| Britten Electrical Services Ltd | Construction | 2020 |
| BRKT3 Fish Limited | Hospitality | 2024 |
| Broad Target Tech Services Ltd | Information & communication | 2024 |
| Broadgreen Living Ltd | Real estate | 2026 |
| Broadland Construction Limited | Construction | 1992 |
| Broadstone Consultants Ltd | Professional & scientific | 2014 |
| Broadway Chambers Estates Limited | Real estate | 2014 |
| Broken Healthcare and Wellbeing Ltd | Health & social care | 2026 |
| Bromley Brickwork Limited | Construction | 2018 |
| Brooke Installation Limited | Construction | 2003 |
| Brooke Tucker Management Limited | Professional & scientific | 2023 |
| Brooke-Ventilation Limited | Manufacturing | 2017 |
| Broomhill Windows and Doors Ltd | Construction | 2026 |
| Broomway Limited | Financial services | 2001 |
| Brothers Fish Bar and Grill Ltd | Hospitality | 2023 |
| Brothers Performance Ltd | Wholesale & retail | 2017 |
| Brown Europe Limited | Manufacturing | 1990 |
| Brown's Property Solutions Ltd | Real estate | 2017 |
| Brun Limited | Arts & recreation | 2006 |
| Brunos Builders and Construction Ltd | Construction | 2025 |
| Brux Fashion Ltd | Wholesale & retail | 2017 |
| Brygate Ltd | Professional & scientific | 2020 |
| BS Cleaning Services Ltd | Administrative & support | 2019 |
| BS Metalwork & Construction Services Ltd | Construction | 2022 |
| BSB (Medway) Limited | Real estate | 2003 |
| BSC 1 Limited | Transport & logistics | 2025 |
| Bskeh Homes Ltd | Real estate | 2022 |
| BSL Properties Limited | Real estate | 2004 |
| Bssh Contracting Limited | Construction | 2019 |
| BT Cleaning Services Limited | Administrative & support | 2020 |
| BTD Electrical Limited | Administrative & support | 2005 |
| BTE Property Solution Ltd | Real estate | 2022 |
| Bu-Corp Ltd | Health & social care | 2021 |
| Bu-Mentoring "UK" C.I.C. | Education | 2013 |
| Bubbleo Tree Ltd | Hospitality | 2022 |
| Bubbles Style Ltd | Wholesale & retail | 2020 |
| Buca Ltd | Information & communication | 2010 |
| Buckland Firearms Ltd | Wholesale & retail | 2022 |
| Buckmore Park Forest School Ltd | Education | 2019 |
| Buckmore Park Holdings Limited | Financial services | 2019 |
| Buckmore Park Karting Limited | Arts & recreation | 2015 |
| Bucknall Landscape Services Limited | Administrative & support | 2001 |
| Budnik Ltd | Construction | 2022 |
| Buffalo Accountants Ltd | Professional & scientific | 2026 |
| Bufford Consulting Ltd | Professional & scientific | 2023 |
| Bufftail Ltd | Information & communication | 2019 |
| Buildabuggy Ltd | Wholesale & retail | 2023 |
| Builddemand Limited | Construction | 2019 |
| Building M8 Ltd | Construction | 2023 |
| Building Nests Ltd | Construction | 2024 |
| Buildiq Systems Ltd | Professional & scientific | 2025 |
| Buildsmart Supply Co Limited | Wholesale & retail | 2024 |
| Bukso Ltd | Administrative & support | 2024 |
| Bul-Pol Ltd | Transport & logistics | 2015 |
| Bull Ferguson Limited | Financial services | 2009 |
| Bullscaff Limited | Agriculture & fishing | 2019 |
| Bumade Healthcare Services Ltd | Health & social care | 2021 |
| BUP Arts CIC | Arts & recreation | 2023 |
| Burham Island Limited | Real estate | 2025 |
| Burklan Ltd | Manufacturing | 2020 |
| Burlanes Limited | Manufacturing | 2019 |
| Burly Group Limited | Administrative & support | 2021 |
| Burnham-Leeds Traders Ltd | Wholesale & retail | 2025 |
| Burraq Chauffeur Drive Ltd | Wholesale & retail | 2011 |
| Burton P M Limited | Construction | 2017 |
| Burtons Law Costs Draftsman Services Limited | Professional & scientific | 2026 |
| Burwood Conversions Ltd | Construction | 2017 |
| Busad Enterprises Ltd | Wholesale & retail | 2024 |
| Bushkraft Forest School CIC | Hospitality | 2019 |
| Bushrod PUB Co Ltd | Hospitality | 2019 |
| Business Continuity Solutions Limited | Professional & scientific | 2012 |
| Business Information Excellence Limited | Information & communication | 2016 |
| Business Solutionz Ltd | Administrative & support | 2025 |
| Businesslight Relocations & Property Servicing Ltd | Real estate | 2021 |
| Butler Marine Limited | Administrative & support | 2007 |
| Butterfly Consulting Limited | Professional & scientific | 2025 |
| Buy Clearance Ltd | Wholesale & retail | 2025 |
| Buy&Sales Motors UK Ltd | Wholesale & retail | 2021 |
| Buybrand Limited | Financial services | 2014 |
| Buying & Selling Online Ltd | Wholesale & retail | 2022 |
| Buzz SR Limited | Professional & scientific | 2019 |
| BW Carpentry & Construction Ltd | Construction | 2024 |
| Bw.Property&Investments Ltd | Real estate | 2024 |
| Bycasp Ltd | Professional & scientific | 2024 |
| BYLL67 Ltd | Transport & logistics | 2019 |
| Byrne Contractors Limited | Construction | 1986 |
| Byrne Developments Ltd | Extraterritorial | 2021 |
| C & a Properties (Kent) Limited | Professional & scientific | 2014 |
| C & BR Enterprises Limited | Real estate | 2021 |
| C & C Tax Factory Ltd | Professional & scientific | 2023 |
| C & D Property Services Ltd | Real estate | 2026 |
| C & L Properties (Kent) Limited | Real estate | 2025 |
| C & N Glazing Limited | Construction | 2023 |
| C & Q Services Ltd | Construction | 2018 |
| C & R Builders South East Ltd | Construction | 2015 |
| C & S Plant Hire Limited | Construction | 2003 |
| C & W Groundcare Limited | Administrative & support | 2008 |
| C a M Vaccaro Consultancy Limited | Administrative & support | 2007 |
| C Davidson Consultancy Ltd | Information & communication | 2019 |
| C G Construction (South East) Limited | Construction | 2015 |