| Bright Selection Ltd | Administrative & support | 2011 |
| Brightlingsea Aggregates Ltd | Wholesale & retail | 2021 |
| Brightlingsea Auto Centre Limited | Wholesale & retail | 2015 |
| Brightlingsea Boat Park & Ride Limited | Transport & logistics | 2005 |
| Brightlingsea Electrical Contractors Limited | Construction | 2016 |
| Brightlingsea Free Music Festival C.I.C. | Arts & recreation | 2025 |
| Brik Factory Ltd | Professional & scientific | 2024 |
| Brik Holdings Ltd | Financial services | 2026 |
| Brilliant Care Ltd | Health & social care | 2018 |
| Brimar Data & Power Solutions Limited | Professional & scientific | 2025 |
| Brimstone Place (Little Dunmow) Management Company Limited | Households | 2023 |
| Brindle Enterprises Limited | Information & communication | 2003 |
| Brinkley Grove (One) Management Company Limited | Households | 2005 |
| Brinkley Place (Colchester) Management Company Limited | Households | 1987 |
| Briony Lawton Consulting & Coaching Ltd | Professional & scientific | 2021 |
| Brirod Developments Limited | Construction | 2004 |
| Brit Coach Travels Ltd | Transport & logistics | 2026 |
| Britannia Bites Ltd | Wholesale & retail | 2023 |
| Britannia Gadgets Limited | Wholesale & retail | 2024 |
| Britannia Heating Ltd | Construction | 2025 |
| Britannia Innovation Group Limited | Information & communication | 2025 |
| Britannia Mews (Colchester) Ltd | Households | 2010 |
| Britannia Storage Management Ltd | Manufacturing | 2011 |
| Britannia Storage Systems Limited | Manufacturing | 1982 |
| Britau Scaffold Ltd | Construction | 2012 |
| Britesparkes Limited | Professional & scientific | 2016 |
| British Tyre Manufacturers' Association Limited | Other services | 1968 |
| British Women Pilots Association Limited | Other services | 2017 |
| Britswitch Limited | Administrative & support | 2022 |
| BRM Precision Engineers and Toolmakers Ltd | Real estate | 1988 |
| Broad Horizons Limited | Health & social care | 1998 |
| Broad Stripe Butchers Limited | Professional & scientific | 2000 |
| Broadbent Group Ltd | Information & communication | 2021 |
| Broadcast Video Solutions Limited | Information & communication | 2002 |
| Broadfield Motor Group Ltd | Wholesale & retail | 2020 |
| Broadland Real Estate Services Limited | Real estate | 2026 |
| Broadspeed Engineering Limited | Professional & scientific | 1994 |
| Broadspeed Limited | Wholesale & retail | 1994 |
| Broadview Marketing Ltd | Wholesale & retail | 2013 |
| Broham Energy Limited | Construction | 2026 |
| Broham Forecourt Developments Limited | Administrative & support | 1980 |
| Broham Holdings Limited | Financial services | 2015 |
| Broken Boys Club Ltd | Wholesale & retail | 2023 |
| Bromley & Hooke Limited | Real estate | 2023 |
| Bromley Automated Gates Ltd | Construction | 2025 |
| Bromley Coffee Ltd | Hospitality | 2023 |
| Bromley Fire Protection Ltd | Construction | 2019 |
| Bronbeck & Grace Limited | Other services | 2016 |
| Bronze Hill Consulting Ltd | Professional & scientific | 2011 |
| Brook and MAC Property Development Ltd | Construction | 2024 |
| Brook Farm Plant and Sales Limited | Manufacturing | 2018 |
| Brook House Health Ltd | Health & social care | 2014 |
| Brook Lodge (Colchester) Limited | Households | 2000 |
| Brookes Biomass Services Ltd | Manufacturing | 2025 |
| Brookhill Investments Limited | Professional & scientific | 2005 |
| Brooklyn House Limited | Health & social care | 2001 |
| Brooks Brothers Investments Limited | Real estate | 2025 |
| Brooks Property Rentals Limited | Real estate | 2026 |
| Brooks RE Consulting Limited | Administrative & support | 2016 |
| Broom Mortgages and Wealth Ltd | Financial services | 2021 |
| Broombriggs-Niton International (BNI) Limited | Professional & scientific | 2022 |
| Broome Brothers LLP | | 2016 |
| Broomfield Filling Station Limited | Real estate | 1949 |
| Bros Management Ltd | Construction | 2022 |
| Brotherman Apparel Ltd | Wholesale & retail | 2024 |
| Broton Construction Limited | Construction | 2018 |
| Brough Design Ltd | Professional & scientific | 2026 |
| Brown and White Ltd | Other services | 2007 |
| Brown K Limited | Wholesale & retail | 2006 |
| Brown Thornton Consulting Ltd | Professional & scientific | 2024 |
| Browns Building Developers Ltd | Construction | 2025 |
| Browns Construction & Groundworks Ltd | Construction | 2024 |
| Browns More Hair NOW Limited | Other services | 2004 |
| Browns Motor Parts Ltd | Wholesale & retail | 2026 |
| Brownsman Ventures Limited | Wholesale & retail | 2025 |
| Brows on Fleek Ltd | Other services | 2020 |
| Browser Media Ltd | Professional & scientific | 2005 |
| Brti Electrical Limited | Construction | 2012 |
| Bruce B Ltd | Construction | 2006 |
| Bruceboy Limited | Hospitality | 2017 |
| BRV Contractors Ltd | Professional & scientific | 2017 |
| Bryan Dale House Management Company Limited | Households | 2003 |
| Bryant O'Neill Wealth Management Limited | Financial services | 2014 |
| Brydon Financials Limited | Financial services | 2015 |
| BRZ Logistics Ltd | Transport & logistics | 2014 |
| BS Construction Ltd | Construction | 2025 |
| BSB Electrical Limited | Construction | 2015 |
| BSB Heating Ltd | Construction | 2012 |
| Bslive Ltd | Information & communication | 2025 |
| Bspke Limited | Manufacturing | 2023 |
| Bsquare Care Provision and Services Ltd | Health & social care | 2024 |
| BSW Contractors Limited | Administrative & support | 2001 |
| Bsww Ltd | Education | 2018 |
| Bszo Limited | Professional & scientific | 2024 |
| BT Proweld Ltd | Manufacturing | 2021 |
| BTB Site Management Limited | Professional & scientific | 2023 |
| BTC Motronics Limited | Manufacturing | 2005 |
| Bubble and PHO Ltd | Hospitality | 2017 |
| Bubble Tealicious Company Ltd | Wholesale & retail | 2021 |
| Bubbles Dog Grooming Ltd | Other services | 2020 |