| Bonster Ltd | Transport & logistics | 2016 |
| Bonta DI Sicilia Ltd | Wholesale & retail | 2025 |
| Bonviver Financial Ltd | Financial services | 2026 |
| Boobeatz Limited | Information & communication | 2025 |
| Boogi Limited | Professional & scientific | 2016 |
| Books 2 Vessels Limited | Wholesale & retail | 2009 |
| Boom Boom Room Limited | Administrative & support | 2025 |
| Boom Training Limited | Education | 2014 |
| Boom Weight Loss and Fitness Ltd | Education | 2025 |
| Boomerang Brownie Limited | Hospitality | 2023 |
| Boomerang Hamble Limited | Hospitality | 2010 |
| Boorley Carpentry & Building Ltd | Construction | 2019 |
| Booth Limited | Manufacturing | 1973 |
| Bora Living Limited | Real estate | 2021 |
| Border Town Limited | Wholesale & retail | 2021 |
| Borderland Fencing Manufacturers Limited | Manufacturing | 2022 |
| Borderland Fencing Centre Limited | Wholesale & retail | 2015 |
| Borderland Fencing Limited | Manufacturing | 1995 |
| Borderland Holdings Limited | Financial services | 2021 |
| Borderland Properties Limited | Real estate | 2021 |
| Borderlands Bakehouse LLP | | 2025 |
| Boreal Group Ltd | Financial services | 2026 |
| Borg Holdings Limited | Financial services | 2025 |
| Boroc Ltd | Wholesale & retail | 2025 |
| Borussia Digitals Sporting Academy CIC | Education | 2025 |
| Borussia Digitals Sporting Academy UK Limited | Real estate | 2025 |
| Bosinney Architects Limited | Professional & scientific | 1999 |
| Bosinney Investments Limited | Real estate | 2000 |
| Bosito Ltd | Transport & logistics | 2018 |
| Boss Spraying Limited | Construction | 2025 |
| Bossa Scaffolding Limited | Construction | 2024 |
| Bossik Ltd | Administrative & support | 2024 |
| Bossuots Metals Limited | Wholesale & retail | 2011 |
| Bosuns Chair Limited | Hospitality | 2020 |
| Bothwell Langdon Associates Limited | Professional & scientific | 1979 |
| Botley Brewery Ltd | Manufacturing | 2012 |
| Botley Brickwork Ltd | Construction | 2024 |
| Botley Car Centre Limited | Wholesale & retail | 2016 |
| Botley Motor Body Repair Limited | Wholesale & retail | 2006 |
| Botley Recruitment Services Ltd | Administrative & support | 2016 |
| Botley Renovations Ltd | Construction | 2016 |
| Botley Tree Care Ltd | Agriculture & fishing | 2022 |
| Botley Woodfired Pizza Limited | Hospitality | 2023 |
| Boujee Backdrops Ltd | Arts & recreation | 2023 |
| Boujee Productions Limited | Wholesale & retail | 2025 |
| Boule DE Suif Limited | Information & communication | 2016 |
| Boulton Composites Ltd | Construction | 2019 |
| Bouncer the Ball Ltd | Wholesale & retail | 2026 |
| Bountiful Care & Support Services Limited | Health & social care | 2017 |
| Bourke Engineering Limited | Information & communication | 2024 |
| Bournemouth Cycleworks Limited | Wholesale & retail | 2011 |
| Bournemouth Housing Assoc Ltd | Real estate | 2014 |
| Bournemouth Town Chicken Limited | Hospitality | 2017 |
| Bournemouth Tyre Centre and Service Ltd | Wholesale & retail | 2023 |
| Bourneside Consulting Limited | Professional & scientific | 2016 |
| BOW to Stern Yacht Services Ltd | Other services | 2008 |
| Bowen Engineering Limited | Professional & scientific | 2022 |
| Bowlers of London Limited | Professional & scientific | 2015 |
| Bowlers Restaurants Limited | Hospitality | 1986 |
| Bowman Accountancy Services Limited | Administrative & support | 2017 |
| Bowman Power Group Limited | Manufacturing | 2003 |
| Bowman Power Systems (UK) Limited | Extraterritorial | 2004 |
| Boxed Bridal Limited | Other services | 2023 |
| Boxyard TV Ltd | Information & communication | 2019 |
| Boyd-Fielder Ltd | Real estate | 2019 |
| Boyens Limited | Real estate | 2012 |
| Boyes Consulting Limited | Professional & scientific | 2013 |
| BPE Group Ltd | Wholesale & retail | 2024 |
| BPG (Southampton) Limited | Real estate | 2021 |
| BPG Solutions Ltd | Financial services | 2017 |
| Bpow Ltd | Real estate | 2019 |
| Bpower Energy Services Ltd | Professional & scientific | 2025 |
| BPS Design Consultants Limited | Professional & scientific | 2007 |
| Bptd Holdings Ltd | Professional & scientific | 2025 |
| Bptrm Ltd | Information & communication | 2018 |
| BR 1 Estates Limited | Hospitality | 2023 |
| BR Yachting Developments Limited | Manufacturing | 2009 |
| Bracciani Ltd | Real estate | 2023 |
| Bracken Hall Freehold Limited | Households | 2003 |
| Brackenridge Recruitment Ltd | Administrative & support | 2019 |
| Bracklyn Court RTM Company Limited | Households | 2007 |
| Bradfield Facilities Management Ltd | Households | 2014 |
| Bradfield Housing Ltd | Real estate | 2022 |
| Bradgate Business Advisors Limited | Professional & scientific | 2022 |
| Brading (Southern) Limited | Construction | 2004 |
| Bradley a Young Construction Ltd | Construction | 2019 |
| Bradleys Fish Limited | Wholesale & retail | 1996 |
| Bradrick Ltd | Wholesale & retail | 2024 |
| Braecroft Properties Ltd | Real estate | 2006 |
| Braemar RCH Limited | Health & social care | 2007 |
| Braemore Court Winchester Limited | Households | 2019 |
| Braeside Properties Limited | Real estate | 1981 |
| Braeside Property Services Limited | Construction | 2010 |
| Braeside Rentals Ltd | Households | 2025 |
| Braic Trans Ltd | Transport & logistics | 2015 |
| Brainalyze Ltd | Manufacturing | 2025 |
| Brakeley Properties Limited | Real estate | 2025 |
| Brambles Estate Agents (Warsash) Limited | Real estate | 2014 |
| Brambles Estate Agents Limited | Real estate | 2002 |
| Brambleton Construction Ltd | Construction | 2025 |