| Bolt Aerospace Ltd | Manufacturing | 2025 |
| Bolt Global Ltd | Wholesale & retail | 2024 |
| BOLT6 Limited | Administrative & support | 2021 |
| Bona Limited | Wholesale & retail | 1999 |
| Bonakemi Limited | Extraterritorial | 2009 |
| Bonakemi UK Limited | Extraterritorial | 1999 |
| Bonbon Boom Ltd | Hospitality | 2026 |
| Boncom Ltd. | Wholesale & retail | 2025 |
| Bond and Hope Ltd | Construction | 2022 |
| Bond London Limited | Real estate | 2012 |
| Bond Vehicle Leasing Ltd | Administrative & support | 2015 |
| Bondnow Limited | Information & communication | 2025 |
| Bong UK Limited | Manufacturing | 1999 |
| Boniface Properties Ltd | Real estate | 2025 |
| Bonn Consulting Ltd | Professional & scientific | 2016 |
| Bonneyhill Limited | Households | 1994 |
| Bonobo Legal Limited | Information & communication | 2023 |
| Bont Construction Limited | Construction | 2025 |
| Bonus Brazil Limited | Extraterritorial | 2019 |
| Bonventure Service Limited | Health & social care | 2012 |
| Bonyika Limited | Transport & logistics | 2015 |
| Boo's Aesthetics and Beauty Ltd | Other services | 2025 |
| Boob Buddy Ltd | Manufacturing | 2019 |
| Boodle Designer Clothing Ltd | Other services | 2017 |
| Boodle Estates Ltd | Real estate | 2016 |
| Boogie Masters Limited | Wholesale & retail | 2024 |
| Bookeet Limited | Information & communication | 2023 |
| Bookhire Limited | Extraterritorial | 1999 |
| Bookitease Ltd | Administrative & support | 2026 |
| Booklores Ltd | Professional & scientific | 2018 |
| Bookr Apps Ltd | Information & communication | 2026 |
| Boom Seven Ltd | Professional & scientific | 2022 |
| Booming Games (UK) Limited | Other services | 2015 |
| Boosst Financial Limited | Financial services | 2017 |
| Boosst Your Legacy Limited | Professional & scientific | 2019 |
| Boost Drinks Limited | Wholesale & retail | 2001 |
| Boot Camp Brands Limited | Wholesale & retail | 2011 |
| Booze Boys Ltd | Wholesale & retail | 2025 |
| Boredom Inc. Ltd | Professional & scientific | 2025 |
| Boring Balloon Limited | Wholesale & retail | 2020 |
| Boring Butler Ltd | Information & communication | 2025 |
| Borivali Consultancy Limited | Information & communication | 2017 |
| BORN2BE Academy Ltd | Professional & scientific | 2026 |
| Boruz Partnership Ltd. | Professional & scientific | 2013 |
| Bosaik Limited | Health & social care | 2018 |
| Bosi Consultancy Ltd | Hospitality | 2015 |
| Bosi Pubs Limited | Hospitality | 2013 |
| Boslan Ltd | Professional & scientific | 2023 |
| Bosnian Kebab Ltd | Hospitality | 2025 |
| Boss Distribution Ltd | Wholesale & retail | 2024 |
| Boss London Ltd | Wholesale & retail | 2018 |
| Boss XR Motors Limited | Wholesale & retail | 2026 |
| Bossjojo Limited | Health & social care | 2017 |
| Bosson-Hill Properties Limited | Real estate | 2025 |
| Bosstech Digital Ltd | Information & communication | 2024 |
| Bosstech Retail South Ltd | Wholesale & retail | 2020 |
| Boston Design Consultants Limited | Manufacturing | 2006 |
| Bostons W/S Ltd | Other services | 2026 |
| Bosun Music & PA Ltd | Information & communication | 2024 |
| Bosworth Smith Limited | Construction | 2021 |
| Bothe Technical Services Limited | Transport & logistics | 2010 |
| Botolph Green Developments Limited | Real estate | 2011 |
| Botolph Green Investments Limited | Administrative & support | 2013 |
| Bottled Holdings Ltd | Education | 2015 |
| Boughton Group Limited | Professional & scientific | 2016 |
| Boughton Property Developments Limited | Real estate | 2018 |
| Boultbee Corinthian Property Company Limited | Real estate | 1988 |
| Bounders Ltd | Wholesale & retail | 2019 |
| Bourne Bridge Investments Limited | Real estate | 2021 |
| Boutique Holdings Limited | Professional & scientific | 2025 |
| BOW Brickhill Road Flats Management Company Limited | Households | 2001 |
| BOW Properties Ltd | Households | 2023 |
| Bowcott Family Investments Ltd | Real estate | 2023 |
| Bowdler Contractors Limited | Construction | 1998 |
| Bowed Creative Limited | Professional & scientific | 2017 |
| Bowen Nicholas Ltd | Administrative & support | 2017 |
| Bowens of Boston Limited | Real estate | 2016 |
| Bowers Contracting Ltd | Construction | 2024 |
| Bowhole Ltd | Professional & scientific | 2025 |
| Bowick Enterprises Limited | Hospitality | 2017 |
| Bowling Avenue Luxury Homes Limited | Real estate | 2019 |
| Box Clever UK Limited | Administrative & support | 1990 |
| Box Consultants Limited | Administrative & support | 2015 |
| Box Fit Centre Ltd | Education | 2025 |
| Box ME a Rice Holdings Ltd | Hospitality | 2025 |
| Box ME a Rice Ltd | Health & social care | 2013 |
| Box of Toys Consulting Ltd | Information & communication | 2010 |
| BOX74 Limited | Professional & scientific | 2008 |
| Boxing Lounge Ltd | Arts & recreation | 2024 |
| Boxinvest Ltd | Real estate | 2023 |
| Boxmaker.Pro Ltd | Wholesale & retail | 2024 |
| Boyd Maritime Consultants Limited | Professional & scientific | 2025 |
| Boyle Highways Limited | Other services | 2014 |
| Boymer Sacca Ltd | Wholesale & retail | 2020 |
| Bozzcurt Homes Ltd | Construction | 2023 |
| Bozzmoss Cleans Ltd | Administrative & support | 2025 |
| BP Polishing Limited | Wholesale & retail | 2021 |
| Bp&P Ltd | Wholesale & retail | 2022 |
| BPB Electrical Limited | Construction | 2016 |
| BPB Group Limited | Financial services | 2024 |