| Bigg Loriss Ltd | Transport & logistics | 2020 |
| Biggs Beit Management Limited | Real estate | 2023 |
| Bigupcookup Ltd | Hospitality | 2020 |
| Bigy Bags Ltd | Wholesale & retail | 2022 |
| Bihani Properties Ltd | Real estate | 2021 |
| Bikar Construction Limited | Construction | 2025 |
| Biker Wears Limited | Wholesale & retail | 2015 |
| Bilal Food Mark Limited | Information & communication | 2025 |
| Bilberry Chase (Eaton Bray) Management Limited | Households | 1989 |
| Billington & SON Contractors Limited | Construction | 2019 |
| Billys CAB Firm Ltd | Transport & logistics | 2023 |
| Billys Chicken Limited | Hospitality | 2026 |
| Bilsby Properties Ltd | Real estate | 2016 |
| Bilx Ltd | Wholesale & retail | 2026 |
| Bimla Devi Mahrra Ltd | Extraterritorial | 2022 |
| BIN Tahir Limited | Wholesale & retail | 2024 |
| Bing Property Group Ltd | Real estate | 2016 |
| Binl Ltd | Real estate | 2024 |
| Binning Wine Mart Ltd | Wholesale & retail | 2003 |
| Binx Limited | Wholesale & retail | 2018 |
| Biofoodplanet.Com Ltd | Professional & scientific | 2024 |
| Bionovax Ltd | Wholesale & retail | 2026 |
| Biopharma Services Ltd | Professional & scientific | 2025 |
| Birch Court RTM Company Limited | Households | 2023 |
| Birch CRT (Skeltons Lane) Freeholders Limited | Households | 2024 |
| Birch Financial Group Limited | Financial services | 2018 |
| Birch Grove Harpenden Management Company Limited | Households | 2016 |
| Birchfield Accommodation Ltd | Hospitality | 2021 |
| Bird Voyage Limited | Administrative & support | 2025 |
| Birds the Word Limited | Hospitality | 2022 |
| Birdsfoot Groceries Ltd | Wholesale & retail | 2026 |
| Birdsfoot Lane Food and Wine Ltd | Wholesale & retail | 2024 |
| Birdsfoot Town TUB Ltd | Other services | 2023 |
| Biriyani and Flame Limited | Hospitality | 2026 |
| Birmingham Demolition Limited | | 1986 |
| Biscot Homes Limited | Real estate | 2024 |
| Biscot Investments Ltd | Real estate | 2024 |
| Biscot Mill Food Store Ltd | Wholesale & retail | 2024 |
| Biscot Motors Ltd | Manufacturing | 2018 |
| Biscot Pharmacy Ltd | Wholesale & retail | 2014 |
| Biscot Stores Ltd | Wholesale & retail | 2010 |
| Bisdak Pinoy Lechon UK Ltd | Hospitality | 2021 |
| Bishop Industries Ltd | Administrative & support | 2018 |
| Bishops International Holdings Limited | Wholesale & retail | 2026 |
| Bisma Construction Limited | Construction | 2015 |
| Bismillah Body Shop Ltd | Wholesale & retail | 2022 |
| Bismillah Butchers Luton Ltd | Wholesale & retail | 2021 |
| Bismillah Car Hire Ltd | Administrative & support | 2023 |
| Bismillah Grocer Ltd | Hospitality | 2023 |
| Bismillah Group Hemel Limited | Hospitality | 2022 |
| Bismillah Malabar Limited | Hospitality | 2025 |
| Bismillah Traders Limited | Transport & logistics | 2018 |
| Bismillah Trading Limited | Wholesale & retail | 2025 |
| Bison Retail Ltd | Wholesale & retail | 2025 |
| Bisonte Health Care Ltd | Wholesale & retail | 2024 |
| Biss Hairdressers Ltd | Other services | 2017 |
| Bistro Food Ltd | Transport & logistics | 2024 |
| Bitivoo Limited | Wholesale & retail | 2025 |
| Bitmagic Ltd | Information & communication | 2017 |
| Bittytha Homes Limited | Administrative & support | 2024 |
| Bitum Exim Logistic Ltd | Wholesale & retail | 2021 |
| BIX & Oshin Development Ltd | Real estate | 2021 |
| BIZ Signs Ltd | Administrative & support | 2012 |
| BIZ SRS Limited | Extraterritorial | 2018 |
| BIZ Virtual Ltd | Administrative & support | 2007 |
| Bizmatic Technologies Limited | Information & communication | 2025 |
| Biznet Ltd | Wholesale & retail | 2021 |
| Bizz Travel Ltd | Transport & logistics | 2025 |
| BJL Delivery Ltd | Transport & logistics | 2023 |
| BJM Birmingham Limited | Professional & scientific | 2026 |
| BJM Contracts Ltd | Administrative & support | 2010 |
| BK Karahi Luton Ltd | Hospitality | 2026 |
| BK Lala Construction Ltd | Construction | 2024 |
| BK Legal & Compliance Ltd | Professional & scientific | 2026 |
| BK Luton Limited | Hospitality | 2025 |
| BK Space Ltd | Hospitality | 2024 |
| BKA Services Limited | Professional & scientific | 2020 |
| BKL Property Consultants LLP | | 2019 |
| Bklutontown Ltd | Hospitality | 2025 |
| Bkmg Properties Limited | Real estate | 2022 |
| BKS Luton Limited | Real estate | 2024 |
| BKY Quickfix Construction Ltd | Construction | 2024 |
| Black Dog Residential Holdings Ltd | Real estate | 2025 |
| Black Eagle Automotive Ltd | Wholesale & retail | 2024 |
| Black Folder Consulting Limited | Financial services | 2009 |
| Black Forest Carpentry Limited | Construction | 2017 |
| Black Hawk Security Services Ltd | Administrative & support | 2025 |
| Black Hill Consulting Ltd | Professional & scientific | 2012 |
| Black Horse Automotive Limited | Administrative & support | 2026 |
| Black Hunter Investment, Ltd | Extraterritorial | 2015 |
| Black Label Airport Transfers Ltd | Transport & logistics | 2024 |
| Black Label Lifestyle Ltd | Wholesale & retail | 2020 |
| Black Order Limited | Administrative & support | 2024 |
| Black Order Logistics Limited | Construction | 2024 |
| Black Pearl Cars Limited | Transport & logistics | 2017 |
| Black Pearl Logistics Ltd | Transport & logistics | 2018 |
| Black Snow Corporation Limited | Information & communication | 2025 |
| Black Swan Supplies Limited | Wholesale & retail | 2026 |
| Black Swan Transport Ltd | Transport & logistics | 2026 |
| Black Tortoise Ltd | Professional & scientific | 2024 |