| Blacketts Edge Freehold Limited | Households | 2024 |
| Blackroot Productions Ltd | Information & communication | 2021 |
| Blackwood Property Services Limited | Real estate | 2004 |
| Blanc Aesthetics Academy Ltd | Education | 2022 |
| Blanco Beauty Ltd | Other services | 2023 |
| Bloomfield Webster Consultants Ltd | Professional & scientific | 2017 |
| Blossom Care & Nanny Ltd | Health & social care | 2024 |
| Blue Bell Drycleaners Ltd | Other services | 2021 |
| Blue Sky Gardening Ltd | Administrative & support | 2020 |
| Blue Space Property Seven Limited | Professional & scientific | 2004 |
| Blue Space Property Three Limited | Professional & scientific | 2004 |
| Bluebottle Associates Limited | Information & communication | 2000 |
| Bluestreak Crystals Ltd | Wholesale & retail | 2015 |
| Bluezone Advisory Limited | Professional & scientific | 2025 |
| Blunt One Ltd | Professional & scientific | 2022 |
| Blygold (UK) Limited | Administrative & support | 2001 |
| BM Physio Ltd | Health & social care | 2014 |
| BMH Associates Limited | Professional & scientific | 2013 |
| BNF Assets Ltd | Real estate | 2020 |
| BNF Consultants Ltd. | Professional & scientific | 2017 |
| BNF Storage Ltd | Transport & logistics | 2024 |
| BNS Consulting Services Ltd | Professional & scientific | 2021 |
| BOB Berry Architect Ltd | Professional & scientific | 2015 |
| Boiler Buddies Limited | Construction | 2003 |
| Boilerguard (UK) Ltd | Manufacturing | 2014 |
| Bois Avenue Spinney Limited | Households | 2023 |
| Boldcom Ltd | Wholesale & retail | 2026 |
| Boldcombe Limited | Information & communication | 1981 |
| Bolster Construction Limited | Construction | 2004 |
| Bonzerai Limited | Information & communication | 2023 |
| Boom Marketing & Partnerships Limited | Professional & scientific | 2016 |
| Boom Refurbs & Developments Limited | Construction | 2022 |
| Boost Life Skills Ltd | Education | 2019 |
| Boot Technologies Ltd | Manufacturing | 2015 |
| Bordessa Cooling Ltd | Construction | 2018 |
| Both Huge 2.0 Ltd | Hospitality | 2022 |
| Bourne Entertainment Ltd | Professional & scientific | 2017 |
| Boyle Landscaping Limited | Administrative & support | 2024 |
| BPK Investments Limited | Real estate | 2020 |
| BR Consulting Services Ltd | Professional & scientific | 2020 |
| BR Patel Properties Limited | Real estate | 2026 |
| Brains Matter Limited | Professional & scientific | 2009 |
| Brainwaves Consulting Ltd | Professional & scientific | 2024 |
| Brand Addicts Limited | Administrative & support | 2007 |
| Brandable & Co. Limited | Professional & scientific | 2008 |
| Branmor H0LDINGS Limited | Administrative & support | 2010 |
| Brays Close Management Company Limited | Real estate | 2022 |
| Bricks on Wall Limited | Real estate | 2024 |
| Bridge Consulting Ltd | Professional & scientific | 2020 |
| Bridge Inn PUB Ltd | Hospitality | 2024 |
| Bridger Smart & Co. Ltd | Professional & scientific | 2012 |
| Bright Terra Ltd | Administrative & support | 2024 |
| Brightbrook Ltd | Manufacturing | 2009 |
| Brightside Cottage Limited | Hospitality | 2023 |
| Brightsource Recruitment Limited | Administrative & support | 2014 |
| Briller Holdings Ltd | Financial services | 2021 |
| Bristol Talent Pool Limited | Professional & scientific | 2015 |
| Britechat Ltd | Information & communication | 2014 |
| BRK Legal Consultants Limited | Professional & scientific | 2024 |
| Broadlands Consultants Ltd | Professional & scientific | 2019 |
| Broker Accounts Services Limited | Financial services | 2020 |
| Brokerr UK Ltd | Professional & scientific | 2024 |
| Brolamgest Limited | Construction | 2015 |
| Brooklea Lane Limited | Households | 2017 |
| BSR Investments Ltd | Real estate | 2020 |
| Buckinghamshire Healthcare Charity | Professional & scientific | 2025 |
| Buckinghamshire Healthcare Projects Limited | Health & social care | 2017 |
| Buckinghamshire Rugby Referees Limited | Arts & recreation | 2018 |
| Buckle Building Limited | Real estate | 1986 |
| Bucks Decorating Ltd | Construction | 2015 |
| Bucks Electrical Supplies Ltd | Wholesale & retail | 2024 |
| Bucks Foot Clinic Ltd | Health & social care | 2017 |
| Bucks Legal Group Limited | Professional & scientific | 2025 |
| Buenos Capricorn Ltd | Hospitality | 2020 |
| Build Create Ltd | Construction | 2022 |
| Building BEE Limited | Real estate | 2020 |
| Buildsmart Services Ltd | Construction | 2015 |
| Bull and Banks Ltd | Construction | 2021 |
| Burgermia Ltd | Hospitality | 2026 |
| Bury Farm (Management) Limited | Administrative & support | 1997 |
| Bury Lodge Banqueting Limited | Hospitality | 2010 |
| Bury Lodge Investments Limited | Hospitality | 1994 |
| Business and Trade Statistics Limited | Professional & scientific | 2023 |
| Business Personified Limited | Administrative & support | 2024 |
| Buy Side Recruitment Ltd. | Administrative & support | 2014 |
| Buzz Brilliance Services Limited | Wholesale & retail | 2024 |
| Bvrla Services Limited | Other services | 2005 |
| BW Trustees (Cheltenham) Limited | Financial services | 1990 |
| C & J Gardening and Landscaping Ltd | Administrative & support | 2024 |
| C.C.S. (Catercare) Limited | Manufacturing | 1995 |
| CA Carwash Ltd | Administrative & support | 2024 |
| Cafe Africa LLP | | 2008 |
| Calfpress Ltd | Manufacturing | 2023 |
| Callisto UT Services Ltd | Information & communication | 2024 |
| Calvert Jones Limited | Professional & scientific | 2012 |
| CAM OT Services Limited | Health & social care | 2011 |
| Camberwell Green DIY Ltd | Wholesale & retail | 2025 |
| Cambridge Data Insights Limited | Professional & scientific | 2019 |
| Cambrook Productions Ltd | Information & communication | 2023 |
| Camellia Consultancy Group Ltd | Real estate | 2024 |