| Berkshire Car Hire Limited | Transport & logistics | 2018 |
| Berkshire Metals Limited | Wholesale & retail | 2002 |
| Berryrich Limited | Professional & scientific | 2022 |
| Best Trading (GB) Limited | Wholesale & retail | 2005 |
| Bewal Foods Limited | Hospitality | 2007 |
| BGO Services Ltd | Construction | 2007 |
| Bharati Patel Ltd | Professional & scientific | 2003 |
| BIN Garden Ltd | Manufacturing | 2001 |
| Binary Accounting Services Ltd | Professional & scientific | 2024 |
| Binderway Limited | Real estate | 1981 |
| Biohybrids International Limited | Agriculture & fishing | 1996 |
| Birch Commercial Furnishings Limited | Wholesale & retail | 2006 |
| Birch Parade Management Company Limited | Households | 1990 |
| Bitbash Ltd | Information & communication | 2002 |
| BKB Property Limited | Real estate | 2019 |
| Black Tusk Consulting Ltd | Professional & scientific | 2021 |
| Blackrock Pictures Limited | Information & communication | 2016 |
| Blair Impex Limited | Other services | 1988 |
| Blandys Limited | Professional & scientific | 2007 |
| Blind Maggot Ltd | Wholesale & retail | 2020 |
| Blue Anchor Limited | Real estate | 1999 |
| Blue Surf Consulting Limited | Professional & scientific | 2000 |
| BMC Helix UK Limited | Information & communication | 2025 |
| BML Solutions Limited | Information & communication | 2005 |
| BOA Engineering Limited | Manufacturing | 2007 |
| Boehringer Ingelheim Limited | Manufacturing | 1962 |
| Bondcircle Limited | | 1984 |
| Border Personnel Limited | Professional & scientific | 1989 |
| Born to Move Ltd | Health & social care | 2006 |
| Borovere Development Limited | Construction | 1983 |
| Botanica Nurseries Ltd | Agriculture & fishing | 2007 |
| Bourne Labs Limited | Information & communication | 2004 |
| Boys-R-Us Limited | Extraterritorial | 2004 |
| Bradshaw Services (Cleaning) Limited | Professional & scientific | 1984 |
| Brand Windows Limited | Manufacturing | 1973 |
| Brandwarehouse.Co.Uk Limited | Extraterritorial | 1972 |
| Bravic Properties Limited | Real estate | 1983 |
| Bray Business Centre | | 1993 |
| Braywick Heath Nurseries Ltd | Administrative & support | 1996 |
| Brenbell Property Management Limited | Households | 1997 |
| Brennan Transport Limited | Transport & logistics | 2003 |
| Brewin Carolan & Sons Limited | Construction | 2005 |
| Bridge Consultancy (UK) Limited | Professional & scientific | 2003 |
| Brightcall Limited | Other services | 2002 |
| Brightside UK Limited | Real estate | 1998 |
| British GAS Services Limited | Other services | 1995 |
| British GAS Trading Limited | Energy | 1995 |
| British Motor Holdings Limited | Professional & scientific | 1926 |
| Broadmead Estate Services Limited | Agriculture & fishing | 2001 |
| Brookes Property Consultancy Ltd | Real estate | 2024 |
| Browrich Limited | Extraterritorial | 1984 |
| Brunel Recruitment Limited | Construction | 2006 |
| BSB Ceramics Limited | Wholesale & retail | 1996 |
| Bscb Limited | Professional & scientific | 2005 |
| Bsria Limited | Professional & scientific | 2000 |
| Buckingham House Residents Association Limited | Households | 1994 |
| Bucks & Berks E.P.C's Limited | Professional & scientific | 2007 |
| Bucks Bodyworks Limited | Wholesale & retail | 2006 |
| Bull Developments (Maidenhead) Limited | Construction | 2006 |
| Business Analyst Masterminds Limited | Education | 2025 |
| Business Moves Limited | Transport & logistics | 1984 |
| Bussley Controls Limited | Construction | 1998 |
| Buzz IFA Limited | Financial services | 2003 |
| BWS Integration Limited | Information & communication | 2004 |
| Byron Factory Ltd | Information & communication | 2023 |
| C.F.Rawling & SON Limited | Wholesale & retail | 1977 |
| Cadability Thames Valley Ltd | Information & communication | 1999 |
| Cafetreatz Swansea Ltd | Hospitality | 2023 |
| Calm Healthcare Limited | Health & social care | 2013 |
| Camdata Systems Limited | Information & communication | 1999 |
| Campbell Flats Limited | Households | 2002 |
| Camway Properties Limited | Real estate | 1992 |
| Capulet House Management Company Limited | Real estate | 2009 |
| Careermakeover Limited | Professional & scientific | 2007 |
| Cargo Training International Limited | Education | 1992 |
| Carlos Investments Ltd | Real estate | 2007 |
| Caron Limited | Hospitality | 1999 |
| Carrara Pure Ltd | Information & communication | 2023 |
| Carter Consultants London Ltd | Professional & scientific | 2023 |
| Casi Group Limited | Other services | 2018 |
| Castle Electrodes Limited | Manufacturing | 1994 |
| Castle Meats (Burnham) Limited | Wholesale & retail | 2003 |
| Cavendish Building Services Limited | Administrative & support | 2003 |
| Cazador Limited | Professional & scientific | 2003 |
| CCV Telecom Ltd | Information & communication | 2006 |
| CDT Associates Limited | Information & communication | 2005 |
| Celebration Limited | Professional & scientific | 1994 |
| Cell Farm Residents Association Limited | Hospitality | 1999 |
| Celltech Group Limited | Professional & scientific | 1987 |
| Celltech Pension Trustees Limited | Financial services | 1993 |
| Celltech R&D Limited | Professional & scientific | 1980 |
| Centre Forward Marketing Promotions Limited | Professional & scientific | 1997 |
| Centrica Energy Limited | Wholesale & retail | 1993 |
| Centrica LNG Company Limited | Mining & quarrying | 2007 |
| Centrica Overseas Holdings Limited | Administrative & support | 2000 |
| Centrica PLC | Energy | 1995 |
| Chamberhouse Mill Management Company Limited | Households | 1975 |
| Chanelle Mccoy CBD UK Ltd | Manufacturing | 2019 |
| Charles Wilson School & Library Booksellers Limited | | 1993 |
| Chartdata Limited | Administrative & support | 2003 |