| B. & S. Glass Industries Ltd. | Manufacturing | 1928 |
| B.T.A. Property Services Ltd | Real estate | 2023 |
| Baby Jack Armoury Limited | Arts & recreation | 2026 |
| Back Office Projects Limited | Professional & scientific | 2009 |
| Back on Track Motorsport Limited | Wholesale & retail | 2014 |
| Backbeat Properties Ltd | Real estate | 2022 |
| Baddabing Ltd | Professional & scientific | 2021 |
| Bailey Lane Property Ltd | Real estate | 2025 |
| Baileygomm Design Limited | Professional & scientific | 2018 |
| Baileygomm Group Limited | Financial services | 2018 |
| Bake. Group Ltd | Other services | 2024 |
| Balance IT Limited | Information & communication | 2022 |
| Bali Construction Group Ltd. | Real estate | 2019 |
| Bamboo Said the Bear Ltd | Wholesale & retail | 2020 |
| Banton's Buttons Ltd | Manufacturing | 2018 |
| Banu Rose Ltd | Manufacturing | 2017 |
| Barion Limited | Professional & scientific | 2005 |
| Baris&Alaz Ltd | Hospitality | 2024 |
| Barleyhill Services Limited | Professional & scientific | 2008 |
| Barn Door UK Limited | Professional & scientific | 2015 |
| Barnaby Adler Ltd | Wholesale & retail | 2025 |
| Barrydene Court Residents Association Limited | Households | 1981 |
| Barry’S Buses Ltd | Transport & logistics | 2023 |
| Barwood Lock and Door Services Limited | Manufacturing | 2015 |
| Bayford Lofts Ltd | Construction | 2020 |
| Bayhouse Holding Co | Financial services | 2022 |
| BE Free Forest School Ltd | Education | 2018 |
| BE Free Homes Limited | Real estate | 2024 |
| BE Free Ltd | Other services | 2009 |
| BE the Storm Limited | Education | 2021 |
| Beach Plumbing and Heating Buntingford Limited | Construction | 2019 |
| Beaconsfield Road Management Limited | Households | 1992 |
| Beanstalk Music Limited | Arts & recreation | 2019 |
| Beanstalk Properties Limited | Real estate | 2024 |
| Beardy Hospitality Ltd | Hospitality | 2025 |
| Beaton Lift Installations Limited | Construction | 2023 |
| Beaumax Flooring Ltd | Construction | 2021 |
| Beauty Boxes Ltd | Other services | 2022 |
| Bella Party Accessories Ltd | Other services | 2018 |
| Beneficial Clothing Limited | Wholesale & retail | 2024 |
| Berestock Limited | Arts & recreation | 1986 |
| Best of Both Worlds Limited | Administrative & support | 2000 |
| Best Sports Fitness Wear Ltd | Wholesale & retail | 2022 |
| Better BEE Transport and Removals Ltd | Transport & logistics | 2025 |
| Better Sporting Ltd | Wholesale & retail | 2020 |
| Betts Official Ltd | Manufacturing | 2025 |
| Betty Bostock Consulting Ltd | Administrative & support | 2018 |
| Between Time Limited | Construction | 2002 |
| Beverley Hills Interiors Limited | Manufacturing | 1994 |
| Beverley Hills Investments Limited | Real estate | 2012 |
| Beyond Governance Investments Limited | Financial services | 2022 |
| Beyond Governance Ltd | Professional & scientific | 2019 |
| Beyond Governance Secretarial Services Limited | Extraterritorial | 2026 |
| Beyond Governance Services Limited | Professional & scientific | 2024 |
| Beyond the Game Recruitment Ltd | Administrative & support | 2025 |
| Bibiana Ltd | Wholesale & retail | 2025 |
| Bidwell Ventures UK Ltd | Construction | 2024 |
| Big Ocean Ventures Limited | Extraterritorial | 2022 |
| Big Print Little Print Ltd | Wholesale & retail | 2019 |
| Billderpay Technologies Ltd | Information & communication | 2025 |
| Billderpay Trustee Ltd | Financial services | 2025 |
| Billie Waters Consulting Ltd | Professional & scientific | 2025 |
| Bioprocess Ltd | Manufacturing | 2022 |
| BIT Solutions Limited | Information & communication | 2008 |
| Black Grove Farm Ltd | Agriculture & fishing | 2018 |
| Black Grove Greens CIC | Agriculture & fishing | 2018 |
| Blackdg Group Limited | Professional & scientific | 2024 |
| Blackfen Associates Limited | Administrative & support | 2012 |
| Blackhedge Holdings Limited | Financial services | 2017 |
| Bladenwood Farm Limited | Real estate | 2024 |
| Blend Organics Ltd | Hospitality | 2022 |
| Blend Wellness Ltd | Hospitality | 2024 |
| Blinky Ltd | Information & communication | 2016 |
| Blue Oak Services Limited | Administrative & support | 2020 |
| Bluefriar Properties Limited | Real estate | 2005 |
| Blyth Property Limited | Real estate | 2016 |
| BM Sound and Entertainment Ltd | Other services | 2019 |
| BNH Cleaning Ltd | Administrative & support | 2025 |
| BOB O JOB Ltd | Administrative & support | 2026 |
| Bobtails Playgroup & Teddy Club | Education | 2010 |
| Boiler Boffin Ltd | Construction | 2017 |
| Bold Letters Ltd | Professional & scientific | 2018 |
| Bonnie Dolls Ragdolls Ltd | Agriculture & fishing | 2025 |
| Book Nook Ltd | Wholesale & retail | 2018 |
| Bourne Store Ltd | Wholesale & retail | 2026 |
| Bournes Projects Limited | Construction | 2013 |
| Bowling Construction Limited | Construction | 2012 |
| Bows Soccer Buckinghamshire Ltd | Education | 2026 |
| Bows Soccer Limited | Education | 2017 |
| Bowsher Co Ltd | Administrative & support | 2026 |
| Boxed-Delights Ltd | Wholesale & retail | 2026 |
| Bradley Services Ltd | Construction | 2023 |
| Breading and Coating Holdings Ltd | Professional & scientific | 2014 |
| Breading and Coating Ltd | Manufacturing | 2012 |
| Breakfast Agency Limited | Professional & scientific | 2009 |
| Brial X Ltd | Transport & logistics | 2016 |
| Brick-Tech Construction Ltd | Construction | 2018 |
| Brickfields Management Company (Ware) Limited | Other services | 1992 |
| Bricon Limited | Construction | 2015 |
| Bridgeman Landscaping Limited | Professional & scientific | 1997 |