| Bellaudai Limited | Wholesale & retail | 2026 |
| Bellwether Boxing & Fitness Gym Ltd | Arts & recreation | 2022 |
| Belsa Limited | Real estate | 2025 |
| Belvisi Property Limited | Real estate | 2019 |
| Benefit Star Limited | Professional & scientific | 2010 |
| Bennett Estates Limited | Professional & scientific | 2008 |
| Benybuilders Ltd | Construction | 2026 |
| Beorgan Security Consulting Ltd | Administrative & support | 2017 |
| Berry Best Produce Ltd | Manufacturing | 2017 |
| Bersca Ltd | Administrative & support | 2022 |
| Bertie & Eugene Consulting Limited | Administrative & support | 2022 |
| Bespoke Laser Designs LP | | 2022 |
| Beta Shift Ltd | Information & communication | 2025 |
| Beth Wheeler Limited | Real estate | 2011 |
| Better Value International Ltd | Arts & recreation | 2023 |
| Betts Boutique Travel Ltd | Administrative & support | 2022 |
| Beven Legal Limited | Professional & scientific | 2021 |
| Bevington Sport Ltd | Arts & recreation | 2020 |
| Beyond Basil Limited | Extraterritorial | 2025 |
| Bfrs Property Group Ltd | Households | 2026 |
| Biasonic Enterprises Limited | Information & communication | 2014 |
| Bigfatstudio Limited | Information & communication | 1996 |
| Biggles Labelling Limited | Manufacturing | 1988 |
| Billabong Consulting Limited | Professional & scientific | 2013 |
| Binco Construction Ltd | Construction | 2024 |
| Biocrucible Ltd | Professional & scientific | 2018 |
| Biomodal Limited | Professional & scientific | 2012 |
| Bionomiq Limited | Professional & scientific | 2023 |
| Biophilia Limited | Professional & scientific | 2024 |
| Biospeedia SPV Ltd | Manufacturing | 2020 |
| Biotech Project Consulting Limited | Professional & scientific | 2014 |
| Birdflight Property Management Limited | Real estate | 1986 |
| Birdy's Ltd | Manufacturing | 2007 |
| Bishop's Stortford Sinfonia Ltd. | Arts & recreation | 2001 |
| Bishops Gray Rise Residents Management Company Limited | Households | 2008 |
| Bitter Thirst Production Limited | Arts & recreation | 2022 |
| Bizware Ltd | Information & communication | 2024 |
| BJM Group Ltd | Information & communication | 2012 |
| Bjwhackney Ltd | Construction | 2018 |
| BKD Holdings Limited | Other services | 2021 |
| Black Oak Installations Limited | Construction | 2024 |
| Black Planet Limited | Arts & recreation | 2021 |
| Black Pudding Developments Ltd | Construction | 2023 |
| Blenheim CT (Freehold) Limited | Real estate | 2026 |
| Blighter Surveillance Systems Limited | Manufacturing | 2015 |
| Bloodstock Notebook Ltd | Information & communication | 2021 |
| Blossom Barn Nursery at Great Chesterford Limited | Health & social care | 2025 |
| Blow UP Records Limited | Information & communication | 1996 |
| Blow UP Songs Limited | Information & communication | 2001 |
| Blowup Limited | Information & communication | 2003 |
| Blue Cat Construction Limited | Construction | 2023 |
| Blue Design Shed Ltd | Professional & scientific | 2014 |
| Blue HOP Limited | Hospitality | 2003 |
| Blue Ocean Projects Limited | Professional & scientific | 2004 |
| Blue Tree Carpentry Ltd | Construction | 2025 |
| Bluebird Ltd | Hospitality | 2015 |
| Bluecat Professional Audio Consultancy Limited | Administrative & support | 2009 |
| Blueprop Investments Ltd | Real estate | 2020 |
| Bluerun Limited | Construction | 1991 |
| Blues Property Group Ltd | Construction | 2019 |
| Blume Development Ltd | Education | 2026 |
| BM Design & Print Ltd | Professional & scientific | 2019 |
| Bmmlb Ltd | Real estate | 2019 |
| Boho Beach Fest Limited | Wholesale & retail | 2017 |
| BOK Solutions Ltd | Construction | 2011 |
| Boldturn Ltd | Information & communication | 2025 |
| Bone Machine Ltd | Arts & recreation | 2021 |
| Bonhams Barn BED & Breakfast Ltd | Hospitality | 2012 |
| Bonmark Properties Limited | Financial services | 1987 |
| Bonne Fire Box Ltd | Hospitality | 2018 |
| Book a Buffet Ltd | Hospitality | 2025 |
| Books and Moore Ltd | Professional & scientific | 2026 |
| Booksteps Limited | Professional & scientific | 2003 |
| Boompods Limited | Manufacturing | 2012 |
| Boost My PUB Ltd | Professional & scientific | 2014 |
| Boost! Design & Marketing Ltd | Professional & scientific | 2022 |
| Botana Ltd | Wholesale & retail | 2025 |
| Bottisham Heath Stud Limited | Administrative & support | 2001 |
| Bounce and Giggles Ltd | Administrative & support | 2026 |
| Boundy Consulting Ltd | Professional & scientific | 2020 |
| Bourne Industrial Services Limited | Professional & scientific | 1995 |
| Bowler DB Holdings Limited | Construction | 2022 |
| Bowler Holdings Limited | Construction | 2021 |
| Boxworth Consultants Limited | Administrative & support | 2006 |
| Boys British School Management Limited | Real estate | 2001 |
| BP Sporting Ltd | Arts & recreation | 2024 |
| BR Surveys Limited | Administrative & support | 2022 |
| Brainbox Webtech Ltd. | Professional & scientific | 2010 |
| Bramley Hollow Ltd | Construction | 2023 |
| Brand Intelligence Limited | Administrative & support | 2014 |
| Brand Tourist Limited | Professional & scientific | 2014 |
| Brandbus Limited | Administrative & support | 2009 |
| Brandwood Commercial Limited | Real estate | 2006 |
| Brandysnap Business Graphics Limited | Administrative & support | 2015 |
| Breadcrumb Marketing & Media Limited | Professional & scientific | 2016 |
| Breathe Holdings Limited | Real estate | 2021 |
| Breathe Investments Limited | Information & communication | 2021 |
| Breathewell.Life Ltd | Other services | 2010 |
| Bree Real Estate Limited | Administrative & support | 2024 |
| Brendan Fields Limited | Construction | 2000 |