| Bridgewater Lodge Management Company Limited | Households | 2016 |
| Bridgewise Limited | Professional & scientific | 2024 |
| Bridgewood Construction Limited | Construction | 2013 |
| Bridging Gloves | Arts & recreation | 2015 |
| Bright Barley Drinks Ltd | Wholesale & retail | 2020 |
| Bright Choice Marketing LLP | | 2019 |
| Brighter Days Healthcare Ltd | Other services | 2022 |
| Brighter Green Engineering Limited | Manufacturing | 2015 |
| Brightride Group Ltd | Administrative & support | 2025 |
| Brightway Supported Housing CIC | Health & social care | 2025 |
| Brill Edwards Limited | Professional & scientific | 2005 |
| Brilliant Enterprise Solution Ltd | Wholesale & retail | 2025 |
| Brilliant Gateways Consulting & Solutions Ltd | Wholesale & retail | 2024 |
| Brilliant Minds Consulting Solutions Limited | Wholesale & retail | 2025 |
| Bring ME Sunshine Window Cleaning Ltd | Administrative & support | 2023 |
| Britannia Clinical Research Services Ltd | Professional & scientific | 2022 |
| Britco Services Ltd | Administrative & support | 2023 |
| Britian Moving Ltd | Transport & logistics | 2025 |
| Britin Trading Ltd | Wholesale & retail | 2021 |
| British Green Energy Limited | Energy | 2007 |
| British Green Finance Limited | Financial services | 2009 |
| British Green Limited | Information & communication | 2007 |
| British Horse Council CIC | Other services | 2018 |
| British Ukrainian Expertise Ltd | Professional & scientific | 2025 |
| Broadcast RF Limited | Information & communication | 1998 |
| Broadlands(Builders)Limited | Professional & scientific | 1958 |
| Broadpress Limited | Real estate | 2021 |
| Broadway Fields Residents Management Company Limited | Extraterritorial | 2006 |
| Brochure Connect Limited | Professional & scientific | 2005 |
| Brocklehurst Architects Limited | Professional & scientific | 1999 |
| Broddick House (Management) Company Limited | Households | 1976 |
| Brogden Court RTM Company Limited | Households | 2020 |
| Broglad Carpentry and Joinery Ltd | Construction | 2025 |
| Bronze Nation Limited | Information & communication | 2022 |
| Brook Equities Limited | Wholesale & retail | 2025 |
| Brookfield Farm Properties Limited | Real estate | 2018 |
| Brooklands Court Management (High Wycombe) Limited | Professional & scientific | 1994 |
| Brooks Braithwaite Holdings Limited | Financial services | 2011 |
| Brooks Chiropractic Ltd | Health & social care | 2023 |
| Brooks Coach Hire Ltd | Transport & logistics | 2021 |
| Brooks,Braithwaite & Co.Limited | Financial services | 1965 |
| Brookside Flat Management Company Limited | Households | 1988 |
| Brothers Convenience Stores Ltd | Wholesale & retail | 2018 |
| Brothers Logistics & Removals Ltd | Transport & logistics | 2021 |
| Broughton Corner Wines Limited | Wholesale & retail | 2025 |
| Brown Ginger Restaurant Limited | Hospitality | 2022 |
| Brown Pictures Ltd | Professional & scientific | 2021 |
| BRT Products Ltd | Wholesale & retail | 2024 |
| Bruce Solutions Services Ltd | Construction | 2025 |
| Brunswick Design Company Ltd | Professional & scientific | 2020 |
| Bryad Developments Limited | Extraterritorial | 1975 |
| Bryan Woolley Ltd | Construction | 2019 |
| Bryanston Brown Group Ltd | Financial services | 2026 |
| Bryanston Brown Kairos Ltd | Real estate | 2026 |
| Bryant Building & Development Limited | Construction | 1989 |
| Bryant Country Homes Limited | Extraterritorial | 1992 |
| Bryant Group Services Limited | Extraterritorial | 1976 |
| Bryant Homes Central Limited | Extraterritorial | 1954 |
| Bryant Homes East Midlands Limited | Extraterritorial | 1959 |
| Bryant Homes Limited | Extraterritorial | 1987 |
| Bryant Homes North East Limited | Extraterritorial | 1993 |
| Bryant Homes Northern Limited | Extraterritorial | 1990 |
| Bryant Homes South West Limited | Extraterritorial | 1954 |
| Bryant Homes Southern Limited | Extraterritorial | 1938 |
| Bryant Properties Ltd | Construction | 1973 |
| Bryer Law Ltd | Professional & scientific | 2026 |
| Brylaw Limited | Real estate | 2020 |
| BS Auto Services Ltd | Wholesale & retail | 2021 |
| BS Koetz Ltd | Professional & scientific | 2015 |
| Bsake Limited | Real estate | 2014 |
| BSH Express Ltd | Wholesale & retail | 2024 |
| Bssb Logistic Limited | Transport & logistics | 2026 |
| BSU Trading Limited | Manufacturing | 2013 |
| Btlanka Ltd | Administrative & support | 2025 |
| BTM Partnership Limited | Real estate | 2017 |
| BTR Properties Ltd | Real estate | 2024 |
| Btsl Homes Ltd | Real estate | 2023 |
| Buckingham Annexe Ltd | Hospitality | 2023 |
| Buckingham Freehold Ltd | Real estate | 2025 |
| Buckingham Hotel Ltd | Real estate | 2014 |
| Buckingham Hotels Group Limited | Hospitality | 2004 |
| Buckingham Laundry Ltd | Real estate | 2016 |
| Buckingham Legal Associates Ltd | Professional & scientific | 2013 |
| Buckingham NO 1 Limited | Hospitality | 2018 |
| Buckingham NO 2 Limited | Hospitality | 2019 |
| Buckingham NO 3 Ltd | Real estate | 2020 |
| Buckingham Place Developments LLP | | 2006 |
| Buckingham Surveyors Ltd | Professional & scientific | 2020 |
| Buckinghamshire & Berkshire Scaffolding Ltd | Construction | 2020 |
| Buckinghamshire and East Berkshire Mind | Health & social care | 2003 |
| Buckinghamshire Card Show Limited | Administrative & support | 2026 |
| Buckinghamshire Education Skills and Training | Education | 2013 |
| Buckinghamshire Electrical Limited | Energy | 2017 |
| Buckinghamshire Foods Ltd | Wholesale & retail | 2025 |
| Buckinghamshire Heating Limited | Construction | 2006 |
| Buckinghamshire Maintenance Ltd | Extraterritorial | 2019 |
| Buckinghamshire Plumbing Ltd | Construction | 2017 |
| Buckinghamshire Scaffolding Ltd | Construction | 2015 |
| Buckinghamshire Services 2020 Limited | Extraterritorial | 2013 |
| Buckinghamshire Therapies Limited | Administrative & support | 2022 |