| Blue Light Support & Consultancy Ltd | Health & social care | 2022 |
| Blue Penny Developments Limited | Manufacturing | 2022 |
| Bluebell Abbey Limited | Wholesale & retail | 2016 |
| Bluebellcorby Ltd | Hospitality | 2026 |
| Bluefront Care Ltd | Health & social care | 2018 |
| Blues and Two's Catering Limited | Hospitality | 2017 |
| Bluesky Experiences at Deene Park Limited | Arts & recreation | 2023 |
| Blusheuk Limited | Other services | 2025 |
| BMC Conversions Limited | Wholesale & retail | 2018 |
| BMC Traders UK Ltd | Wholesale & retail | 2018 |
| BML Driver Ltd | Transport & logistics | 2026 |
| BMZ Consulting Limited | Professional & scientific | 2013 |
| BN Garage Limited | Wholesale & retail | 2023 |
| Bnmnfed Limited | Financial services | 2024 |
| BO Plumbing Ltd | Construction | 2022 |
| Bobasek Limited | Administrative & support | 2019 |
| Bobilnean Transport Ltd | Transport & logistics | 2019 |
| Boden Group Holdings Limited | Professional & scientific | 1997 |
| Boden Properties Limited | Real estate | 1994 |
| Bodoalex Ltd | Transport & logistics | 2019 |
| Bodybyhani Ltd | Wholesale & retail | 2025 |
| Bog&Dar Transport Ltd | Transport & logistics | 2025 |
| Bona Strategies Ltd | Professional & scientific | 2025 |
| Bondwell Support Ltd | Information & communication | 2026 |
| Book a Ride Ltd | Transport & logistics | 2025 |
| Booths Garden Offices Rental Limited | Administrative & support | 2018 |
| Booths Garden Studios Limited | Manufacturing | 2010 |
| Booths Wetherell Properties Limited | Real estate | 2020 |
| Bootprint Ltd | Information & communication | 2021 |
| Borders Ltd | Construction | 2021 |
| Bosjay Limited | Public administration | 2022 |
| Boss Academy Ltd | Other services | 2022 |
| Botolph Consultancy Limited | Professional & scientific | 2017 |
| Boundary ROW Opco Limited | Real estate | 2013 |
| Bowbridge (Abbots Langley) Limited | Construction | 2019 |
| Bowbridge (B&Mr) Limited | Construction | 2019 |
| Bowbridge (Fairham Pastures) Limited | Construction | 2024 |
| Bowbridge (Kier) Limited | Construction | 2019 |
| Bowbridge Cirencester Limited | Construction | 2012 |
| Bowbridge Estates Limited | Construction | 2018 |
| Bowbridge Homes (Bugbrooke) Limited | Construction | 2016 |
| Bowbridge Homes (Croxton Kerrial) Ltd | Construction | 2021 |
| Bowbridge Homes (Frisby) Limited | Construction | 2019 |
| Bowbridge Homes (Raunds) Limited | Construction | 2018 |
| Bowbridge Homes (Shipdham) Limited | Construction | 2019 |
| Bowbridge Homes Limited | Construction | 2013 |
| Bowbridge Homes Partnerships Limited | Construction | 2019 |
| Bowbridge Land Great Oakley Limited | Construction | 2024 |
| Bowbridge Land Limited | Real estate | 2013 |
| Bowbridge Shipdham Co OP Limited | Construction | 2019 |
| Bowbridge Strategic Land Limited | Professional & scientific | 2014 |
| Boygianny Limited | Transport & logistics | 2014 |
| BP Contracting (Corby) Ltd | Construction | 2018 |
| BPI 2010 Limited | Manufacturing | 1968 |
| BPI Limited | Real estate | 1983 |
| Bprex Plastic Packaging (India) Limited | Financial services | 1995 |
| Brats Day Nursery (Corby) Limited | Education | 1992 |
| Brattransport Ltd | Transport & logistics | 2021 |
| Brewfox Ltd | Construction | 2023 |
| Brian Watts Carpets (Wellingborough) Limited | Real estate | 1975 |
| Briana Trans Ltd | Other services | 2016 |
| Bricon Freight Services International U.K Ltd | Transport & logistics | 2025 |
| Bridge Motors Mobile Repairs Limited | Wholesale & retail | 2022 |
| Bright Quays Limited | Public administration | 2025 |
| Brigstock Sawmill Ltd | Wholesale & retail | 2025 |
| Brilliant Inspection Ltd | Wholesale & retail | 2025 |
| Briskly ISW Ltd | Health & social care | 2024 |
| Brit Talk Communications Ltd | Information & communication | 2020 |
| Brithene Films Limited | Extraterritorial | 1952 |
| British Geomembrane Association Limited | Other services | 2022 |
| British Polythene Industries Limited | Manufacturing | 1910 |
| British Polythene Limited | Manufacturing | 1939 |
| BRJ Hire Solutions Ltd | Manufacturing | 2015 |
| Brndx Limited | Professional & scientific | 2025 |
| Broad Green Compliance Limited | Professional & scientific | 2012 |
| Broadshadow Properties Limited | Construction | 2016 |
| Brook Development Management Company Limited | Real estate | 2006 |
| Brooke Construction Services Ltd | Construction | 2022 |
| Brookecare Limited | Health & social care | 2015 |
| Brookehub Limited | Real estate | 2025 |
| Brooklands Quality Cars Limited | Wholesale & retail | 2019 |
| Broshuis (UK) Limited | Wholesale & retail | 1978 |
| Brotherwood (Leicester) Limited | Construction | 2003 |
| Brunel Motors Limited | Wholesale & retail | 2017 |
| Brunel Signs Midlands Limited | Professional & scientific | 2019 |
| BSA Accounting Ltd | Professional & scientific | 2025 |
| BSE Health Limited | Health & social care | 2022 |
| BSF Transport Ltd | Transport & logistics | 2016 |
| BSG Transport Ltd | Transport & logistics | 2025 |
| BTC Citadel Engineering Limited | Professional & scientific | 2026 |
| BTC Citadel Limited | Manufacturing | 2022 |
| BTS Comms Ltd | Administrative & support | 2015 |
| Bubble Transport Ltd | Wholesale & retail | 2018 |
| Buchan DU Toit Precision Engineering Limited | Professional & scientific | 2017 |
| Bugieda Services Ltd | Wholesale & retail | 2011 |
| Build Strong Ltd | Construction | 2026 |
| Bulk Trade Solution Limited | Wholesale & retail | 2025 |
| Burgerlicious Corby Ltd | Hospitality | 2025 |
| Burgh Island Holdings Limited | Financial services | 2009 |
| Burgh Island Limited | Hospitality | 2001 |