| Build Alert Limited | Information & communication | 2026 |
| Build Gold Limited | Other services | 2024 |
| Build My Property Ltd | Construction | 2017 |
| Build Pros Agency Limited | Other services | 2024 |
| Buildacre Limited | Construction | 2025 |
| Buildcor Limited | Construction | 2024 |
| Building & Compliance Ltd | Construction | 2018 |
| Building Maintenance SW Ltd | Construction | 2020 |
| Building Top Ltd | Construction | 2023 |
| Buildlec Construction Ltd | Construction | 2015 |
| Buildsolv Ltd | Construction | 2023 |
| Buksluxe Ltd | Wholesale & retail | 2024 |
| Bulai Limited | Transport & logistics | 2015 |
| Bulaiitservices Ltd | Manufacturing | 2026 |
| Bulat Painting & Decorating Limited | Construction | 2014 |
| Bulat UK Ltd | Construction | 2018 |
| Bulba V&N Limited | Construction | 2023 |
| Bullrunmarketing Ltd | Professional & scientific | 2025 |
| Bullseye Cars Limited | Transport & logistics | 2024 |
| Bully&Dav Ltd | Transport & logistics | 2025 |
| Bumble BEE Property Investment Limited | Real estate | 2026 |
| Bumbu Ltd | Construction | 2020 |
| Burelec Limited | Construction | 2012 |
| Burewalians Ltd | Hospitality | 2021 |
| Burger Street Ltd | Hospitality | 2017 |
| Burgers&Beyond Ltd | Hospitality | 2025 |
| Burke & SON Electrical Ltd | Construction | 2023 |
| Burnham on Crouch Tree Suppliers Limited | Agriculture & fishing | 2023 |
| Burns Contracting Limited | Professional & scientific | 2020 |
| Burns Utilities Ltd | Construction | 2022 |
| Burnt Mills MOT Test Centre Limited | Wholesale & retail | 2013 |
| Burst of Quintessence Ltd | Hospitality | 2024 |
| Bursted Manor Riding Centre Ltd | Arts & recreation | 2011 |
| Bushido Apparel Limited | Information & communication | 2021 |
| Busi Consultancy Ltd | Professional & scientific | 2019 |
| Business Lettings Limited | Real estate | 2015 |
| Business Support and IT Solutions Ltd | Administrative & support | 2023 |
| Busy Bees (Accommodation Bureau) Limited | Hospitality | 1976 |
| Butts Green Garden Centre and Cafe Ltd | Wholesale & retail | 2013 |
| Buzz Financial Services Ltd | Extraterritorial | 2020 |
| Buzz Jacks Waste Management Ltd | Water & waste | 2023 |
| Buzzfinchtech Ltd | Information & communication | 2025 |
| Bvardon Ltd | Health & social care | 2019 |
| Bvbagri Foods Corporation Limited | Hospitality | 2025 |
| Bvic Utilities Ltd | Construction | 2019 |
| BVS Contractors Ltd | Construction | 2025 |
| BW 37 Limited | Hospitality | 2021 |
| BW Accountancy Ltd | Professional & scientific | 2025 |
| BW Construction Skills & Consultancy Services Limited | Education | 2024 |
| BW Visuals Ltd | Professional & scientific | 2026 |
| BWA Logistics Limited | Transport & logistics | 2004 |
| BWK Limited | Other services | 2022 |
| BY. Stephen Cherry Limited | Other services | 2019 |
| Byford Group Ltd | Manufacturing | 2022 |
| Byrne & Co Plant Cleaning Limited | Administrative & support | 1995 |
| Byrne Building & Maintenance Services Limited | Construction | 2012 |
| Byruth Ltd | Health & social care | 2022 |
| Byteboost Consulting Ltd | Information & communication | 2024 |
| Byteshake Ltd | Professional & scientific | 2020 |
| Bytex Systems Ltd | Information & communication | 2025 |
| C & a Contracts Limited | Construction | 2014 |
| C & C Plumbing & Electrical Limited | Construction | 2005 |
| C & D Projects Limited | Professional & scientific | 2019 |
| C & F Maintenance Services Limited | Administrative & support | 2021 |
| C & G Plumbing & Bathrooms Ltd | Wholesale & retail | 2009 |
| C & H Communications Ltd | Information & communication | 2020 |
| C & L Crystal Cleaning Limited | Manufacturing | 2009 |
| C & L Recruitment and Training Limited | Administrative & support | 2020 |
| C & S Services (Essex) Ltd | Water & waste | 2025 |
| C a Design & Installations Ltd | Construction | 2008 |
| C a Plant & Materials Supplies Limited | Administrative & support | 2007 |
| C and L Containers 1 Limited | Administrative & support | 2025 |
| C and L Containers 2 Limited | Administrative & support | 2025 |
| C Brunger Electrical Limited | Construction | 2011 |
| C C C Management Company Limited | Other services | 2011 |
| C E Bartlett Enterprises Limited | Health & social care | 2020 |
| C Hewitt Training and Consultancy Limited | Administrative & support | 2022 |
| C J W Welding & Fabrication Limited | Manufacturing | 2017 |
| C M E Services Limited | Construction | 2016 |
| C P S Rail Ltd | Manufacturing | 2007 |
| C Taylors Floristry Limited | Other services | 2023 |
| C&B Property Managements Essex Ltd | Construction | 2026 |
| C&C International Limited | Wholesale & retail | 2019 |
| C&H Rental Ltd | Real estate | 2024 |
| C&N Site Services Ltd | Construction | 2016 |
| C&T MAT Ltd | Transport & logistics | 2020 |
| C-Force Projects Ltd | Construction | 2017 |
| C.Arthur Construction Ltd | Construction | 2016 |
| C.E.L Build Ltd | Construction | 2016 |
| C.H. Contractors (Essex) Limited | Construction | 2023 |
| C.J.R. Electrical Limited | Construction | 1986 |
| C.P. Construction Company Limited | Wholesale & retail | 1985 |
| C.V Carpenter Ltd | Construction | 2026 |
| C1 Creative Limited | Arts & recreation | 2022 |
| C360 Ltd | Real estate | 2016 |
| C453 Consultants Ltd | Professional & scientific | 2026 |
| C@Pital Consulting Ltd | Professional & scientific | 2024 |
| CA Recruitment Limited | Administrative & support | 2026 |
| Caadi Ltd | Construction | 2024 |
| Cableborder Limited | Professional & scientific | 1958 |