| Bronzena Ltd | Manufacturing | 2022 |
| Bronzord Limited | Wholesale & retail | 2025 |
| Brook (UK) Limited | Real estate | 2006 |
| Brook Farm Training Centre Ltd | Arts & recreation | 2007 |
| Brooklyn Farm Motor Repairs Limited | Wholesale & retail | 2006 |
| Brooks Transport Services Limited | Administrative & support | 1993 |
| Broomes News & Sweets Limited | Wholesale & retail | 2025 |
| Brothers Flooring Ltd | Construction | 2021 |
| Brothers United Ltd | Construction | 2003 |
| Brothers Valet Limited | Administrative & support | 2012 |
| Brownacre Estates Ltd | Real estate | 2022 |
| Brownacre Properties Limited | Real estate | 2006 |
| Brownings Electric Company Limited | Manufacturing | 1940 |
| Browns Road Garage Limited | Wholesale & retail | 2003 |
| Bruce Landscapes Limited | Administrative & support | 2002 |
| Bruxter Ltd | Professional & scientific | 2019 |
| BS Solicitors Ltd | Professional & scientific | 2014 |
| Bsayq Ltd | Wholesale & retail | 2025 |
| Bsid Ltd | Health & social care | 2018 |
| Btrm (UK) Holdings Limited | Construction | 2023 |
| BTT Solution Ltd | Wholesale & retail | 2025 |
| Bubble and SEW Ltd | Other services | 2020 |
| Bubblebuy Ltd | Wholesale & retail | 2026 |
| Bubbles | | 1999 |
| Buch Traders Limited | Wholesale & retail | 2026 |
| Buckley Watson Limited | Professional & scientific | 2006 |
| Bucks Readymix Limited | Construction | 2022 |
| Budworth Trading Company Limited | Hospitality | 1989 |
| Bugrat Property Ltd | Real estate | 2002 |
| Build Well Homes Limited | Construction | 2004 |
| Buildfirm Establishments Limited | Construction | 2001 |
| Building Land Limited | Construction | 2014 |
| Buildmarque Limited | Other services | 1988 |
| Built Right Builders Ltd | Construction | 2025 |
| Bulgar Ltd | Transport & logistics | 2025 |
| Bull at the Gate Fleet Limited | Arts & recreation | 2024 |
| Bullbridge Estate Developments Limited | Real estate | 1962 |
| Bumble-Bee Software Limited | Information & communication | 1999 |
| Bunyamin Gunenc Limited | Wholesale & retail | 2025 |
| Burcart (Clacton) Limited | Wholesale & retail | 1984 |
| Bureau Club Limited | Extraterritorial | 2007 |
| Burney Drive(Block B)Management Company Limited | Real estate | 1984 |
| Burney Drive(Block C)Management Company Limited | Real estate | 1984 |
| Burney Drive(Block D)Management Company Limited | Real estate | 1984 |
| Burney Estates Limited | Real estate | 1997 |
| Burney Realty Limited | Construction | 1997 |
| Burnham Control Systems Ltd | Administrative & support | 2011 |
| Burnham Road Latchingdon Estate Management Company Limited | Construction | 2026 |
| Burnham Yacht Harbour Management Company Limited | Real estate | 1989 |
| Burton Bros. (London) Limited | Construction | 1987 |
| Bury ST Edmunds Ltd | Hospitality | 2013 |
| Bushby Contracts Limited | Construction | 2003 |
| Business Functions Limited | Information & communication | 2001 |
| Business Hub London Ltd | Real estate | 2012 |
| Business Intelligence & Payroll Solutions Ltd. | Professional & scientific | 2001 |
| Business Know-How Limited | Other services | 2010 |
| Business Services Limited | Extraterritorial | 2004 |
| Business Support and Mentoring Limited | Administrative & support | 2003 |
| Busylite Limited | Manufacturing | 1981 |
| Butt & Co Accountants Ltd. | Professional & scientific | 2002 |
| Butyl Products Limited | Manufacturing | 1995 |
| Buy Goodss Ltd | Wholesale & retail | 2025 |
| Buyvex Limited | Wholesale & retail | 2026 |
| Buzzville Limited | Hospitality | 2022 |
| BV Investments Limited | Real estate | 1998 |
| BY TIA B Ltd | Other services | 2024 |
| BYD Solutions Limited | Construction | 2011 |
| Byfleet (Maintenance & Electrical Contractors) Ltd | Construction | 2000 |
| Bytelink Electronics Ltd | Wholesale & retail | 2025 |
| C & a Tyres Limited | Wholesale & retail | 2006 |
| C & C Contractors (London) Limited | Construction | 1992 |
| C & C Site Services (UK) Limited | Manufacturing | 1998 |
| C & G Home Developments Ltd | Construction | 2007 |
| C & H Premier Homes Limited | Real estate | 1998 |
| C & T Properties (2016) Ltd | Real estate | 2016 |
| C and L (Leasing) Limited | Administrative & support | 1992 |
| C Crosby & Co Limited | Wholesale & retail | 2024 |
| C G Beevis Limited | Administrative & support | 2006 |
| C H Electrical Wholesalers Limited | Wholesale & retail | 1994 |
| C J Blake & Sons Limited | Construction | 2008 |
| C J`S Specialist Vehicles Ltd | Manufacturing | 2008 |
| C P Porter Fuel Merchants | | 1987 |
| C Ravensbergen Limited | Transport & logistics | 2006 |
| C S COX Limited | Construction | 2003 |
| C S Electrical Essex Limited | Construction | 2002 |
| C S World Cargo 2000 Ltd | Transport & logistics | 2000 |
| C S Wright Dental Services Limited | Health & social care | 2007 |
| C to E Global Limited | Health & social care | 2025 |
| C-Tec London Ltd | Wholesale & retail | 2018 |
| C. Blumsom Limited | Manufacturing | 1955 |
| C. Dunstan Ltd | Administrative & support | 2003 |
| C. Elect Electrical Services Limited | Construction | 2002 |
| C. K. S. Air Limited | Agriculture & fishing | 1979 |
| C.C.W. (Markets) Limited | Wholesale & retail | 1998 |
| C.D.S. (Heating + Plumbing) Limited | Construction | 1997 |
| C.E. Funston Tractor Sales Limited | Real estate | 1976 |
| C.E.Cook Developments Limited | Construction | 2001 |
| C.G Ready Ltd | Real estate | 2020 |
| C.J. Pennick (Holdings) Limited | Professional & scientific | 1995 |
| C.J.Attreed & SON Limited | | 1961 |