| B9 Estates Ltd | Real estate | 2022 |
| Badger Gardens 37 Ltd | Real estate | 2025 |
| Bainsfair Transport Ltd | Transport & logistics | 2024 |
| Bakers Yard (Pangbourne) Limited | Households | 2016 |
| Balbinka Grocery Ltd | Wholesale & retail | 2025 |
| Balbinka Ltd | Wholesale & retail | 2017 |
| Baldasera's Ltd | Hospitality | 2011 |
| Balfa UK Limited | Wholesale & retail | 2004 |
| Balmarc Ltd | Hospitality | 2019 |
| Baptist House Limited | Other services | 1989 |
| Baptist Missionary Society Corporation,(The) | Other services | 1888 |
| Baptist Missionary Society Pension Trust Limited | Financial services | 1997 |
| Baptist Missionary Trading Company Limited | Wholesale & retail | 1991 |
| Baptist Pension Trust Limited | Financial services | 1997 |
| Baptist Union Corporation Limited(The) | Other services | 1890 |
| Bareham Wealth Limited | Real estate | 2024 |
| Barking Bowser Doggy Daycare Limited | Other services | 2025 |
| Barn END Events Ltd | Arts & recreation | 2014 |
| Baybe.Org Limited | Hospitality | 2000 |
| Bayoluone Investments Ltd | Wholesale & retail | 2025 |
| Baytihomes Ltd | Real estate | 2025 |
| Bayulgen Ltd | Real estate | 2026 |
| BB Health Solutions Ltd | Professional & scientific | 2015 |
| BD X Ltd | Information & communication | 2025 |
| BE Free Young Carers | Other services | 1994 |
| Bears-Brew Limited | Hospitality | 2025 |
| Beaulea Clinic Ltd | Health & social care | 2024 |
| Beautiful Game Media Limited | Arts & recreation | 2005 |
| Beauty Essentials Limited | Health & social care | 2015 |
| Beauty Within Didcot Ltd | Other services | 2022 |
| Beauty Within Online Ltd | Wholesale & retail | 2018 |
| Beauty Within Salon Ltd | Other services | 2017 |
| Becloudify Consulting Ltd | Information & communication | 2020 |
| Beco Compliance Limited | Public administration | 2021 |
| Beecham Property Ltd | Real estate | 2022 |
| Bees & Goose Brewing Co Limited | Manufacturing | 2020 |
| BEI Electrical and Construction Ltd | Construction | 2015 |
| Bell-Thomas Ltd | Financial services | 2025 |
| Bella C R P Ltd | Real estate | 2025 |
| Bella Haycraft MEE Ltd | Hospitality | 2023 |
| Bella Spice Limited | Hospitality | 2024 |
| Bellewood Homes Limited | Construction | 2024 |
| Benfin Consulting Ltd | Information & communication | 2025 |
| Bengal House Spice Ltd | Hospitality | 2025 |
| Benguela Events Limited | Professional & scientific | 2008 |
| Benignoara Limited | Health & social care | 2022 |
| Berry ABI Investments Limited | Real estate | 2025 |
| Best Autocentres Ltd | Wholesale & retail | 2003 |
| Betsy Crafts Ltd | Manufacturing | 2024 |
| Betty Bloom Dance Limited | Arts & recreation | 2015 |
| BFT Associates Ltd | Real estate | 2020 |
| Biha Ltd | Real estate | 2026 |
| Bikini Bible Ltd | Wholesale & retail | 2020 |
| Bimension Ltd | Information & communication | 2026 |
| Bio-Prodigy Ltd | Real estate | 2024 |
| Biouk Ltd | Other services | 2026 |
| Birkett Property Estates Ltd | Real estate | 2024 |
| Bizwarez Ltd | Professional & scientific | 2017 |
| Black Book Executive Search Limited | Administrative & support | 2005 |
| Black Onyx Events Ltd | Professional & scientific | 2018 |
| Blackbee Sound Ltd | Information & communication | 2010 |
| Blackworks Ltd | Wholesale & retail | 2021 |
| Blackworks Property Ltd | Real estate | 2025 |
| Blanco Bags Limited | Manufacturing | 2021 |
| Blewbury Botox Solutions Limited | Other services | 2025 |
| Blewbury Properties Limited | Real estate | 2025 |
| Blewbury Road Orchard Ltd | Extraterritorial | 2021 |
| Blewpri Ltd | Information & communication | 2012 |
| Blink Projects Ltd | Professional & scientific | 2015 |
| Blue Bamboo Design Limited | Professional & scientific | 2015 |
| Blue Beryl Ltd | Professional & scientific | 2017 |
| Blue Boar Homes Ltd | Real estate | 2025 |
| Blue Shake Ltd | Information & communication | 2021 |
| Bluefruit Video Ltd | Information & communication | 2012 |
| Bluestones Training Ltd | Professional & scientific | 2020 |
| Bodyfit Therapies Ltd | Health & social care | 2017 |
| Bookkeeps Services Ltd | Professional & scientific | 2018 |
| Boswells Coffee Company Limited | Hospitality | 1972 |
| Boswells Group Limited | Financial services | 2024 |
| Bounce Ready Ltd | Administrative & support | 2025 |
| Boundary Park (GWP) Limited | Hospitality | 2016 |
| Bourlon Wood Residents Association Limited | Administrative & support | 1993 |
| Bova Properties Ltd | Real estate | 2025 |
| Bracken and Stone Ltd | Real estate | 2025 |
| Bradcob Ltd | Wholesale & retail | 2021 |
| Bragg Links Ltd | Real estate | 2026 |
| Bramhill Design Ltd | Professional & scientific | 2008 |
| Brant Auto Ltd | Wholesale & retail | 2025 |
| Brent Upston Scaffolding Ltd | Construction | 2024 |
| Brian Mcnamee & Associates Ltd | Professional & scientific | 2010 |
| Briarswood Property Ltd | Real estate | 2017 |
| Bridge Master Medical Limited | Administrative & support | 2008 |
| Bright and Early Limited | Professional & scientific | 2016 |
| Brilliant Basics Consultancy Limited | Professional & scientific | 2011 |
| Bristen Ltd | Professional & scientific | 2017 |
| Britannia Polychem Ltd | Wholesale & retail | 2021 |
| Broad Oak Books Limited | Information & communication | 2020 |
| Broad Oak Partners Limited | Professional & scientific | 2013 |
| Broomsticks Limited | Administrative & support | 2020 |
| Build & Bloom Ltd | Administrative & support | 2024 |