| Bistro S&M Ltd | Hospitality | 2024 |
| BIT Famous Limited | Information & communication | 2019 |
| Bitcanvas Ltd | Information & communication | 2025 |
| Bitdisplay Ltd | Professional & scientific | 2021 |
| Bite ME Snacks Ltd | Manufacturing | 2025 |
| Bite Time Limited | Hospitality | 2022 |
| Biteback Media Ltd | Information & communication | 2018 |
| Biters Enterprises Ltd | Hospitality | 2023 |
| Bitkin Limited | Information & communication | 2025 |
| Bitmead Property Investments Limited | Real estate | 2022 |
| Bitnova Ltd | Information & communication | 2025 |
| Bits Spectrum Global Ltd | Information & communication | 2021 |
| Bitstream Tech Ltd | Information & communication | 2021 |
| Bittelgrove Limited | Professional & scientific | 1978 |
| Biuvio 31 Ltd | Administrative & support | 2017 |
| BIZ Accounting Ltd | Professional & scientific | 2010 |
| BIZ Advisors Ltd | Extraterritorial | 2016 |
| BIZ E-Commerce PVT Limited | Information & communication | 2022 |
| BIZ Law Limited | Professional & scientific | 2011 |
| BIZ Place Ltd | Real estate | 2013 |
| BIZ Properties Limited | Households | 2023 |
| Bizsheet Ltd | Extraterritorial | 2015 |
| Biztech Trading Limited | Wholesale & retail | 2023 |
| Biztrain Solutions Limited | Education | 2015 |
| Bizvista Solutions Limited | Professional & scientific | 2025 |
| BJ Group Property Limited | Construction | 2015 |
| BJM Benefits Limited | Administrative & support | 2024 |
| BJM Employment Ltd | Professional & scientific | 2025 |
| BJM Salary Limited | Professional & scientific | 2025 |
| Bjorn Limited | Other services | 2004 |
| BJP Kitchen Ltd | Hospitality | 2025 |
| Bjpm Limited | Wholesale & retail | 2026 |
| BJR Electrical Limited | Construction | 2016 |
| BJS 7 Limited | Professional & scientific | 2020 |
| BJS Gardens Ltd | Administrative & support | 2026 |
| BK Global Relocations Ltd | Hospitality | 2023 |
| BK Rutland Properties Limited | Real estate | 2022 |
| BK40 Ltd | Other services | 2004 |
| BKA Design Ltd | Professional & scientific | 2020 |
| BKB Consulting Services Limited | Professional & scientific | 2020 |
| BKB Group Limited | Real estate | 2024 |
| BKG Homes Limited | Real estate | 2021 |
| Bkls Properties Ltd | Real estate | 2017 |
| BKP International Ltd | Wholesale & retail | 2023 |
| BKR Business Consultancy Ltd | Professional & scientific | 2024 |
| BKY London Ltd | Real estate | 2016 |
| Black and Yellows Construction Ltd | Construction | 2014 |
| Black Bay Property Ltd | Real estate | 2021 |
| Black Biitz Ltd | Extraterritorial | 2020 |
| Black Box Insights Limited | Information & communication | 2024 |
| Black Box Strategy Ltd | Professional & scientific | 2021 |
| Black Cat Associates (London) Limited | Financial services | 2019 |
| Black Cat Associates Limited | Financial services | 2023 |
| Black Diamond Construction Ltd | Construction | 2024 |
| Black Diamonds Family Ltd | Professional & scientific | 2024 |
| Black Dog SPV Limited | Information & communication | 2021 |
| Black Eagle Sailing Ltd | Extraterritorial | 2023 |
| Black Edge Productions Ltd | Professional & scientific | 2016 |
| Black Glasses Limited | Wholesale & retail | 2016 |
| Black Jack's Mill Ltd. | Real estate | 2007 |
| Black Lotus Yoga Ltd | Education | 2024 |
| Black Sea Fish Ltd | Other services | 2018 |
| Black Steel Installation Ltd | Construction | 2023 |
| Black Tiger Global Limited | Other services | 2010 |
| Black Tulip Retail Ltd | Manufacturing | 2023 |
| Black Volcano Limited | Financial services | 2017 |
| Black Wedge Limited | Information & communication | 2024 |
| Blackbird TMT Limited | Financial services | 2013 |
| Blackborough House Limited | Construction | 2015 |
| Blackbox Holdings Limited | Financial services | 2019 |
| BLACKEAGLE1903 Ltd | Real estate | 2024 |
| Blackgem Limited | Professional & scientific | 2010 |
| Blacks Business Consultancy Management Ltd | Administrative & support | 2020 |
| Blacks Real Estate Ltd | Real estate | 2018 |
| Blackscorp Ltd | Construction | 2016 |
| Blacksmith (UK) Limited | Wholesale & retail | 2009 |
| Blacksmiths Palace Ltd | Agriculture & fishing | 2020 |
| Blackstar Property Management Ltd | Households | 2020 |
| Blackstone Building Solutions Ltd | Construction | 2023 |
| Blackstone Claims Ltd | Administrative & support | 2016 |
| Blackstone Consulting Services Limited | Information & communication | 2016 |
| Blackstone House Limited | Information & communication | 2011 |
| Blackstone House Publications Ltd | Information & communication | 2011 |
| Blackstone Law Associates Ltd | Professional & scientific | 2009 |
| Blackstone Roofing Ltd | Construction | 2024 |
| Blacksuit Learnings Ltd | Education | 2022 |
| Blacksword Capital Limited | Professional & scientific | 2023 |
| Blackwater Estates Limited | Construction | 2002 |
| Blackwater Residential Ltd | Real estate | 2022 |
| Blackwax Ltd | Other services | 2018 |
| BLACKWING7 Limited | Professional & scientific | 2019 |
| Blakes Homes Limited | Construction | 2003 |
| Blame Ltd | Wholesale & retail | 2025 |
| Blanco Consulting Ltd | Construction | 2015 |
| Blankpage 1 GP LLP | | 2025 |
| Blankpage 1 LP | | 2025 |
| Blankpage Capital Ltd | Professional & scientific | 2024 |
| Blart Incorporation Limited | Wholesale & retail | 2025 |
| Blawith Road Freehold Company Limited | Real estate | 2012 |
| Blaydon Wealth Management Limited | Financial services | 2026 |