| Autowatch UK Limited | Wholesale & retail | 1993 |
| Autumn Engineering Limited | Agriculture & fishing | 1979 |
| AV Trinity Limited | Financial services | 1986 |
| AVA Shipping Ltd | Water & waste | 2024 |
| Avanti Apartments Limited | Administrative & support | 1999 |
| Aveley Trading Co Limited | | 1989 |
| Avelor Trading Limited | Wholesale & retail | 2026 |
| Avenue Sales and Marketing Limited | Administrative & support | 1999 |
| Avenue Tandoori Ltd | Hospitality | 2019 |
| Avenue UK Limited | Professional & scientific | 2002 |
| Aveyron Enterprises Limited | Professional & scientific | 2010 |
| Aviation Consultancy & Engineering Services Ltd | Professional & scientific | 2001 |
| Avondale Consulting Limited | Information & communication | 2018 |
| Avsons Financial Limited | Financial services | 2005 |
| Axecrest Estates Limited | Real estate | 2001 |
| Ayaz Deniz Limited | Hospitality | 2018 |
| Aylesford Pottery Ltd | Wholesale & retail | 2004 |
| Aylesford School of Ceramics Ltd | Education | 2007 |
| AYM (Services) Limited | Construction | 2011 |
| AYM Group Ltd | Professional & scientific | 2011 |
| AZ Sports Insights Ltd | Arts & recreation | 2024 |
| Azores Consulting Ltd | Information & communication | 2019 |
| Azow Music Limited | Information & communication | 1984 |
| Azra Catering Limited | Hospitality | 2001 |
| Aztec Engineering (Charing) Limited | Manufacturing | 2006 |
| Aztec Scaffolding Limited | Construction | 2000 |
| B & B Components Limited | Wholesale & retail | 2003 |
| B & E Associates | | 1994 |
| B a Textiles Limited | Transport & logistics | 1992 |
| B J Rice LP | | 1986 |
| B K Knight Limited | Construction | 2002 |
| B R Holland & Sons Limited | Administrative & support | 2002 |
| B Rice & Co | Professional & scientific | 1986 |
| B-Aviation Limited | Transport & logistics | 2006 |
| B. Tynan Contractors Limited | | 1979 |
| B. Wingate Limited | Information & communication | 2002 |
| B.A. Supplies & Services Limited | Other services | 1998 |
| B.C.L. Contracting Limited | Wholesale & retail | 1997 |
| B.H. Broadbent Building Limited | Construction | 2003 |
| B.I. Management Services Limited | | 1976 |
| B.J.Ellis & Partners Limited | Real estate | 1970 |
| B.M.R. Builders & Suppliers Limited | | 1982 |
| B.R. Pusser & Co. Ltd. | Professional & scientific | 2002 |
| B.T. Express Limited | Transport & logistics | 1988 |
| B2B Insights Limited | Professional & scientific | 2006 |
| B41LEY INV Limited | Financial services | 2019 |
| Babaprecious Ltd | Professional & scientific | 2014 |
| Babylon Farm Limited | Administrative & support | 1989 |
| Babylonia Properties Limited | Real estate | 2021 |
| Bachanal Limited | Extraterritorial | 2005 |
| Back on Track Children's Services Ltd | Health & social care | 2011 |
| Badger Installations Limited | Construction | 1998 |
| Badiani & Company Limited | Wholesale & retail | 1978 |
| Baggins Book Bazaar Limited | Wholesale & retail | 1987 |
| Bahavathy Ltd | Real estate | 2024 |
| Bahrams Developments Limited | Real estate | 2007 |
| Bahrams Ltd | Professional & scientific | 2003 |
| Baig Associates Ltd | Administrative & support | 2017 |
| Bailbrook Limited | Households | 1985 |
| Bailey ALL Build Ltd | Construction | 2025 |
| Bailey Wighton Limited | Wholesale & retail | 1958 |
| Bains Construction Limited | Construction | 1996 |
| Bains Property Holdings Ltd | Real estate | 2020 |
| Baker Close Management Company Limited | Other services | 2016 |
| BAL Cakery Ltd | Manufacturing | 2019 |
| Baldocks (Kent) Limited | | 1949 |
| Balon James Limited | Real estate | 1995 |
| Bamons Consulting Limited | Professional & scientific | 2012 |
| Banbury Flooring | | 1986 |
| Bangs Hair Ltd | Other services | 2018 |
| Bansal Services Limited | Administrative & support | 2006 |
| Banyard Competency and Training Limited | Professional & scientific | 2024 |
| Barakah Kitchen Ltd | Hospitality | 2021 |
| Barakel Services Ltd | Administrative & support | 2016 |
| Barbelo Limited | Manufacturing | 2002 |
| Barkingside Limited | Professional & scientific | 2025 |
| Barky Instruments International Limited | Professional & scientific | 1977 |
| Barley MOW Gifts & Interiors Ltd | Wholesale & retail | 2003 |
| Barnies Limited | Education | 2003 |
| Barnmead Road Management Company Limited | Extraterritorial | 1999 |
| Barrie Cope Limited | Hospitality | 1987 |
| Barrier Steel Fabrications Limited | Manufacturing | 1988 |
| Barryesta Ltd | Hospitality | 2024 |
| Basher 3 Limited | Real estate | 2001 |
| Bashman Property Services Ltd | Real estate | 2023 |
| Battys Floating Plant and Marine Services Limited | | 1982 |
| Bavarian Motorsport Limited | | 1982 |
| Baxall Construction EOT Limited | Administrative & support | 2020 |
| Baydis Properties Limited | Real estate | 1998 |
| Bayeux Developments Limited | Construction | 2007 |
| Baytech Communications Limited | Information & communication | 1998 |
| BB7 Consulting Limited | Professional & scientific | 2021 |
| BB7 Fire Limited | Professional & scientific | 2009 |
| BB7 Group Limited | Financial services | 2019 |
| BB7 Holdings Limited | Financial services | 2019 |
| BBM Care Limited | Health & social care | 2025 |
| BCH Builders Limited | Construction | 2003 |
| BCS Surface Coatings Limited | | 1988 |
| Bearwood Warley Limited | Real estate | 1997 |
| Beaudem Properties Ltd | Other services | 1999 |