Construction | 2018 |
| Black & Co. Consulting Ltd | Extraterritorial | 2019 |
| Black Abacus Limited | Real estate | 2016 |
| Black Brick City Ltd | Real estate | 2023 |
| Black Cherry Publishing Ltd | Information & communication | 2020 |
| Black Cherry Tattoo Limited | Other services | 2019 |
| Black Clawson Limited | Manufacturing | 2000 |
| Black Knight Education,Training and Management Ltd | Education | 2025 |
| Black Lion RH Ltd | Hospitality | 2025 |
| Black Lodge Property Ltd | Real estate | 2022 |
| Black Sand (Asset Management) Limited | Professional & scientific | 2017 |
| Blackbarn Flooring Limited | Wholesale & retail | 2015 |
| Blackdot Limited | Professional & scientific | 2007 |
| Blacker Heating Solutions Limited | Construction | 2025 |
| Blackhorse Housing Ltd | Real estate | 2022 |
| Blackmere Properties Ltd | Real estate | 2025 |
| Blacksquare Property Solutions Limited | Real estate | 2022 |
| Blackstone Civils Ltd | Professional & scientific | 2021 |
| Blackthorn Cabs L.P. | | 2006 |
| Blackvein Asset Management Limited | Professional & scientific | 2022 |
| Blackvein Circuits Limited | Manufacturing | 2017 |
| Blackwater House Residents RTM Company Limited | Households | 2009 |
| Blackwater Manor Limited | Households | 2011 |
| Blackwindow Group Ltd | Professional & scientific | 2023 |
| Blackwood Corporation Limited | Real estate | 2024 |
| Blade Repair Global Ltd | Manufacturing | 2022 |
| Blaiddrwg Limited | Information & communication | 2019 |
| Blaide’S Bits Ltd | Wholesale & retail | 2025 |
| Blake's Estates Ltd | Real estate | 2020 |
| Blakemore's Removals & Storage Limited | Transport & logistics | 2017 |
| Blanc Interior Design Ltd | Manufacturing | 2021 |
| Blanchards (IW) Management Company Ltd | Households | 2021 |
| Blanket World Ltd | Wholesale & retail | 2024 |
| Blas at Fronlas Limited | Hospitality | 2023 |
| Blazing Dough Limited | Hospitality | 2023 |
| Bleddyn Construction Ltd | Construction | 2018 |
| Blenheim Accounting Limited | Professional & scientific | 2002 |
| Blessed Beauty Group Ltd | Other services | 2022 |
| Blessed Beauty Ltd | Other services | 2023 |
| Blingz Blingz Nails Beauty Limited | Other services | 2025 |
| Bliss Ice Cream Limited | Extraterritorial | 2020 |
| BLITTER8 Limited | Information & communication | 2012 |
| BLK Scaffolding Ltd | Construction | 2025 |