| Barker's Yard Management Company Limited | Households | 2007 |
| Barkway House Estates Limited | Financial services | 2021 |
| Barley Cottage Ltd | Real estate | 2024 |
| Barley Grange (Oundle Road) Management Company Limited | Households | 2004 |
| Barley Loft Properties Ltd | Real estate | 2022 |
| Barleycorn Apartment Ltd | Real estate | 2020 |
| Barmac Services Limited | Administrative & support | 2017 |
| Barmoore Limited | Real estate | 1986 |
| Barn Close Storage Limited | Transport & logistics | 2009 |
| Barnabar Limited | Real estate | 2017 |
| Barnaby Productions Limited | Information & communication | 2018 |
| Barnacle Capital Ltd | Financial services | 2022 |
| Barnes & Maney Limited | Wholesale & retail | 1975 |
| Barnes and Barnes Limited | Construction | 2017 |
| Barnes Machinery Co., Ltd | Manufacturing | 2023 |
| Barnett Construction Services Eastern Ltd | Construction | 2012 |
| Barnwell Barbers Ltd | Other services | 2010 |
| Barnwell Florists Limited | Wholesale & retail | 2022 |
| Barnwell Kebabs Ltd | Hospitality | 2024 |
| Barnwell RD HCW Ltd | Other services | 2016 |
| Baroarch Design LAB Ltd | Professional & scientific | 2020 |
| Barocal Ltd | Professional & scientific | 2019 |
| Baroff. Ltd | Wholesale & retail | 2025 |
| Baron UK Properties Ltd | Real estate | 2024 |
| Barr Ellison Legal Limited | Professional & scientific | 2014 |
| Barr Ellison Trust Corporation Limited | Administrative & support | 2014 |
| Barr-Tech Specialist Cars Limited | Wholesale & retail | 2007 |
| Barrack Lane Management Company Limited | Real estate | 2019 |
| Barresi Lettings Limited | Real estate | 2019 |
| Barreto & Barreto Limited | Hospitality | 2015 |
| Barrett Developments Ltd | Real estate | 2024 |
| Barron London Limited | Wholesale & retail | 2016 |
| Barrow Pearl Limited | Construction | 2024 |
| Barry Crabtree-Taylor Limited | Other services | 2020 |
| Barry Douglas Limited | Arts & recreation | 2011 |
| Barry's Service Centre Limited | Wholesale & retail | 2003 |
| Bart Super Garage Ltd | Wholesale & retail | 2023 |
| Bartek Spychalski Limited | Administrative & support | 2017 |
| Bartlomiej Trans Ltd | Transport & logistics | 2015 |
| Bartlow Barns Management Limited | Households | 1998 |
| Barton Elmore Limited | Transport & logistics | 2019 |
| Barton Lily | Financial services | 2023 |
| Barton OIL Burner Services Limited | Manufacturing | 2017 |
| Bartosz Zyla Services Ltd | Transport & logistics | 2023 |
| Basalt Homes Ltd | Real estate | 2026 |
| Basck Invest Limited | Professional & scientific | 2016 |
| Basck Limited | Professional & scientific | 2010 |
| Base Camp Marketing Ltd | Professional & scientific | 2021 |
| Baselets Ltd | Real estate | 2006 |
| Baserange International Holding Group Co., Ltd | Extraterritorial | 2020 |
| Basford Mill (Management) Limited | Households | 2006 |
| Basic Element Brewing Limited | Manufacturing | 2026 |
| Basick Holdings Ltd | Real estate | 2022 |
| Bassem Services Limited | Transport & logistics | 2012 |
| Bastelia Co. Ltd | Wholesale & retail | 2020 |
| Bastion Meadery Ltd | Manufacturing | 2026 |
| BAT Scaffold Ltd | Construction | 2025 |
| Bateman Estates Limited | Real estate | 2023 |
| Battenberg Service Limited | Other services | 2023 |
| Bauer Fitness Ltd | Education | 2024 |
| Baufritz (UK) Ltd. | Construction | 2006 |
| Bauhinia Software Ltd | Information & communication | 2019 |
| Bay Beyond Limited | Wholesale & retail | 2025 |
| Bay Commerce Limited | Wholesale & retail | 2026 |
| Bayard Construction Ltd | Construction | 2011 |
| Baycamb Limited | Professional & scientific | 2015 |
| Bayfield Training Limited | Information & communication | 1999 |
| Bayin Sarl Limited | Wholesale & retail | 2021 |
| Baythorne Homes Ltd | Real estate | 2017 |
| Baywill Property Management Limited | Households | 2003 |
| Bazpat Properties and Investments Ltd | Real estate | 2019 |
| Bazz Aerotech Limited | Manufacturing | 2014 |
| BB International Investments Ltd | Wholesale & retail | 2026 |
| BB IT Management Limited | Professional & scientific | 1999 |
| Bb&C Architects Limited | Professional & scientific | 2015 |
| BB7 Fusion Limited | Wholesale & retail | 2017 |
| BBI Cambridge Ltd | Education | 2020 |
| Bbrs Investments Ltd | Financial services | 2025 |
| BBS (Cambridge) Ltd | Construction | 2007 |
| BC Baby Care Company Limited | Extraterritorial | 2021 |
| BC Export Trading Co., Limited | Other services | 2021 |
| Bcc-T (Holdings) Limited | Other services | 2020 |
| BCK Investments Limited | Real estate | 2016 |
| BCR Infinity Architects Limited | Professional & scientific | 1989 |
| BCS Accounting Limited | Professional & scientific | 2007 |
| BCS Alternatives Limited | Professional & scientific | 2007 |
| BCS Cambs Ltd | Construction | 2017 |
| BCS Cosec Limited | Professional & scientific | 2000 |
| BCT Consultants Ltd. | Information & communication | 2023 |
| BDL Properties Ltd | Real estate | 2022 |
| BDS Architects Ltd | Professional & scientific | 1987 |
| BE Active Melbourn Limited | Arts & recreation | 2014 |
| BE Present Limited | Real estate | 2017 |
| BE Social Cambridge Ltd | Professional & scientific | 2020 |
| BEA Investment Properties Ltd | Real estate | 2024 |
| Bea's Beauty Retreat Ltd | Other services | 2023 |
| Beach Babies Limited | Education | 2002 |
| Beach Energy Limited | Professional & scientific | 2013 |
| Beach Physiotherapy Limited | Health & social care | 2016 |
| Beachstone Partners LLP | | 2023 |