| Bourne END Auction Rooms Limited | Professional & scientific | 1992 |
| Bourton Liquid Waste Disposal Ltd | Water & waste | 2022 |
| Bourton Liquid Waste Limited | Water & waste | 2021 |
| Boxspark Ltd | Information & communication | 2016 |
| BP Electronics Limited | Professional & scientific | 2007 |
| Bradbury Yates Limited | Wholesale & retail | 2020 |
| Braley Limited | Arts & recreation | 2019 |
| Brand Workshop Ltd | Administrative & support | 2024 |
| Brander-Gleghorn Holdings Limited | Financial services | 2017 |
| Brandline Products Alfresco Limited | Manufacturing | 2023 |
| Braunston Fryer Limited | Hospitality | 2018 |
| Braunston Garage Limited | Wholesale & retail | 2006 |
| Braunston Marina Limited | Arts & recreation | 1988 |
| Brian Marketing Ltd | Professional & scientific | 2022 |
| Brian Porter Ltd | Information & communication | 2013 |
| Brieflow Ltd | Information & communication | 2026 |
| Bright EYE Business Consulting Services Limited | Professional & scientific | 2022 |
| Bright Legal Services Limited | Professional & scientific | 2024 |
| Brighten My Garden Ltd | Administrative & support | 2023 |
| BRIGHTFUTURE88 Limited | Hospitality | 2025 |
| Brigid Turner & Co Limited | Real estate | 2009 |
| Brik Construction Ltd | Construction | 2024 |
| Brik Renewables Ltd | Construction | 2025 |
| Britannia Pizza House Limited | Hospitality | 2025 |
| Broadstones Group Ltd | Financial services | 2021 |
| Broadstones Solutions Ltd | Information & communication | 2018 |
| Brockhall Fabrics Limited | Wholesale & retail | 2010 |
| Brodie Property Management Limited | Households | 2014 |
| Brownlands Holdings Limited | Financial services | 2024 |
| Bryco Group Limited | Wholesale & retail | 1973 |
| Bryco Holdings Limited | Financial services | 2022 |
| BS Mold Construction Ltd | Construction | 2020 |
| BTB Exhausts Limited | Manufacturing | 1983 |
| BTW Services Limited | Real estate | 2018 |
| Buda Base Limited | Wholesale & retail | 2014 |
| BUG Music Limited | Information & communication | 2024 |
| Build Skills Northants Ltd | Construction | 2024 |
| Building APM Ltd | Construction | 2020 |
| Bullworthy (Holdings) Limited | Other services | 2010 |
| Bunkie and Muggets Property Development Limited | Real estate | 2025 |
| Burterry Services Ltd | Construction | 2018 |
| Burton Brothers Ltd | Construction | 2020 |
| Burton Cater Solutions Ltd | Hospitality | 2025 |
| Business Finance Services Limited | Financial services | 2002 |
| Business Growth Formula Ltd | Administrative & support | 2024 |
| Butnaru.Ionut.Ltd Limited | Transport & logistics | 2015 |
| BWJ Auto Tech Ltd | Wholesale & retail | 2025 |
| Byfield Residents Management Company Limited | Households | 2022 |
| Byfield Self Store Limited | Administrative & support | 2011 |
| Byzantine Capital Limited | Financial services | 2018 |
| Byzantine Investment Properties Ltd | Real estate | 2024 |
| BZ123 Ltd | Wholesale & retail | 2024 |
| C & G Events Limited | Professional & scientific | 2018 |
| C Caygill Building Services Limited | Construction | 2015 |
| C Home Inovision Ltd | Construction | 2016 |
| C J Y Carpentry Limited | Manufacturing | 2019 |
| C&C Eyles Properties Limited | Real estate | 2026 |
| C&C Fitness Ltd | Arts & recreation | 2022 |
| C&R Pro Limited | Transport & logistics | 2023 |
| C&S Carpentry & Construction Ltd | Construction | 2025 |
| C.G.S. Machine Care Ltd | Manufacturing | 2003 |
| C.M.J Paving Ltd | Construction | 2023 |
| C.M.N.A. Transport Logistic Ltd | Administrative & support | 2018 |
| C4 Secure Limited | Information & communication | 2019 |
| C5 Solutions Limited | Transport & logistics | 2020 |
| Cablectrix Limited | Administrative & support | 1981 |
| Cad-It UK Ltd | Professional & scientific | 2002 |
| Cagecraft Ltd | Wholesale & retail | 2013 |
| Cameron & Cameron Holdings Limited | Financial services | 2026 |
| Campbell Digital Enterprises Ltd | Professional & scientific | 2020 |
| Camper Vinn Accessories Ltd | Wholesale & retail | 2024 |
| Camper Vinn Ltd | Wholesale & retail | 2024 |
| Canine Guard Ltd | Administrative & support | 2025 |
| Cannon Communications Ltd | Information & communication | 2010 |
| Capac Industrial Limited | Professional & scientific | 2013 |
| Capes Consulting Limited | Professional & scientific | 2014 |
| Caplen Family Investments Limited | Financial services | 2026 |
| Capstone Software Ltd | Information & communication | 2026 |
| Caradok Limited | Wholesale & retail | 2021 |
| Carbon Claw Sports Ltd | Wholesale & retail | 2014 |
| Carbon Free Homes Limited | Construction | 2007 |
| Carbone Scientific Co., Ltd | Professional & scientific | 2008 |
| Care & Shine Services Ltd | Administrative & support | 2025 |
| Careson Natural Health Products (UK) Co., Ltd | Professional & scientific | 2013 |
| Carhoots Limited | Wholesale & retail | 2001 |
| Carm Investments Ltd. | Professional & scientific | 2018 |
| Carter Shield Consultancy Limited | Information & communication | 2021 |
| Carthovel Limited | Financial services | 2024 |
| Cartwright Woodwork Limited | Construction | 2019 |
| Casa Development Holdings Limited | Professional & scientific | 2020 |
| Casa Maison Ltd | Real estate | 2024 |
| Cash & Carry Carpets (Banbury) Limited | Other services | 2012 |
| CASHFLOW1 Ltd | Professional & scientific | 2020 |
| Catalin&Madalina Ltd | Transport & logistics | 2019 |
| Catesby Holdings Limited | Financial services | 2024 |
| Cathay Industrial Biotech (UK) Limited | Professional & scientific | 2011 |
| Cathy Finance Holding Co., Ltd | Professional & scientific | 2016 |
| Caty Ltd | Transport & logistics | 2013 |
| Cavello Group Limited | Construction | 2019 |
| Cavello Investments Limited | Financial services | 2023 |