| Barley Village Ballers Ltd | Education | 2025 |
| Barnaby and Sons Ltd | Construction | 2026 |
| Barnwell Lake Cafe Ltd | Construction | 2017 |
| Barry Alan (Holdings) Limited | Real estate | 1973 |
| Bartlow (Contracting) Limited | Agriculture & fishing | 2010 |
| Basement Textiles Limited | Manufacturing | 2007 |
| Bastian & Nelly Limited | Wholesale & retail | 2016 |
| Bathing Under the Sky Limited | Wholesale & retail | 2012 |
| Battledore Limited | Construction | 2006 |
| BB Bloodstock Limited | Agriculture & fishing | 2020 |
| BB Investor Company Limited | Real estate | 2017 |
| BBM Bodyworks Limited | Wholesale & retail | 2011 |
| BDW Beer and Wine Emporium Ltd | Wholesale & retail | 2010 |
| BE Aviation Services Limited | Professional & scientific | 2015 |
| BE Bougie Ltd | Wholesale & retail | 2024 |
| Bearded Bear Co Ltd | Manufacturing | 2024 |
| Beatrice Court Limited | Households | 2008 |
| Beauchamp Residents Association Limited | Households | 1986 |
| Beaufort Place Limited | Households | 1984 |
| Beaulands Close Management Limited | Households | 1977 |
| Beauty by Gwen Ltd | Other services | 2025 |
| Beechbarn Farming Limited | Agriculture & fishing | 2020 |
| Beechwood Estates & Development Ltd | Real estate | 1988 |
| Beechwood Estates (Harston) Ltd | Construction | 2018 |
| Befixed Ltd | Other services | 2023 |
| BEL Clinical Ltd | Professional & scientific | 2021 |
| Belisarius Advice Limited | Information & communication | 2016 |
| Bell College Court Freehold Limited | Households | 2017 |
| BEN Nevis Collective Ltd | Real estate | 2023 |
| Bennell Developments Ltd | Construction | 2017 |
| Bergamot Property Investment and Development Ltd | Real estate | 2021 |
| Bergsa Ltd | Professional & scientific | 2019 |
| Berry Accounting & Business Services Limited | Professional & scientific | 2002 |
| Beta-Vr Ltd | Information & communication | 2025 |
| Between Buns Ltd | Hospitality | 2021 |
| Between Buns Restaurant Ltd | Hospitality | 2025 |
| Beyond Measure Consulting Ltd | Professional & scientific | 2024 |
| BG Boiler Servicing Ltd | Construction | 2025 |
| Bidco Jupiter Limited | Financial services | 2022 |
| Bidwedge 4 Charitable Ventures Limited | Information & communication | 2019 |
| Bidwedge Limited | Other services | 2017 |
| Big Numbers Consulting Limited | Information & communication | 2023 |
| Big Skies Limited | Professional & scientific | 2003 |
| Billionaire Baby Project Ltd | Wholesale & retail | 2024 |
| BIO PM Limited | Professional & scientific | 2017 |
| Bioforgeuk Ltd | Professional & scientific | 2025 |
| Bioresonance Tech Ltd | Wholesale & retail | 2025 |
| Biox Limited | Manufacturing | 1984 |
| Birch Meadow (Barkway) Management Company Limited | Households | 2018 |
| Birchanger Hall Farms Limited | Agriculture & fishing | 1996 |
| Birchington Court RTM Company Limited | Households | 2012 |
| Birthlight | Health & social care | 2000 |
| Bishop Development Services Ltd | Construction | 2023 |
| Bishops Court (Trumpington) Limited | Real estate | 2005 |
| Bishops Court (Trumpington) Residents Company Limited | Real estate | 1968 |
| Bison River Limited | Administrative & support | 2000 |
| BIT Technical Solutions Ltd | Professional & scientific | 2025 |
| Bittern Asset Management Ltd | Wholesale & retail | 2021 |
| Black Castle Developments Limited | Real estate | 2006 |
| Black Corvus Ltd | Professional & scientific | 2025 |
| Black Moon Shadow Limited | Professional & scientific | 2019 |
| Black PIG Holdings Limited | Financial services | 2021 |
| Black PIG Limited | Professional & scientific | 1999 |
| Black Widow Holdings Ltd | Financial services | 2026 |
| Blackfusiondev Ltd | Information & communication | 2011 |
| Blacksheep Power Limited | Manufacturing | 2025 |
| Blacksheep Sciences Limited | Manufacturing | 2023 |
| Blaven Studios Ltd | Arts & recreation | 2024 |
| Blenheim Carpet Co. Limited | Wholesale & retail | 1984 |
| Blinds in London Ltd | Wholesale & retail | 2017 |
| Blinds of London Ltd | Wholesale & retail | 2025 |
| Blissful Q Productions Ltd | Information & communication | 2021 |
| Blizzard Blasting Solutions Limited | Administrative & support | 2023 |
| Blockchain Consultants Ltd. | Financial services | 2011 |
| Blooming Natural Ltd | Agriculture & fishing | 2026 |
| Blooper Photobooths Ltd | Professional & scientific | 2012 |
| Blue Diamond Enterprises Limited | Real estate | 2011 |
| Blue JAY Advisory Limited | Professional & scientific | 2018 |
| Blue Orange Brand Management Limited | Wholesale & retail | 1999 |
| Blue Tree EOT Limited | Administrative & support | 2025 |
| Blue Tree Gourmet Gifts Limited | Wholesale & retail | 2015 |
| Blue Tree Limited | Wholesale & retail | 2001 |
| Bluebond Estate Planning Limited | Professional & scientific | 2021 |
| Bluebond Group Limited | Administrative & support | 2006 |
| Bluebond Legal Services Limited | Professional & scientific | 2023 |
| Bluebond Property Tax Limited | Financial services | 2026 |
| Bluebond Tax Planning Ltd | Financial services | 2019 |
| Bluebond Tax Solutions Limited | Professional & scientific | 2021 |
| Bluedeer Technologies Ltd | Information & communication | 2023 |
| Bmcy Ltd | Administrative & support | 2024 |
| Bnet Communications Limited | Information & communication | 2016 |
| Boizie Limited | Wholesale & retail | 2021 |
| Bond Associates Global Limited | Administrative & support | 2023 |
| Bonds Crescent Management Limited | Extraterritorial | 2020 |
| Bondulance Brosenhoe Ltd | Wholesale & retail | 2024 |
| Bongiwe Limited | Health & social care | 2015 |
| Book-Keeping for Rural Businesses Ltd | Professional & scientific | 2012 |
| Boonus Limited | Professional & scientific | 2017 |
| Bornad Building and Cleaning Limited | Construction | 2013 |
| Bosc Childcare Ltd | Health & social care | 2019 |