| Birks London Limited | Hospitality | 2015 |
| Birmingham Living Ltd | Real estate | 2025 |
| Bisade Cake Atelier Ltd | Manufacturing | 2025 |
| Bishman Property Management Limited | Real estate | 1991 |
| Bishop & Koranteng Limited | Professional & scientific | 2024 |
| Bishophouse Limited | Professional & scientific | 2004 |
| Bishops Green (Derby) Limited | Households | 2004 |
| Bishops Keep Block a Management Limited | Households | 2008 |
| Bishops Park (Number 1) Management Company Limited | Households | 2002 |
| Bishops Park (Number 2) Management Company Limited | Households | 2002 |
| Bishops Park (Number 4) Management Company Limited | Households | 2002 |
| Bishops Wine Bar Ltd | Hospitality | 2012 |
| Bisla Real Estates Limited | Wholesale & retail | 2023 |
| Bismillah Foods Giant Ltd | Hospitality | 2012 |
| Bista Homes Ltd | Real estate | 2021 |
| BIT Kanvas Limited | Information & communication | 2026 |
| Bite & Grill Ltd | Hospitality | 2026 |
| Bite & SIP Limited | Wholesale & retail | 2025 |
| Biter's Limited | Hospitality | 2018 |
| Bits and Bobs by V Ltd | Wholesale & retail | 2024 |
| Bits N Bytes Solutions Ltd | Wholesale & retail | 2014 |
| Bitsec International Ltd | Information & communication | 2020 |
| Bitveil Ltd | Information & communication | 2025 |
| Bitz for ALL Limited | Wholesale & retail | 2018 |
| Bizanova Limited | Professional & scientific | 2018 |
| Bizav Media Limited | Information & communication | 2016 |
| Bizness Doctor Limited | Administrative & support | 2022 |
| Bizoso Consulta Limited | Professional & scientific | 2025 |
| Bizzotto & Lago LLP | | 2018 |
| Bjewelicious Ltd | Manufacturing | 2023 |
| Bjlt Limited | Construction | 2010 |
| BJP Invest Ltd | Real estate | 2025 |
| BK Electrical.Com (London) Limited | Construction | 2016 |
| BK Global Resources Limited | Health & social care | 2019 |
| BK Homes Limited | Construction | 2016 |
| Bk&M Properties Limited | Real estate | 2025 |
| BK21 Limited | Arts & recreation | 2021 |
| BKD Construction Ltd | Professional & scientific | 2023 |
| Bkdrops Ltd | Other services | 2025 |
| BKT Retail Limited | Wholesale & retail | 2023 |
| Bktooting Co Limited | Hospitality | 2025 |
| Bkvs Events Ltd | Other services | 2026 |
| BL Vision Ltd | Wholesale & retail | 2026 |
| BL. Engineering Services Ltd | Manufacturing | 2018 |
| Blaby News Limited | Wholesale & retail | 2017 |
| Black Cat Productions Limited | Manufacturing | 2025 |
| Black Diamond Support Limited | Wholesale & retail | 2016 |
| Black GECK0 Ltd | Information & communication | 2024 |
| Black Heroes in the Hall of Fame Limited | Arts & recreation | 2024 |
| Black Horse Inn Management Limited | Real estate | 2005 |
| Black in Fintech Ltd | Professional & scientific | 2025 |
| Black Labs London Ltd | Manufacturing | 2020 |
| Black Lily Ltd | Information & communication | 2023 |
| Black Line Services Ltd | Administrative & support | 2025 |
| Black Lion Workshops Limited | Wholesale & retail | 2021 |
| Black MMM Ltd | Construction | 2026 |
| Black Phoenix Property Limited | Real estate | 2025 |
| Black Shardana Ltd | Professional & scientific | 2021 |
| Black Spectre Entertainment Ltd | Arts & recreation | 2023 |
| Black Spin Global Ltd | Wholesale & retail | 2024 |
| Blackbird of Sussex Ltd | Wholesale & retail | 2024 |
| Blackbird Trading Limited | Administrative & support | 2012 |
| Blackbridge Lane Residents Association Limited | Households | 2012 |
| Blackbright Ltd | Wholesale & retail | 2012 |
| Blackfriars Steel and Aluminium Fabrication Limited | | 1981 |
| Blackhabit Media Limited | Manufacturing | 2025 |
| Blackheath Butchers Limited | Wholesale & retail | 2023 |
| Blackheath Eyecare Limited | Health & social care | 2012 |
| Blackpeak Capital Ltd | Wholesale & retail | 2026 |
| Blacksea Trading Ltd | Hospitality | 2023 |
| Blackstar Finance Limited | Financial services | 2011 |
| Blackwall Reach Management Limited | Households | 1997 |
| Blackwater Bistro and Bar Limited | Hospitality | 2020 |
| Blackwater Marina Ltd | Arts & recreation | 2001 |
| Blackwell Management Company (East Grinstead) Limited | Households | 2007 |
| Blade House Limited | Households | 2012 |
| Blagrave Management Company Limited | Households | 2008 |
| Blaize Directions Limited | Administrative & support | 2012 |
| Blake Mayfair Limited | Other services | 2019 |
| Blake Smith Ltd | Administrative & support | 2022 |
| Blakelands Land Management Limited | Households | 1981 |
| Blam-Blam Ltd | Hospitality | 2013 |
| Blanc Finance Limited | Financial services | 2026 |
| Blanchetravels Ltd | Administrative & support | 2022 |
| Blanshard's Limited | Administrative & support | 2009 |
| Blaze Automation Safety Ltd | Construction | 2019 |
| Blazetiger Interactive Ltd | Wholesale & retail | 2025 |
| Bleeding Heart Radicals Limited | Information & communication | 2025 |
| Blendy Corporation LP | | 2018 |
| Blenheim Court RTM Company Limited | Hospitality | 2012 |
| Blenheim Place (Camberley) Management Company Limited | Households | 2004 |
| Blenholme Court Management (Hampton) Limited | Households | 2004 |
| Blessed Healthcare Service Ltd | Health & social care | 2022 |
| Blessed Home Rental Ltd | Real estate | 2019 |
| Blessed Journey Ltd | Wholesale & retail | 2025 |
| Blessed Vine Ltd | Wholesale & retail | 2019 |
| BLG Security Ltd | Administrative & support | 2025 |
| Bling Fish Limited | Wholesale & retail | 2024 |
| Blink Escrows Services Limited | Transport & logistics | 2025 |
| Blismart Limited | Wholesale & retail | 2024 |