| Biosens Limited | Professional & scientific | 2019 |
| Biotat Limited | Administrative & support | 2022 |
| Biotic Media Limited | Information & communication | 2017 |
| Biow UK Limited | Construction | 2021 |
| Birch Education Ltd | Education | 2020 |
| Birch Service Centre Limited | Wholesale & retail | 2020 |
| Bird Contracting Ltd | Information & communication | 2015 |
| Birdie Investments Limited | Financial services | 2023 |
| Birdys Logistics Limited | Transport & logistics | 2021 |
| Birkdale Allen ST Ltd | Real estate | 2021 |
| Birkdale Court Residents Management Company Limited | Real estate | 2003 |
| Birkdale Design Limited | Professional & scientific | 2008 |
| Birkdale Property Investments Limited | Real estate | 2013 |
| Birkdale Traders Ltd | Wholesale & retail | 2023 |
| Birsa Ltd | Wholesale & retail | 2023 |
| Birtenshaw | Education | 1994 |
| Birtenshaw Construction Limited | Construction | 2019 |
| Birtenshaw Merseyside | Education | 2016 |
| Biryani Bazaar Ltd | Wholesale & retail | 2025 |
| Bisgin & Partners Limited | Information & communication | 2018 |
| Bishop Electrical Services Ltd | Construction | 2023 |
| Bishops Rock Consulting Ltd | Professional & scientific | 2013 |
| Bishops Rock Properties Limited | Construction | 1999 |
| Bishopsrock Holdings Limited | Financial services | 2025 |
| Bishopsrock Investment Holdings Limited | Financial services | 2025 |
| Bishukrihi Ltd | Hospitality | 2020 |
| Bisidom Ltd | Professional & scientific | 2018 |
| Bism Generale UK Ltd | Construction | 2026 |
| Bisma Building Supplies Limited | Wholesale & retail | 2025 |
| Bismil Auto Limited | Wholesale & retail | 2025 |
| Bismillah Auto Group Limited | Wholesale & retail | 2026 |
| Bismillah Corporation Ltd | Wholesale & retail | 2026 |
| Bistro Bombay Ltd | Financial services | 2025 |
| Bitabobs Limited | Arts & recreation | 2016 |
| Bite N Joy Ltd | Hospitality | 2026 |
| Bitecrunch Limited | Information & communication | 2014 |
| Bitegen Ltd | Wholesale & retail | 2024 |
| Bites N' Delights Limited | Hospitality | 2025 |
| Bithells Limited | Extraterritorial | 2009 |
| Bitmoat Limited | Information & communication | 2019 |
| Bits & Bytes IT Consultancy Limited | Information & communication | 2023 |
| Bits, Bytes & Beyond Limited | Information & communication | 2026 |
| Bitverve Services Ltd | Information & communication | 2026 |
| Biyrite Hardware Ltd | Wholesale & retail | 2025 |
| BIZ Audit Ltd | Administrative & support | 2023 |
| BIZ Trade UK Limited | Wholesale & retail | 2018 |
| Bizfast Services Ltd | Transport & logistics | 2025 |
| Bizka Beauty Limited | Wholesale & retail | 2023 |
| Biztax Consultancy Ltd | Professional & scientific | 2025 |
| Biztonext Ltd | Information & communication | 2025 |
| Bizzapps Consulting Ltd | Information & communication | 2020 |
| Bizzapps Property Holdings Ltd | Real estate | 2024 |
| BJ Accounting Solutions Ltd | Professional & scientific | 2025 |
| BJC Care Limited | Financial services | 2020 |
| BJH Estates Limited | Real estate | 2021 |
| BJK Pharma Consulting Ltd | Professional & scientific | 2019 |
| BJK Plumbing & Heating Services Ltd | Construction | 2023 |
| BJM Landscape Ltd | Administrative & support | 2023 |
| BJP Media Enterprises Limited | Information & communication | 2024 |
| BJW Property (Bolton) Ltd | Real estate | 2011 |
| BJW Stores (Bolton) Ltd | Wholesale & retail | 2018 |
| BJZ Group Ltd | Water & waste | 2020 |
| BK Chops Limited | Hospitality | 2025 |
| BK Door Installations Limited | Construction | 2014 |
| BK Property Investments Ltd | Real estate | 2021 |
| BK Tyres & Exhausts Ltd | Wholesale & retail | 2024 |
| Bkam Solutions Ltd | Wholesale & retail | 2026 |
| BKE Limited | Transport & logistics | 2026 |
| Bkfc Europe Limited | Professional & scientific | 2024 |
| Bkind Cleaning Services Limited | Administrative & support | 2026 |
| Bkjl Limited | Information & communication | 2020 |
| BKO Properties Ltd | Real estate | 2024 |
| BKP Associates Ltd | Health & social care | 2022 |
| Bksj Limited | Financial services | 2009 |
| Bksons Ltd | Construction | 2024 |
| BKW Foodstores Ltd | Administrative & support | 2017 |
| BL Airconditioning Ltd | Construction | 2023 |
| BL Lettings Limited | Real estate | 2025 |
| BL Motors Ltd | Wholesale & retail | 2025 |
| BL2 Local Ltd | Manufacturing | 2026 |
| BL4 Live Ltd | Arts & recreation | 2019 |
| BL6 Ltd | Real estate | 2022 |
| Black Box Contracts Limited | Construction | 2024 |
| Black Bull Tavern (Catering) Ltd | Hospitality | 2026 |
| Black Bull Tavern Ltd | Hospitality | 2025 |
| Black Diamond Bars Ltd | Hospitality | 2018 |
| Black Dog Scaffolding Ltd | Construction | 2025 |
| Black Lotus Designs Ltd | Professional & scientific | 2013 |
| Black Props Ltd | Real estate | 2025 |
| Black Rock Supplements Ltd | Wholesale & retail | 2024 |
| Black Rock Vets Ltd | Professional & scientific | 2016 |
| Black Sea Academy Ltd | Education | 2025 |
| Black Sea Brokers Limited | Extraterritorial | 2019 |
| Black Sheep Business Communications Ltd | Information & communication | 2006 |
| Black Stallion Cars Limited | Wholesale & retail | 2020 |
| Black Stone Support Ltd | Professional & scientific | 2024 |
| Black Toucan Ltd | Information & communication | 2018 |
| Black United Representation Network CIC | Professional & scientific | 2020 |
| Black Wire Civil Engineering Limited | Professional & scientific | 2011 |
| Black Wire Plant Hire Limited | Administrative & support | 2014 |