| Baxters Tractors Ltd | Manufacturing | 2025 |
| Bay Bright Properties Ltd | Real estate | 2021 |
| Bayard Plaza Limited | Real estate | 2018 |
| Bayard Plaza Management Limited | Professional & scientific | 2019 |
| Bazro Limited | Wholesale & retail | 2024 |
| BB Advisory Services Limited | Professional & scientific | 2017 |
| BB Bookkeeping Ltd | Professional & scientific | 2023 |
| BC Services PHE Ltd | Administrative & support | 2011 |
| BCD Coaching Ltd | Other services | 2022 |
| Beachpads Limited | Hospitality | 2011 |
| Beaconwold Holdings Ltd | Professional & scientific | 2025 |
| Bearface Consultancy Ltd | Information & communication | 2010 |
| Beautiful One Limited | Other services | 2015 |
| Beauty Crewe Ltd | Other services | 2017 |
| Bedford Road Car Park Ltd | Administrative & support | 2001 |
| Belgravia S P V Ltd | Real estate | 2024 |
| Belles Bars Limited | Hospitality | 2025 |
| Belmont Holdings Trading Group Limited | Financial services | 2025 |
| Belmont Laundry Aldershot Limited | Administrative & support | 1998 |
| Belmont Laundry Limited | Other services | 1986 |
| Benandan Limousines Ltd | Other services | 2014 |
| Benchmark Electrical Limited | Construction | 2010 |
| Bengal Spice Express Limited | Hospitality | 2024 |
| Bengal ST Ives Limited | Hospitality | 2024 |
| Bengoor Limited | Professional & scientific | 2021 |
| Bensten Motors Limited | Wholesale & retail | 2006 |
| Benwick Sports Limited | Wholesale & retail | 2014 |
| Bernard Leach Enterprises Limited | Manufacturing | 2006 |
| Berts Bread and Meat Ltd | Hospitality | 2026 |
| Bicester Purchasing Services Ltd | Administrative & support | 2009 |
| Bigglesworth Investments Limited | Real estate | 2006 |
| Billton Motors Limited | Wholesale & retail | 2020 |
| Biometric Solutions Limited | Professional & scientific | 1997 |
| Birch Branch Ltd | Real estate | 2024 |
| BJN 2016 Limited | Construction | 2016 |
| BK Rowlands Ltd | Health & social care | 2025 |
| Black Eyed Jack Ltd | Hospitality | 2017 |
| Black Halo Global Ltd | Administrative & support | 2025 |
| Black Robin Coffee Limited | Wholesale & retail | 2018 |
| BLACKCOW25 Limited | Wholesale & retail | 2025 |
| Blesstree Limited | Real estate | 1981 |
| Blewbury Digital Acceleration Ltd | Information & communication | 2020 |
| Blink Ace Reporting Limited | Information & communication | 2013 |
| Blou MOR Ltd | Construction | 2018 |
| Blue Bay Car Hire Ltd | Administrative & support | 2025 |
| Blue Cipher Ltd | Information & communication | 2026 |
| Blue Circle Consulting Ltd | Information & communication | 2025 |
| Blue Cove Properties Ltd | Real estate | 2026 |
| Blue Planet (Group) Limited | Financial services | 2014 |
| Blue Shark Snorkel Ltd | Arts & recreation | 2023 |
| Blue Thunder RIB Rides Ltd | Transport & logistics | 2019 |
| Bluebird Real Estate Ltd | Real estate | 2022 |
| Bluecrow Shopfitting Ltd | Construction | 2020 |
| Bluecrow Team Ltd | Manufacturing | 2021 |
| Blueproof Ltd | Information & communication | 2025 |
| Blumehound Ltd | Real estate | 2024 |
| Boat Trips ST Ives Ltd | Administrative & support | 2022 |
| Bodhi Tree Investments Ltd | Real estate | 2025 |
| Bolitho Nursery Limited | Education | 2016 |
| Bond Construction Limited | Construction | 2021 |
| Bonorbis Limited | Manufacturing | 2017 |
| Booking Properties Ltd | Real estate | 2023 |
| Boormans (Carbis Water) Limited | Extraterritorial | 2006 |
| Bopxi Cars Limited | Transport & logistics | 2025 |
| Born in Summer Limited | Real estate | 2024 |
| Bornio Ltd | Real estate | 2024 |
| Bost Group Ltd | Financial services | 2024 |
| BOX3 Motorsport Ltd | Arts & recreation | 2024 |
| Boyd Investments Limited | Real estate | 1963 |
| BPF Properties Ltd | Administrative & support | 2015 |
| Brand Inc Clothing Ltd | Wholesale & retail | 2023 |
| Brand Inc Collective Ltd | Real estate | 2021 |
| Brand Inc. Creative Ltd | Professional & scientific | 2018 |
| Brand Inc. Fitness Ltd | Administrative & support | 2017 |
| Brandon Car Centre Limited | Wholesale & retail | 2007 |
| Brandxchange.Agency Ltd | Professional & scientific | 2022 |
| Brickwork Contracting Limited | Construction | 2010 |
| Bridge House Residents Association (1997) Company Limited | Real estate | 1998 |
| Bridge Integrated Security Ltd | Administrative & support | 2021 |
| Bright Architectural Solutions Ltd | Professional & scientific | 2021 |
| Bright Bridge Learning Ltd | Administrative & support | 2025 |
| Bright Buildings Ltd | Real estate | 2021 |
| Brightfield Bushfield Limited | Construction | 2016 |
| Brightfield Crowland Developers Limited | Hospitality | 2018 |
| Brightfield Crowland Limited | Construction | 2017 |
| Brightfield Group Holdings Ltd | Real estate | 2021 |
| Brightfield Group Limited | Households | 2018 |
| Brightfield Healthcare Ltd | Real estate | 2021 |
| Brightfield Innovation Limited | Real estate | 2012 |
| Brightfield Laxton Limited | Construction | 2019 |
| Brightfield Papworth Limited | Construction | 2020 |
| Brightfield Plaza Limited | Wholesale & retail | 2020 |
| Brightfield Stafford Limited | Real estate | 2016 |
| Brightfield Towngate Limited | Real estate | 2014 |
| Brightotel Limited | Hospitality | 2020 |
| Brightstone Ltd | Financial services | 2022 |
| Brine St.Ives Ltd | Hospitality | 2025 |
| Brisk Solutions Limited | Information & communication | 2013 |
| Bristowe IP Holdings Ltd | Information & communication | 2026 |
| Britaven Limited | Construction | 1990 |