| Axle Video Limited | Information & communication | 2015 |
| Ayam Pharma Limited | Wholesale & retail | 2017 |
| Aylesbury Automatic Leisure Ltd | Information & communication | 2011 |
| Aylesbury Vale Signs Limited | Real estate | 2025 |
| Aylsham Feathers Ltd | Hospitality | 2019 |
| Ayurvedic Wellness Academy Ltd | Education | 2026 |
| B Pyper Groundwork and Construction Ltd | Construction | 2018 |
| B-17 Ltd | Wholesale & retail | 2026 |
| B-Loony (U.K.) Limited | Extraterritorial | 1984 |
| B-Loony Holdings Limited | Professional & scientific | 2000 |
| B-Loony Limited | Manufacturing | 1978 |
| B-Loony Trustee Limited | Extraterritorial | 2023 |
| B.D.S. Offroad Parts Import & Manufacturing Ltd | Wholesale & retail | 2021 |
| B.E.G. UK Limited | Wholesale & retail | 2004 |
| B.M Property Service Limited | Real estate | 2014 |
| Baan Tomyum Restaurant Ltd | Hospitality | 2023 |
| Back on Road Ltd | Wholesale & retail | 2017 |
| Backstage Bookkeeping and Accounts Ltd | Professional & scientific | 2023 |
| Backup Ltd | Administrative & support | 2025 |
| Baggage Media Ltd | Professional & scientific | 2024 |
| Bains Project Management Limited | Information & communication | 2017 |
| Bains Watts Ltd | Administrative & support | 2008 |
| Bakers Street Limited | Manufacturing | 2019 |
| Baklavalicious UK Ltd | Hospitality | 2020 |
| Balanced Body Pilates Ltd | Wholesale & retail | 2023 |
| Balanced Economy Project | Other services | 2021 |
| Balgley Manufacturing Company Limited | Construction | 1937 |
| Bank Farm RDA Limited | Health & social care | 2011 |
| Bannerman Ventures Ltd | Hospitality | 2016 |
| Baps Hospitality Services Ltd | Professional & scientific | 2023 |
| Barber Maritime Limited | Professional & scientific | 2017 |
| Barclay Taylor Ltd | Professional & scientific | 2007 |
| Barr Studios Ltd | Professional & scientific | 2025 |
| Barracks Lane and Crescent Road (Oxford) Management Company Limited | Households | 2006 |
| Barrett Batstone Properties Limited | Real estate | 2023 |
| Bataa Ltd | Real estate | 2025 |
| Batterbury Limited | Other services | 2013 |
| Battlegearuk Ltd | Wholesale & retail | 2018 |
| Battsco Limited | Administrative & support | 2009 |
| Baytree DST Properties Limited | Real estate | 2016 |
| BCH Surveying & Estimating Services Ltd | Professional & scientific | 2020 |
| BE Here NOW Consultancy Limited | Information & communication | 2024 |
| Beachview Technologies Limited | Information & communication | 2007 |
| Beaumont Art Limited | Financial services | 2012 |
| Beautiful Calm Ltd | Other services | 2020 |
| Bebebombom Limited | Wholesale & retail | 2015 |
| Becaris Publishing Limited | Information & communication | 2022 |
| Beckwith Healthcare Limited | Financial services | 2024 |
| Bedri Ltd | Transport & logistics | 2018 |
| Beech Tree Construction Management Limited | Construction | 2026 |
| Beechfield Contracts Limited | Construction | 2022 |
| Bekan Holdings Limited | Financial services | 2018 |
| Belden Build Ltd | Construction | 2021 |
| Belden Property Ltd | Real estate | 2016 |
| Belenora Ltd | Professional & scientific | 2020 |
| Beliff Limited | Administrative & support | 2016 |
| Bell Street (PR) Management Limited | Real estate | 2015 |
| Bellingdon News Limited | Wholesale & retail | 2025 |
| Bellow Films Limited | Information & communication | 2008 |
| Bellwheel Cottage Productions Limited | Information & communication | 2011 |
| BEN Jeffery Artist Ltd | Arts & recreation | 2024 |
| Berkeley Ambition Limited | Real estate | 2016 |
| Berkeley Asset Management LLP | | 2009 |
| Berkeley Close Chesham Management Company Limited | Households | 1991 |
| Berkeley Lane Ltd | Real estate | 2024 |
| Berks Investment Limited | Real estate | 2022 |
| Berry Farm Film Studios Ltd | Real estate | 2018 |
| Berry Films Ltd | Professional & scientific | 2020 |
| Bertie Green Limited | Wholesale & retail | 2011 |
| Bespoke AV Productions Ltd | Arts & recreation | 2023 |
| Bespoke Care (UK) Limited | Professional & scientific | 2009 |
| Best Floor Fitters Ltd | Construction | 2025 |
| BEST1EXPRESS Limited | Wholesale & retail | 2024 |
| Better Back Office Limited | Professional & scientific | 2024 |
| Better Body Therapy Ltd | Health & social care | 2023 |
| Better Homes for YOU Ltd | Health & social care | 2025 |
| Better Mobility Limited | Health & social care | 2007 |
| Better Spaces Ltd | Construction | 2017 |
| Better Value Wholesale Ltd | Wholesale & retail | 2026 |
| Bevanhill Ltd | Information & communication | 2023 |
| Beyond Estates Limited | Real estate | 2025 |
| Beyond Limits Technologies Ltd | Administrative & support | 2020 |
| BGR Holdings Group Limited | Financial services | 2022 |
| BGR Modular Classrooms Limited | Construction | 2022 |
| Bibi's Beauty & Aesthetics Ltd | Other services | 2017 |
| Big Page Ltd | Information & communication | 2011 |
| Bike Park Chilterns CIC | Arts & recreation | 2019 |
| Biocourt Limited | Professional & scientific | 1994 |
| Bioreproduction Limited | Health & social care | 2010 |
| Birch Bros.Limited | Information & communication | 1971 |
| Birkett Way (Chalfont ST Giles) Management Limited | Real estate | 1998 |
| Bizmaker Limited | Professional & scientific | 2003 |
| BJA Consultancy Services Limited | Professional & scientific | 2023 |
| BKA Fund Consultancy Limited | Professional & scientific | 2013 |
| Black Sky Global Limited | Wholesale & retail | 2015 |
| Blackberet Media Limited | Manufacturing | 2023 |
| Blackberry Cleaning & Support Services Ltd | Administrative & support | 2012 |
| Blackstone Automotive Limited | Wholesale & retail | 2026 |
| Blagden & Daughters Ltd | Real estate | 2022 |
| Bloomsbury Bazaar Ltd | Wholesale & retail | 2011 |