| Broomhill Properties Ltd | Real estate | 1998 |
| Brooms Gardens Limited | Administrative & support | 2024 |
| Brosnaich Ventures Limited | Professional & scientific | 2015 |
| Brothers Food Truck Ltd | Hospitality | 2025 |
| Brothers-In-Food Ltd | Hospitality | 2022 |
| Brown and Sons Services Ltd | Transport & logistics | 2026 |
| Brown Bear Investment Ltd | Real estate | 2023 |
| Brown Bred Pigs Limited | Agriculture & fishing | 1980 |
| Brown Consulting Services Limited | Professional & scientific | 1989 |
| Brownlie & Sons Limited | Hospitality | 2015 |
| Browns Lane Fairfax Limited | Construction | 2022 |
| Brown’S Exterior Clean Ltd | Administrative & support | 2024 |
| Bruder Construction Ltd | Construction | 2025 |
| Brunel Gardens (Maidenhead) Management Company Limited | Households | 2013 |
| Brunswick Hill Management Company Limited | Households | 1978 |
| Brunswick Hill Tenants Association Limited | Households | 1963 |
| Brunswick IP Limited | Professional & scientific | 2013 |
| BSK DW Holdings Limited | Arts & recreation | 2020 |
| BSL Bible Translation Project | Information & communication | 2007 |
| Bsparks Limited | Real estate | 2021 |
| Bssh Limited | Hospitality | 2019 |
| BST Aviation Services Ltd | Manufacturing | 2024 |
| BT Asset Holdings Limited | Real estate | 2025 |
| BTE Skenesom Limited | Financial services | 2025 |
| BTF Asset Holdings Limited | Real estate | 2023 |
| BTL Asset Holdings Limited | Real estate | 2022 |
| BTM Drinks Ltd | Other services | 2020 |
| BTP Pharmaceutical Co., Limited | Wholesale & retail | 2026 |
| Btrc Ltd | Information & communication | 2025 |
| BTT Consulting Ltd | Professional & scientific | 2022 |
| Btvrares Ltd | Manufacturing | 2026 |
| Btxx Ltd | Financial services | 2025 |
| Bubble and Bounce Swim Ltd | Education | 2023 |
| Bubble BOY Film Limited | Arts & recreation | 2024 |
| Bubble Pete Ltd | Wholesale & retail | 2025 |
| Bubble POP (Cambridge) Ltd | Wholesale & retail | 2025 |
| Bubblypropertysolutions Ltd | Real estate | 2018 |
| Buben Limited | Transport & logistics | 2024 |
| Bubi@Srl Ltd | Manufacturing | 2024 |
| Buckingham & Stanley Limited | Wholesale & retail | 1973 |
| Bucko Enterprises Ltd | Information & communication | 2020 |
| Budapest River Cruise Ltd. | Wholesale & retail | 2016 |
| Buddicom Properties Limited | Real estate | 2011 |
| Budding Minds Psychology Ltd | Education | 2025 |
| Buddy Marine Ltd | Manufacturing | 2024 |
| Budworth Development Limited | Construction | 2014 |
| Build Munos Limited | Financial services | 2016 |
| Build Your Home Ltd | Construction | 2025 |
| Builder Cambridge Ltd | Construction | 2019 |
| Building Maintenance Services (Cambridge) Ltd | Construction | 2011 |
| Building Team Limited | Wholesale & retail | 1995 |
| Buildingsmart International Limited | Other services | 2004 |
| Built by Many Ltd | Information & communication | 2018 |
| BUK Solutions Limited | Administrative & support | 1988 |
| Bukhsh Company Limited | Health & social care | 2013 |
| Bulai Vladut Ltd | Manufacturing | 2024 |
| Bulgarian Cultural and Educational SOC. ST. Ivan Rilski CIC | Education | 2014 |
| Bulgin Limited | Manufacturing | 2003 |
| Bulldog Publishing Limited | Information & communication | 1995 |
| Bullman Grove Girton Cambridge Limited | Extraterritorial | 2012 |
| Bumblebee International Ltd | Wholesale & retail | 2024 |
| Bumtotecă.Srl Ltd | Public administration | 2019 |
| Bungle Composites Ltd | Manufacturing | 2016 |
| Buns of Anarchy Ltd | Hospitality | 2025 |
| Bunten Holdings Ltd | Financial services | 2016 |
| Bunting Investments Ltd | Real estate | 2024 |
| Buraq Taxis Ltd | Transport & logistics | 2023 |
| Burbeck Group Limited | Households | 2018 |
| Burbeck Interiors Limited | Wholesale & retail | 2015 |
| Burbeck Project Management Ltd | Construction | 2017 |
| Burchill & Co Ltd | Professional & scientific | 2016 |
| Bureau Health Ltd | Health & social care | 2021 |
| Burebista 2000 Ltd | Manufacturing | 2025 |
| Buren Limited | Hospitality | 2021 |
| Burford Consult Ltd | Professional & scientific | 2024 |
| Burger Newmarket Ltd | Hospitality | 2024 |
| Burgerboys Willingham Limited | Hospitality | 2025 |
| Burgess Forestry Ltd | Agriculture & fishing | 2018 |
| Burghley Property Limited | Real estate | 2026 |
| Burhan Ullah Ltd | Wholesale & retail | 2025 |
| Burleigh Dodds Science Publishing Limited | Information & communication | 2015 |
| Burley Hydraulics (Cambridgeshire) Limited | Manufacturing | 2003 |
| Burling Brothers Limited | Agriculture & fishing | 1964 |
| Burnside Dental Surgery Limited | Health & social care | 2017 |
| Burnt Orange Studios Ltd | Professional & scientific | 2025 |
| Buro Aeberhard Ltd | Professional & scientific | 2024 |
| Burr ELM Limited | Construction | 2001 |
| Burrito Brothers Limited | Wholesale & retail | 2025 |
| Burrowfoot Limited | Information & communication | 2019 |
| Bursali Group Ltd | Manufacturing | 2024 |
| Burwash Manor LLP | | 2022 |
| Burwell & Exning Cricket Club Limited | Arts & recreation | 2016 |
| Burwell Brewery Ltd | Wholesale & retail | 2016 |
| Burwell Community Print Centre Limited | Manufacturing | 1996 |
| Burwell Curry House Ltd | Hospitality | 2022 |
| Burwell Fishing Lake Ltd | Professional & scientific | 2009 |
| Burwell Padel Ltd | Arts & recreation | 2025 |
| Bury Investments LLP | | 2005 |
| Bury ST Edmunds Residential Management Company Limited | Real estate | 2009 |
| Busby Consultants Limited | Professional & scientific | 1997 |