| Binks (Holdings) Limited | Real estate | 2014 |
| Binks Vertical Limited | Construction | 2003 |
| Biostress LAB Ltd | Administrative & support | 2020 |
| Bird and Batter Ltd | Hospitality | 2025 |
| Birkwood House Farm (Storage) Ltd | Transport & logistics | 2010 |
| Birkwood Plant Training Ltd. | Education | 2007 |
| Birkwood Transport Services Limited | Transport & logistics | 2018 |
| Bison Carpentry Ltd | Construction | 2018 |
| Bison Fabrications Ltd | Manufacturing | 2013 |
| Bixby Higdon LP | | 2015 |
| Bizzloc Ltd. | Information & communication | 2013 |
| BJD Crushers Limited | Manufacturing | 2001 |
| BJD Processing Limited | Extraterritorial | 2024 |
| BJM Civils Ltd | Professional & scientific | 2022 |
| BL NO. 2 Limited | Real estate | 2015 |
| Black Asset Ltd | Professional & scientific | 2018 |
| Black Byte Ltd | Wholesale & retail | 2025 |
| Black Diamond Trucking Company (London) Ltd | Professional & scientific | 2011 |
| Black Farm Butchers Limited | Hospitality | 2024 |
| Black Finch Developments Ltd | Real estate | 2020 |
| Black Hole Films Ltd | Arts & recreation | 2021 |
| Black Horse (Westgate) Ltd | Hospitality | 2020 |
| Black Horse Thornhill Ltd | Hospitality | 2025 |
| Black Watch Documentaries Limited | Extraterritorial | 2003 |
| Blackbird Innovation Group Ltd | Financial services | 2021 |
| Blacker Hall Farm Shop Limited | Wholesale & retail | 2005 |
| Blackgates Management Company (WKD) Limited | Households | 2015 |
| Blackheart Estates Limited | Real estate | 2025 |
| Blacklight Software Limited | Information & communication | 2009 |
| Blacon EYE Care Ltd | Health & social care | 2016 |
| Blades Hair Systems Limited | Other services | 2018 |
| Blades Ramble Ltd | Manufacturing | 2023 |
| Blakeridge Holdings 1 Limited | Real estate | 2017 |
| Blakeridge Holdings 2 Limited | Real estate | 2017 |
| Blakeridge Mill Management Company Limited | Real estate | 2008 |
| Blanc Property Finance Limited | Financial services | 2021 |
| Blanks Property Ltd | Construction | 2025 |
| BLB (UK) Limited | Professional & scientific | 2012 |
| BLB Accounting Limited | Professional & scientific | 2024 |
| Blenheim Square Limited | Real estate | 2023 |
| Blessed Hands Healthcare Limited | Health & social care | 2018 |
| Blimation Limited | Arts & recreation | 2019 |
| Blind Alley Ltd | Manufacturing | 2010 |
| Blinds Master Ltd | Wholesale & retail | 2022 |
| Bliss BEE Ltd | Health & social care | 2026 |
| Blissful Home Living Ltd | Wholesale & retail | 2020 |
| Blithely Limited | Wholesale & retail | 2024 |
| Block Buddie Limited | Wholesale & retail | 2023 |
| BLU Chip Compliance Ltd | Professional & scientific | 2025 |
| Blue Bear Inc. Ltd | Wholesale & retail | 2024 |
| Blue Diamond Training Limited | Education | 2016 |
| Blue Light Fire and Security Limited | Administrative & support | 2019 |
| Blue Marlin on Wheels Limited | Hospitality | 2026 |
| Blue Mist Local Limited | Wholesale & retail | 2025 |
| Blue Pyrus Ltd | Administrative & support | 2022 |
| Blue Rock E-Commerce Ltd | Wholesale & retail | 2023 |
| Blue Sky Design School Limited | Education | 2025 |
| Blue Sky Resorts Limited | Hospitality | 2004 |
| Bluebell (Southern) Ltd | Health & social care | 2016 |
| Bluehorse Finance Limited | Financial services | 2006 |
| Bluehorse LDN Ltd | Wholesale & retail | 2022 |
| Bluescan Limited | Professional & scientific | 2025 |
| Bluestone Capital Limited | Financial services | 2007 |
| Bluestone Finance Limited | Financial services | 2006 |
| Bluestone Leasing Limited | Financial services | 1990 |
| Bluestone Trustee Limited | Professional & scientific | 2017 |
| Bmah Ltd | Administrative & support | 2024 |
| Bmma Leeds Ltd | Arts & recreation | 2021 |
| BMS Locums Ltd | Health & social care | 2021 |
| BNA Property Limited | Real estate | 2014 |
| BNC Promotions Limited | Professional & scientific | 2021 |
| BNJ Bars Limited | Hospitality | 2018 |
| Boar Home Dining Ltd | Hospitality | 2021 |
| Boardman Pitts Associates Limited | Professional & scientific | 1993 |
| Boardman Wealth Management Ltd | Financial services | 1999 |
| BOARDS-4U Limited | Manufacturing | 2022 |
| Boateng Elite Cleaning Service Ltd | Administrative & support | 2026 |
| Bod-Naut Limited | Manufacturing | 2018 |
| Boda-Protech Limited | Administrative & support | 2007 |
| Bodyfokus Ltd | Extraterritorial | 2016 |
| Boiler Room Project Ltd | Arts & recreation | 2026 |
| Bokitchen Ltd | Hospitality | 2023 |
| Bold Kitchens Limited | Manufacturing | 2018 |
| Bombay Warrington Ltd | Hospitality | 2023 |
| Bonjourdeals Ltd | Wholesale & retail | 2025 |
| Boom Hub Limited | Wholesale & retail | 2022 |
| Booth Energy Management Systems (Bems) Limited | Construction | 2017 |
| Bootroom New Media Ltd | Information & communication | 2017 |
| Boparan Finance PLC | Professional & scientific | 2011 |
| Boparan Foods Limited | Manufacturing | 1996 |
| Boparan Holdings Limited | Professional & scientific | 1998 |
| Boparan Service Group Limited | Administrative & support | 2025 |
| Boreal Developments Ltd. | Real estate | 2024 |
| Boreal Finds Ltd | Real estate | 2025 |
| Boreal Lets Ltd | Hospitality | 2026 |
| Bosoi Limited | Transport & logistics | 2019 |
| Bosquet VIE Limited | Wholesale & retail | 1993 |
| Boths Services Ltd | Information & communication | 2026 |
| Boulton Property Freehold Limited | Professional & scientific | 2006 |
| Boulton Property Investment Limited | Real estate | 2006 |