| Binary-Direct Ltd | Transport & logistics | 2017 |
| Binder Property Services Ltd | Real estate | 2021 |
| Binge Gourmet by the Foot Limited | Hospitality | 2020 |
| Binnacle Ltd | Administrative & support | 2018 |
| Bino Ltd | Hospitality | 2021 |
| BIO Green UK Limited | Water & waste | 2008 |
| Bioanimal Health Limited | Professional & scientific | 1997 |
| Biocredit Limited | Professional & scientific | 2023 |
| Biomedical Aesthetics Ltd | Other services | 2024 |
| Biosatmya Ltd | Health & social care | 2025 |
| Birago Ltd | Hospitality | 2019 |
| Birca Construction Group Limited | Construction | 2015 |
| Birca Property Limited | Real estate | 2025 |
| Birch Construction Build Ltd | Construction | 2024 |
| Birch Farms (C & N) LLP | | 2016 |
| Birch Properties Limited | Construction | 1972 |
| Birchland (East Anglia) Ltd | Real estate | 2020 |
| Birchwood Contracts Ltd | Agriculture & fishing | 2019 |
| Birchwood East Ltd | Construction | 2006 |
| Birchwood Farm Shop Limited | Wholesale & retail | 2007 |
| Bird and Sons (EFT) Limited | Wholesale & retail | 2024 |
| Bird Building & Landscaping Limited | Administrative & support | 2012 |
| Bird Roofing Limited | Construction | 2016 |
| Birds Farm Cottages Ltd | Hospitality | 2024 |
| Birds Farm Holiday Lets Ltd | Hospitality | 2024 |
| Birkett Long IFA LLP | | 2013 |
| Birts Properties Ltd | Real estate | 2024 |
| Bishop's Walk NO. 2 (Broad Street ELY) Management Company Limited | Households | 2001 |
| Bishop@Catering Limited | Hospitality | 2023 |
| Bishops Twelve Limited | Hospitality | 2024 |
| Bishops Walk Developments Ltd | Real estate | 2011 |
| Bistro Thirty SIX Ltd | Hospitality | 2025 |
| Bite MEE Ltd | Hospitality | 2024 |
| Bitnexus Ltd | Information & communication | 2024 |
| Bitransport Limited | Transport & logistics | 2019 |
| Biucac Limited | Education | 2020 |
| Bivic Limited | Administrative & support | 2022 |
| BIZ Retreats Ltd | Administrative & support | 2023 |
| BJ Catering Limited | Hospitality | 2024 |
| BJ Cuisine Limited | Hospitality | 2021 |
| BJ Support Ltd | Information & communication | 2025 |
| BJB Colchester Ltd | Hospitality | 2020 |
| BJB Professional Services Limited | Real estate | 2013 |
| BJB Roofing Limited | Construction | 2006 |
| BJG Priory Ltd | Financial services | 2023 |
| BJH Essex Ltd | Construction | 2016 |
| BJK Holding Chelmsford Limited | Wholesale & retail | 2022 |
| BK Building Contractors Limited | Construction | 2022 |
| BK Maintenance Services Ltd | Construction | 2020 |
| Bkbs Property Ltd | Real estate | 2020 |
| BKK Fighters Colchester Ltd | Arts & recreation | 2020 |
| BKM Mannesmann (Essex) Ltd. | Construction | 2018 |
| BKM Mannesmann UK Ltd | Construction | 2015 |
| BKT Motor Services Limited | Wholesale & retail | 2002 |
| BL Express Ltd | Transport & logistics | 2024 |
| Blabox Limited | Wholesale & retail | 2022 |
| Black & White Staffing Solutions Limited | Real estate | 2016 |
| Black and White Barbers 25 Ltd | Other services | 2025 |
| Black Bear Tattoo Studios Ltd | Other services | 2021 |
| Black Brook Theatre Ltd | Arts & recreation | 2026 |
| Black Drum Solutions Limited | Professional & scientific | 2015 |
| Black Eagle Building and Construction Ltd | Construction | 2017 |
| Black FOX Letting Ltd | Real estate | 2023 |
| Black FOX Property Development Limited | Real estate | 2026 |
| Black HAT Cleaning Services Ltd | Administrative & support | 2025 |
| Black HAT Functions Ltd | Hospitality | 2026 |
| Black Hope Tattoo Limited | Arts & recreation | 2018 |
| Black Lime Ltd | Wholesale & retail | 2025 |
| Black Moth Tattoo's Ltd | Other services | 2018 |
| Black Oyster Ltd | Information & communication | 2020 |
| Black Sheep Developments Ltd | Construction | 2025 |
| Blackacre (Great Blakenham) 2 Limited | Other services | 2022 |
| Blackacre (Great Blakenham) 3 Limited | Real estate | 2021 |
| Blackacre (Great Blakenham) Ltd | Construction | 2014 |
| Blackbrook Cottages Ltd | Hospitality | 2022 |
| Blackbrook Kennels & Cattery Limited | Administrative & support | 2003 |
| Blackbrook Page Limited | Professional & scientific | 2024 |
| Blackbrook Veen Ltd | Administrative & support | 2025 |
| Blackheath Carpentry Contractors Ltd | Manufacturing | 2026 |
| Blackheath Carpet Sales Limited | Wholesale & retail | 2003 |
| Blackheath Management Co Limited | Households | 1988 |
| Blackheath Plumbing & Heating Limited | Construction | 2026 |
| Blackiceberg Ltd | Other services | 2010 |
| Blackjack Engineers Limited | Professional & scientific | 2015 |
| Blackleaf Automotive Ltd | Wholesale & retail | 2025 |
| Blackline Safety Europe Ltd | Wholesale & retail | 2012 |
| Blackman Surveyors LLP | | 2008 |
| Blackstone Contractors Limited | Construction | 2005 |
| Blackstone Leisure Ltd | Wholesale & retail | 2018 |
| Blackthorn Gaming Limited | Financial services | 2025 |
| Blackwater & Essex Chimney Sweeps Ltd | Administrative & support | 2022 |
| Blackwater Advertising Ltd | Information & communication | 2026 |
| Blackwater Financial Holdings Limited | Administrative & support | 2016 |
| Blackwater Financial Limited | Financial services | 2016 |
| Blackwater Fishing Limited | Agriculture & fishing | 2010 |
| Blackwater Gym Solutions Ltd | Administrative & support | 2025 |
| Blackwater Plumbing & Heating Ltd | Construction | 2025 |
| Blackwater Property (Essex) Limited | Real estate | 2019 |
| Blackwater Reach (Southminster) Management Company Limited | Households | 2019 |
| Blackwell Automation Ltd | Manufacturing | 2018 |