| Bradley Building (Essex) Ltd | Construction | 2018 |
| Bradley Construction Ltd | Construction | 2015 |
| Brady's Seafood Stall Limited | Administrative & support | 2016 |
| Braestone Construction Ltd | Construction | 2019 |
| Braestone Developments Ltd | Construction | 2021 |
| Braestone Essex Ltd | Construction | 2022 |
| Braestone Landscaping Ltd | Administrative & support | 2021 |
| Brain and Behaviour Academy Ltd | Education | 2025 |
| Brakespark Limited | Construction | 2022 |
| Brambles Care Home Ltd | Health & social care | 2003 |
| Bramley Hire Ltd | Administrative & support | 2017 |
| Branch Company Limited | Real estate | 1998 |
| Brand Property Portfolios Ltd | Real estate | 2021 |
| Brandrx Limited | Professional & scientific | 2025 |
| Brannans (Southend) Limited | Extraterritorial | 1988 |
| Brausch & Co (UK) Limited | Wholesale & retail | 1985 |
| Bravespace Limited | Public administration | 2022 |
| Breeze Residential Property Management Limited | Households | 2024 |
| Brentwood Social Limited | Hospitality | 2013 |
| Brentwood Wellness Centre Ltd | Health & social care | 2022 |
| Brescia House Management Company Ltd | Households | 2019 |
| Brew Communications Limited | Professional & scientific | 2019 |
| Brian Curtis Limited | Construction | 2003 |
| Brian Nuttgens Accountants Limited | Other services | 2002 |
| Bricks and Mortar Consulting Limited | Construction | 2015 |
| Brickwise Building Company Limited | Construction | 2021 |
| Bridge FX Limited | Professional & scientific | 2013 |
| Bridgemore Capital Ltd | Financial services | 2023 |
| Bridgemore Mortgages Ltd | Financial services | 2025 |
| Bridgewater Blinds Limited | Manufacturing | 2004 |
| Bridgwaters Bedroom and Home Office Ltd | Construction | 2020 |
| Briggs Investments Limited | Financial services | 2025 |
| Bright Bizz Partnership LLP | | 2022 |
| Bright Side Park Homes Limited | Other services | 2023 |
| Bright Site Developments Ltd | Professional & scientific | 2019 |
| Brightduct Insulations Ltd | Construction | 2021 |
| Brightlife Ltd | Wholesale & retail | 2018 |
| Brightnest Cleaning Ltd | Administrative & support | 2025 |
| Brightr Ltd | Administrative & support | 1998 |
| Brights Keys Limited | Extraterritorial | 2012 |
| Brights Security Limited | Administrative & support | 2012 |
| Brightside Renewables Ltd | Construction | 2023 |
| Brilliant Parents Limited | Administrative & support | 2017 |
| Britannia Drywall Limited | Construction | 2014 |
| Britannia Property (London) Limited | Extraterritorial | 2017 |
| Britannia Property Partners Limited | Real estate | 2024 |
| Britannia Refurbishments Limited | Construction | 2015 |
| Britannia Safety Limited | Wholesale & retail | 2014 |
| Britenergy Group Limited | Professional & scientific | 1999 |
| Britnrg Limited | Mining & quarrying | 2020 |
| Brizmo Limited | Professional & scientific | 2006 |
| BRO2HER Ltd | Arts & recreation | 2024 |
| Broadfields Building Services Limited | Construction | 2005 |
| Broadfields Construction Limited | Construction | 2024 |
| Broadway Property LET Limited | Real estate | 2016 |
| Brocadeon Limited | Manufacturing | 2011 |
| Brocklebank Housing Ltd | Real estate | 2017 |
| Broekman and Associates Limited | Professional & scientific | 2015 |
| Brooklyn Electrical Limited | Construction | 2011 |
| Brooks Care and Nursing Services Limited | Health & social care | 2008 |
| Brooks Carpentry & Joinery Ltd | Manufacturing | 2020 |
| Brooks Nova Holdings Ltd | Financial services | 2026 |
| Brooks Nova Ltd | Real estate | 2024 |
| Brooks Vehicle Technicians Limited | Wholesale & retail | 2020 |
| Brookson (5058J) Limited | Administrative & support | 2007 |
| Broomfield (Westcliff) Heating Limited | Construction | 2009 |
| Brows by Sacha Ltd | Other services | 2022 |
| BRR Properties Ltd | Real estate | 2024 |
| Bruce Media Group Ltd | Professional & scientific | 2024 |
| Bruin Technical Ltd | Arts & recreation | 2019 |
| Brunton Welding Ltd | Professional & scientific | 2023 |
| BRW Properties Ltd | Real estate | 2020 |
| Bryant Construction Ltd | Construction | 2025 |
| Bryce Meadows Limited | Other services | 2002 |
| BS Metering - Pools Team Limited | Other services | 2025 |
| BST Scaffolding Ltd | Construction | 2013 |
| BTM Installations Ltd | Construction | 2021 |
| Bttmm Limited | Construction | 2011 |
| Bubble Image Ltd | Information & communication | 2018 |
| Buccaneers IHC Limited | Arts & recreation | 2024 |
| Buckingham Contractors Limited | Construction | 2008 |
| Buckley Watson Holdings Limited | Financial services | 2025 |
| Bucks Cheese GUY Limited | Wholesale & retail | 2024 |
| Buddha Bar Gallery & Interiors Limited | Wholesale & retail | 2024 |
| Buddha Belly 888 Ltd | Hospitality | 2026 |
| Buddha Belly Take Away Ltd | Hospitality | 2025 |
| Buddha Belly Thai Leigh Limited | Hospitality | 2024 |
| Buddy Construction Ltd | Construction | 2025 |
| Buggle Limited | Information & communication | 2018 |
| Build Skill - Plus Ltd | Education | 2013 |
| BUILD247 Construction Limited | Construction | 2025 |
| Buildfixmaintain Ltd | Construction | 2025 |
| Building Line Limited | Construction | 2019 |
| Building Services Essex Ltd | Construction | 2015 |
| Buildwell Consultancy Ltd | Professional & scientific | 2016 |
| Bulk Powers Ltd | Wholesale & retail | 2020 |
| Bull Corringham PH Limited | Hospitality | 2021 |
| Bull-Betts Decor Ltd | Construction | 2015 |
| Bulwark Road Investments Limited | Real estate | 2020 |
| Bump to Balance Ltd | Health & social care | 2024 |