| Brownley Project Management Services Ltd | Professional & scientific | 2016 |
| Brows Academy Ltd | Other services | 2019 |
| BRS Distribution Limited | Real estate | 2018 |
| Bruce & Co (UK) Ltd | Health & social care | 2019 |
| Bruce Selby and SON Limited | Wholesale & retail | 2024 |
| Brumatrans Limited | Transport & logistics | 2023 |
| Brunel Chippenham Ltd | Hospitality | 2025 |
| Bruno & Co Investments Limited | Wholesale & retail | 2025 |
| BRUNO919 Limited | Energy | 2017 |
| BRY Healthcare Ltd | Other services | 2025 |
| Bryan and Henderson Ltd | Wholesale & retail | 2026 |
| Bryce Boarding Kennels Ltd | Other services | 2014 |
| Bryndale Strategic Ltd | Extraterritorial | 2026 |
| BS Machinery Installation Ltd | Manufacturing | 2025 |
| Bs-Traffic-Services Ltd | Public administration | 2024 |
| BSA UK Holdings Ltd | Real estate | 2024 |
| Bsbcentral Ltd | Wholesale & retail | 2025 |
| BSS Europe Ltd | Transport & logistics | 2025 |
| Bstlg Logistics Limited | Transport & logistics | 2025 |
| Btee Tribe Limited | Wholesale & retail | 2025 |
| BTT Medical Ltd | Health & social care | 2023 |
| BTZ Solutions Ltd | Transport & logistics | 2026 |
| BTZ Transport Ltd | Transport & logistics | 2025 |
| Bubble & Splash Limited | Wholesale & retail | 2009 |
| Bubble Brands Limited | Financial services | 2014 |
| Bubble MAX Ltd | Manufacturing | 2018 |
| Bubble Products Limited | Professional & scientific | 2003 |
| Bubbles for Friends Ltd. | Wholesale & retail | 2014 |
| Bubl Tea Ltd | Hospitality | 2011 |
| Bubotu Machina Ltd | Agriculture & fishing | 2021 |
| Bubs Baby UK Ltd | Wholesale & retail | 2022 |
| Bucharest Food Store Limited | Wholesale & retail | 2019 |
| Bucharest HEX Limited | Wholesale & retail | 2025 |
| Bucharest Hexthorpe Ltd | Wholesale & retail | 2022 |
| Bucharest International Limited | Wholesale & retail | 2023 |
| Bucharest Mini Market Limited | Wholesale & retail | 2026 |
| Bucket List Getaway Ltd | Administrative & support | 2023 |
| Buckley Research Ltd | Information & communication | 2023 |
| Buckley Tours Limited | Transport & logistics | 2001 |
| Bucovina Home Invest Ltd | Real estate | 2025 |
| Budlea Properties Ltd | Real estate | 2025 |
| Buff N Scuffs Ltd | Wholesale & retail | 2016 |
| Bugar Ltd | Transport & logistics | 2019 |
| Buglight Limited | Information & communication | 2016 |
| Build Damien Cain Ltd | Construction | 2025 |
| Build Right Mike Solutions Ltd | Wholesale & retail | 2026 |
| Buildgrow Limited | Real estate | 2006 |
| Building & Construction Advisor Ltd | Professional & scientific | 2025 |
| Building Group Finance Limited | Financial services | 2020 |
| Building Link Design Holdings Limited | Professional & scientific | 2010 |
| Building of Homes Limited | Construction | 2019 |
| Building Solutions (EU) Limited | Construction | 2015 |
| Buildline Procurement Ltd | Professional & scientific | 2025 |
| Buildmore Group Limited | Administrative & support | 2024 |
| Builtechnica Ltd | Other services | 2025 |
| Buja Group Limited | Real estate | 2014 |
| Bujor Services Ltd | Transport & logistics | 2025 |
| Bulkhaus Limited | Wholesale & retail | 2026 |
| Bull & Co Property Investments Limited | Real estate | 2020 |
| Bull & Lobster (York) Limited | Hospitality | 2026 |
| Bull & Lobster Holdings Limited | Real estate | 2026 |
| Bullcroft Car Care Centre Limited | Wholesale & retail | 2018 |
| Bullcroft Car Sales Limited | Wholesale & retail | 2023 |
| Bullcroft Cricket Club Limited | Hospitality | 2020 |
| Bullcroft Sports and Pastimes Club Limited | Hospitality | 2005 |
| Bullet Kandy Ltd | Wholesale & retail | 2024 |
| Bullion Club Ltd | Wholesale & retail | 2020 |
| Bullseye Superfactors EOT Limited | Financial services | 2024 |
| Bullseye Superfactors Holdings Limited | Wholesale & retail | 2018 |
| Bullseye Superfactors Ltd | Wholesale & retail | 1995 |
| Buma Limited | Professional & scientific | 2012 |
| Bumble & Beam Limited | Extraterritorial | 2026 |
| BUN & Base Ltd | Hospitality | 2020 |
| Bunk Hotels Ltd | Hospitality | 2014 |
| Burger JIM Pizza Limited | Hospitality | 2023 |
| Burger Pizza Ltd | Hospitality | 2026 |
| Burger Restaurant Limited | Hospitality | 2026 |
| Burgess Limited | Administrative & support | 2020 |
| Burhouse Construction Limited | Construction | 2021 |
| Burlan Protap Ltd | Transport & logistics | 2021 |
| Burlington Property Investments Ltd | Real estate | 2019 |
| Burnett Mortgages Limited | Financial services | 2018 |
| Burnham Manor Limited | Construction | 2026 |
| Burns Cottages Ltd | Real estate | 2020 |
| Burns Horticulture Ltd | Administrative & support | 2023 |
| Burntwood Canine Hydrotherapy Limited | Professional & scientific | 2023 |
| Burrad LOG Limited | Transport & logistics | 2022 |
| Burrell Construction Holdings Ltd | Financial services | 2023 |
| Burrows Portfolio Ltd | Real estate | 2025 |
| Burton & Family Holdings Limited | Construction | 2020 |
| Burton Howard Holdings Ltd | Real estate | 2017 |
| Burton Howard Investments Limited | Real estate | 2017 |
| Bury & Co Firm Ltd | Information & communication | 2025 |
| BUSIEREASIER2222 Ltd | Wholesale & retail | 2025 |
| Business Efficiency Experts Ltd | Administrative & support | 2025 |
| Business Funding and Finance Lender Limited | Other services | 2016 |
| Business Funding and Finance Limited | Other services | 2016 |
| Business Language Whisper Ltd | Administrative & support | 2024 |
| Business Operating Model Design Solutions Ltd | Wholesale & retail | 2022 |
| Business Services Your Way Limited | Other services | 2013 |