| BHG (Witham) Ltd | Wholesale & retail | 2026 |
| Bifs Holdings Limited | Financial services | 2025 |
| Big Splash Cleaning Services Limited | Administrative & support | 2012 |
| Bigflame Limited | Real estate | 2012 |
| Bill Childs Plant Services, Essex | | 1988 |
| Binnington Limited | Hospitality | 2017 |
| Birra DI Cesare Ltd | Wholesale & retail | 2025 |
| BJV Constructions Limited | Construction | 2009 |
| BKL Security Limited | Extraterritorial | 2019 |
| Black Knight Supplements Ltd | Manufacturing | 2012 |
| Black River Accountancy Limited | Professional & scientific | 2014 |
| Blackbrook Capital Limited | Real estate | 2019 |
| Blackcroft Management Limited | Real estate | 2014 |
| Blackhorse Distribution Limited | Extraterritorial | 1986 |
| Blackwater Health and Fitness Limited | Arts & recreation | 2014 |
| Blackwell Electrical Limited | Construction | 2007 |
| Blade Electrical Ltd | Construction | 2012 |
| Blake Dental Limited | Health & social care | 2021 |
| Blanc Investment Ltd | Real estate | 2024 |
| Blenheim Grove Developments (Camberwell) Limited | Real estate | 2004 |
| Bloomsburys Art Cafe Limited | Hospitality | 2022 |
| Blossom Florists Limited | Wholesale & retail | 2010 |
| Blossoms Send CIC | Education | 2025 |
| BLU Screen Limited | Administrative & support | 2014 |
| Blue Flag Construction Limited | Real estate | 2005 |
| Bluelinelashes Ltd | Other services | 2024 |
| Bluerose Enterprise Limited | Professional & scientific | 2014 |
| BMC Pharma Limited | Health & social care | 2025 |
| Bnorm Ltd | Real estate | 2019 |
| Bobald Ventures Limited | Financial services | 2021 |
| Bob’S Snacks Ltd | Manufacturing | 2026 |
| Bocking & Wood Property Investments Ltd | Real estate | 2022 |
| Bocking Blackwater Limited | Real estate | 2021 |
| Bojm Limited | Administrative & support | 2025 |
| Bollyver Holdings Ltd | Information & communication | 2024 |
| Bonnells Electrical Contractors Limited | Construction | 1988 |
| Boreham Leisure Properties Ltd | Real estate | 2017 |
| Borno Chemists Limited | Wholesale & retail | 1972 |
| Boss Key Ltd | Arts & recreation | 2022 |
| Bostwick Properties Limited | Real estate | 2021 |
| Boudoirbeauty Limited | Other services | 2016 |
| Bounce Home Limited | Financial services | 2018 |
| Bounce Network Limited | Financial services | 2017 |
| Bouncelife Limited | Financial services | 2015 |
| Boutique Baller Shops Limited | Administrative & support | 2019 |
| Bradley David Associates Limited | Administrative & support | 2022 |
| Braintree and Bocking Auctions Ltd | Wholesale & retail | 2020 |
| Braintree Flooring Limited | Construction | 2017 |
| Brand Transparency Limited | Professional & scientific | 2010 |
| Brantham Athletic Football Club Limited | Arts & recreation | 2016 |
| Brantham Management Community Interest Company | Administrative & support | 2006 |
| Braxted Building Limited | Construction | 2019 |
| Braxted Consultancy Ltd | Administrative & support | 2012 |
| Braxted Trustee 1 Limited | Administrative & support | 2020 |
| Braxted Trustee 2 Limited | Administrative & support | 2020 |
| Breadrin Limited | Manufacturing | 2020 |
| Breakpoint Courts & Sports Surfaces Limited | Construction | 2018 |
| Breeza Ltd | Transport & logistics | 2017 |
| Brentwood Town Football Club CIC | Arts & recreation | 2024 |
| Brereton Future Finance Ltd | Financial services | 2026 |
| Brian FU Limited | Health & social care | 2021 |
| Brice Aggregates Limited | Manufacturing | 2013 |
| Brice Properties Limited | Real estate | 2019 |
| Brickhaven Property Ltd | Real estate | 2025 |
| Bridge Rentals Limited | Real estate | 2018 |
| Bright Devs Assets Limited | Real estate | 2019 |
| Bright Future Developments Ltd | Real estate | 2018 |
| Brighter Projects Holdings Limited | Financial services | 2024 |
| Brighton Surveyors Ltd | Professional & scientific | 2014 |
| Bringey Holdings Limited | Administrative & support | 2023 |
| Brink Riley Properties Limited | Real estate | 2013 |
| Brinwick Commodity Brokers PVT Ltd | Professional & scientific | 2016 |
| Broderick Associates Ltd | Professional & scientific | 2014 |
| Brookend Veterinary Practice Ltd | Professional & scientific | 2014 |
| Brookend Veterinary Practice Trustees Ltd | Professional & scientific | 2025 |
| Brooklands International Freight Services Limited | Transport & logistics | 1990 |
| Brother Bear Media Ltd | Information & communication | 2016 |
| Brtk Holdings Limited | Real estate | 2024 |
| BSI Elec-N-Mech Limited | Manufacturing | 1995 |
| BSW Developments Ltd | Extraterritorial | 2020 |
| BTI Biotechnology UK Ltd | Health & social care | 2010 |
| Bubblescape Ltd | Hospitality | 2007 |
| Buckinghamshire Internet Services Limited | Professional & scientific | 1995 |
| Building Cleaning Services Ltd. | Administrative & support | 1983 |
| Built by People Ltd | Professional & scientific | 2000 |
| Burlington GB Group Ltd | Manufacturing | 2007 |
| Buteline International Limited | Professional & scientific | 1994 |
| Buteline UK Limited | Wholesale & retail | 2004 |
| BWG Planet Ltd | Professional & scientific | 2019 |
| C C Horticultural Services Limited | Administrative & support | 2006 |
| C J Patisserie Limited | Manufacturing | 2020 |
| C&O Travel Ltd | Transport & logistics | 2024 |
| C&R Builders Ltd | Construction | 2021 |
| C&S Landscapes & Maintenance Ltd | Administrative & support | 2025 |
| CA Industries Ltd | Professional & scientific | 2023 |
| Cabello Hair and Beauty (UK) Limited | Other services | 2014 |
| Cablers ITX Ltd | Information & communication | 2022 |
| Cablers Limited | Information & communication | 2001 |
| Cacao Shack Ltd | Wholesale & retail | 2025 |
| CAD Design (Essex) Limited | Professional & scientific | 2012 |