| Bumperwest Limited | Real estate | 1986 |
| Bumperwest Management Ltd | Real estate | 2013 |
| Burrell, R & D Limited | Information & communication | 1994 |
| Business Brainwaves Ltd | Wholesale & retail | 2022 |
| Business Support Shop Ltd | Professional & scientific | 2010 |
| Butterwick Bakery Limited | Manufacturing | 2021 |
| Buyspace Ltd | Wholesale & retail | 2025 |
| BW Telecom Ltd | Construction | 2025 |
| Byword Limited | Professional & scientific | 2016 |
| C & M Boardman Ltd | Construction | 2018 |
| C a Thompson Limited | Transport & logistics | 2015 |
| C I Construction Wellingborough Limited | Administrative & support | 2025 |
| C P Tilbrook Ltd | Transport & logistics | 2023 |
| C&I Property Services Limited | Construction | 2026 |
| C.M.T.S. Limited | Professional & scientific | 1984 |
| C2E Energy Limited | Extraterritorial | 2025 |
| C2E Investment Group Ltd | Financial services | 2025 |
| C98 Ltd. | Information & communication | 2022 |
| Cabs-Xcel Ltd | Transport & logistics | 2024 |
| Cadismark Securities Limited | Financial services | 1991 |
| Calibre and Carats Ltd | Wholesale & retail | 2022 |
| Callon Group Limited | Professional & scientific | 2022 |
| Camera Box (Kettering) Limited | Other services | 2009 |
| Cando Care Co-Operative CIC | Health & social care | 2014 |
| Canmoly Healthcare Ltd | Health & social care | 2015 |
| CANOE2 Limited | Arts & recreation | 2009 |
| Capital Alliance Limited | Other services | 1999 |
| Carblife Limited | Wholesale & retail | 2012 |
| Carbon Bike Wheels Ltd | Wholesale & retail | 2019 |
| Carecues Ltd | Professional & scientific | 2025 |
| Caribbean Bay Limited | Real estate | 2018 |
| Carpe Ltd | Professional & scientific | 2021 |
| Carter & Cole Ltd | Information & communication | 2024 |
| Cartmel Distillers Limited | Manufacturing | 2005 |
| Castle RUM Company Ltd | Hospitality | 2018 |
| Caushaj Brothers Investment Ltd | Real estate | 2023 |
| Caushaj Brothers Property Ltd | Real estate | 2019 |
| Cavell Golf Ltd | Wholesale & retail | 2022 |
| CB Couriers Total Solutions Ltd | Construction | 2016 |
| CBS Tyres Ltd | Wholesale & retail | 2023 |
| CC Facades & Cladding Ltd | Construction | 2026 |
| CD Stores Limited | Wholesale & retail | 2026 |
| Ceen Global Ltd | Wholesale & retail | 2025 |
| Cento Technical Limited | Professional & scientific | 2014 |
| Central Consultancy and ADV Ltd | Professional & scientific | 2026 |
| Centurion Flyers Ltd | Other services | 2026 |
| CGS Recovery Ltd | Administrative & support | 2019 |
| Chadbon Brickwork Limited | Construction | 2005 |
| Chalie Richards & Company Limited | Wholesale & retail | 1991 |
| Chalie Richards Craft Wines and Spirits Limited | Wholesale & retail | 2016 |
| Chambers Paving Limited | Construction | 2022 |
| Chameleon Therapy Centre Ltd | Health & social care | 2021 |
| Chapelfield Construction Ltd | Construction | 2022 |
| Chargeheads Ltd | Wholesale & retail | 2021 |
| Charles Baker Engineering Ltd | Professional & scientific | 2024 |
| Charlie Store Ltd | Wholesale & retail | 2020 |
| Charlie's Construction Ltd | Construction | 2014 |
| Charmtailor Property Management Limited | Extraterritorial | 2001 |
| Charps Recruitment Ltd | Administrative & support | 2025 |
| Chase Enginering Ltd | Manufacturing | 2026 |
| Chax Works Limited | Professional & scientific | 2014 |
| Checkpoint Resilience Limited | Professional & scientific | 2025 |
| Cheeky Monkey Salon Group Ltd | Other services | 2018 |
| Cheers Leisure Limited | Hospitality | 2003 |
| Chelfarm LLP | | 2013 |
| Chelveston Estate Management Ltd | Real estate | 2018 |
| Chelveston Land Management Ltd | Real estate | 2018 |
| Chelveston Renewable Energy Limited | Energy | 2005 |
| Chenade Mitchell Holdings Limited | Administrative & support | 2017 |
| Chester Thomas Developments Limited | Construction | 2017 |
| Chhinas Transport Ltd | Transport & logistics | 2026 |
| Chiherachashe Ltd | Health & social care | 2021 |
| Chika Global Limited | Real estate | 2025 |
| Childs Homes Limited | Real estate | 2015 |
| Chilli Engineering Limited | Professional & scientific | 2014 |
| China Town Rushden Ltd | Hospitality | 2026 |
| Choice Furnishings Limited | Wholesale & retail | 2014 |
| Chris Building Services Bathroom Renovation Ltd | Construction | 2023 |
| Chris Building Services Home Renovation Ltd | Construction | 2020 |
| Chris Harley Properties Ltd | Real estate | 2020 |
| Chris P Tilbrook Limited | Transport & logistics | 2025 |
| Chrissy Grace Travel Ltd | Transport & logistics | 2023 |
| Church Oak Limited | Professional & scientific | 2015 |
| Churros Company Cromer Ltd | Hospitality | 2025 |
| Churros Time Ltd | Arts & recreation | 2023 |
| Cimplicity Fashions Limited | Wholesale & retail | 2024 |
| Circle Service JB Ltd | Hospitality | 2025 |
| Cirgraphics Limited | Manufacturing | 1982 |
| CJ Carpet & Windows Ltd | Construction | 2022 |
| CJ Wall Ltd | Professional & scientific | 2024 |
| CL Trucking Ltd | Transport & logistics | 2025 |
| CLA Automotive Ltd | Manufacturing | 2018 |
| Classic Conservatories (Earls Barton) Ltd | Construction | 2002 |
| Claygate Holdings Limited | Professional & scientific | 1990 |
| Clean Earth Waste Solutions Ltd | Water & waste | 2025 |
| Clean Smart Solutions Ltd | Administrative & support | 2017 |
| Clean Smart Stays Ltd | Real estate | 2023 |
| Cleanflexi Limited | Administrative & support | 2025 |
| Cleanwhiz Limited | Administrative & support | 2025 |
| Clear & Clean Window Cleaning Limited | Administrative & support | 2013 |