| Bannister Green Limited | Information & communication | 2017 |
| Bar House Events Ltd | Hospitality | 2021 |
| Bardfield Green Oak Limited | Construction | 2021 |
| Bardfield Montessori Day Nursery Ltd | Education | 2020 |
| Barista BOY Coffee Co Ltd | Wholesale & retail | 2023 |
| Barkers Canine Grooming Limited | Other services | 2015 |
| Barn Babies (Thaxted) Limited | Extraterritorial | 2000 |
| Barn Services Limited | Hospitality | 2007 |
| Barnards Investments Limited | Financial services | 2017 |
| Barnards Management Limited | Households | 2015 |
| Barnes Classic Cars Limited | Wholesale & retail | 2016 |
| Barnes Electrical London Ltd | Construction | 2019 |
| Barnetson Place Management Limited | Real estate | 2015 |
| Barnston Holdings Limited | Financial services | 1980 |
| Batt Consulting Limited | Information & communication | 2012 |
| Bawi Services Ltd | Other services | 2017 |
| Baxgul Limited | Financial services | 2013 |
| Bay Door Limited | Wholesale & retail | 2020 |
| Bayleaf (LDN) Limited | Hospitality | 2025 |
| Bayleaf Dunmow Ltd | Hospitality | 2019 |
| BB Welding & Engineering Ltd | Professional & scientific | 2026 |
| BCP2024 Limited | Households | 2024 |
| Beacon Partners Limited | Professional & scientific | 2026 |
| Bear Limited | Extraterritorial | 2002 |
| Beattie Building Controls Ltd | Construction | 2024 |
| Bedec Investments Ltd | Real estate | 2018 |
| Bedec Products Limited | Manufacturing | 1995 |
| Bedford Transmissions Limited | Manufacturing | 1980 |
| Bedford Travel Management Limited | Professional & scientific | 1992 |
| Beech Agency Limited | Wholesale & retail | 2006 |
| Beechall Electrical Services Ltd | Construction | 2019 |
| Bella Rose Management Limited | Real estate | 2025 |
| Belle Car Transporters & Specialised Trailers Limited | Manufacturing | 1991 |
| BEN P London Taxi Service Limited | Transport & logistics | 2015 |
| Benfleet Plastic Warehouse Limited | Wholesale & retail | 2011 |
| Bert Estimating Limited | Professional & scientific | 2025 |
| Bespoke Recruitment Holdings Limited | Administrative & support | 2004 |
| Bestronic Limited | Wholesale & retail | 2014 |
| Bethel Medical Limited | Health & social care | 2010 |
| Beyond Complexion Aesthetics Ltd | Other services | 2026 |
| Bicyclezone Limited | Wholesale & retail | 2025 |
| Bigwave E-Comerce Ltd | Wholesale & retail | 2025 |
| Bilby Property Limited | Real estate | 2019 |
| Binzscareuk Ltd | Health & social care | 2021 |
| Bizolla Ltd | Information & communication | 2023 |
| Black Barn Electrical Ltd | Construction | 2018 |
| Black Greyhound Solutions Limited | Construction | 2015 |
| Black Swan Furniture Ltd | Manufacturing | 2019 |
| Blackforge TCG Ltd | Wholesale & retail | 2026 |
| Blacklaws Consulting Ltd | Professional & scientific | 2019 |
| Blair Consulting Ltd | Professional & scientific | 2015 |
| Blast OFF Digital Ltd | Information & communication | 2021 |
| Blessen Developments Limited | Professional & scientific | 2021 |
| Block D Dellow Close Limited | Real estate | 2003 |
| Blockbond Limited | Other services | 1996 |
| Blooms Facials and Aesthetics Limited | Other services | 2024 |
| Blue Dog Properties (UK) Limited | Real estate | 2006 |
| Blue Dog Property Rentals Limited | Real estate | 2021 |
| Blue Lead Limited | Real estate | 2015 |
| Bluebell Architectural & Design Products Ltd | Construction | 2005 |
| Bluebell Music Studios Limited | Information & communication | 2024 |
| Bluegates Business Park Management Co Limited | Real estate | 2024 |
| Bluroc Projects Limited | Professional & scientific | 2023 |
| Blythcarr Property Limited | Construction | 2018 |
| BME Laser Techniques Ltd | Manufacturing | 2022 |
| BO Trade Limited | Professional & scientific | 2013 |
| Boars Head Tavern Limited | Hospitality | 2005 |
| Boat Safe Surveys Limited | Transport & logistics | 2009 |
| Body Worx Dunmow Limited | Wholesale & retail | 2014 |
| Bohemian Apparel Ltd | Wholesale & retail | 2019 |
| Bonadie Equestrian Centre Ltd | Agriculture & fishing | 2023 |
| Bonag Resources Limited | Construction | 2018 |
| Bordon Book Exchange Limited | Wholesale & retail | 2019 |
| Bowyer Lawrence Properties Ltd | Real estate | 2020 |
| Boyton Cross Motors Limited | Wholesale & retail | 2006 |
| Brand Evolve Ltd | Professional & scientific | 2022 |
| Brandstand United Kingdom Co., Ltd | Professional & scientific | 2013 |
| Bravura Construction Ltd | Construction | 2018 |
| Breagha Craft Ltd | Construction | 2026 |
| Breeze Office Solutions Limited | Wholesale & retail | 2009 |
| Breeze Property Management Limited | Extraterritorial | 1997 |
| Breezy Kids Limited | Education | 2017 |
| Brennans Meters Ltd | Administrative & support | 2017 |
| Brentwood Coaches Limited | Extraterritorial | 2025 |
| Brentwood M & E Services Limited | Construction | 2004 |
| Brevanto Administration Ltd | Administrative & support | 2025 |
| Brewington Media Ltd | Professional & scientific | 2021 |
| Brick House Consulting Ltd | Construction | 2024 |
| Bricks and Bits Ltd | Wholesale & retail | 2026 |
| Bright Bite Limited | Health & social care | 2008 |
| Brizoll UK Limited | Wholesale & retail | 2024 |
| Broadfields Garage Limited | Wholesale & retail | 2008 |
| Brocks Wheel & Tyre Ltd | Wholesale & retail | 2012 |
| Brownswood Park Tavern Limited | Hospitality | 2011 |
| Broxted Plant Hire Limited | Other services | 2012 |
| Bryonze Consultants Limited | Financial services | 2013 |
| Buildmyskitripcom Ltd | Administrative & support | 2013 |
| Bulldog Plant & Equipment Ltd | Manufacturing | 2021 |
| Bullet Brickwork UK Limited | Construction | 2009 |
| Burgoyne Motors Limited | Wholesale & retail | 2015 |