| Corbridge Consultants Ltd | Professional & scientific | 2022 |
| Cordia Business Services Limited | Extraterritorial | 2002 |
| Corevex Ltd | Information & communication | 2025 |
| Corinium Innovation Limited | Professional & scientific | 2009 |
| Corinthian International Limited | Professional & scientific | 2024 |
| Cornflower Limited | Manufacturing | 1996 |
| Cornflower Travel Retail Limited | Wholesale & retail | 2025 |
| Cornwall News Media Limited | Information & communication | 1961 |
| Corporate Amusement Holdings Limited | Financial services | 2025 |
| Corporate Amusement Services Limited | Other services | 2001 |
| Corporate Executive Search Limited | Wholesale & retail | 2016 |
| Corr Bristol Limited | Administrative & support | 2019 |
| Corrus Limited | Manufacturing | 2000 |
| Cortexagency Ltd | Information & communication | 2026 |
| Corvid Metalworks Ltd | Manufacturing | 2024 |
| Cosmetic Bases Limited | Manufacturing | 2017 |
| Cosmos Energy Ltd. | Manufacturing | 2012 |
| Costclever Limited | Professional & scientific | 2015 |
| Cotswold Meat Company Limited | Hospitality | 1991 |
| Cottage Stoves Limited | Wholesale & retail | 2010 |
| Cotton Barons Limited | Extraterritorial | 2020 |
| Country Construction & Landscapes Ltd | Construction | 2021 |
| Countryside Books Limited | Professional & scientific | 1989 |
| Countryways Heating and Property Services Limited | Construction | 2022 |
| Countrywide Environmental Ltd | Administrative & support | 2017 |
| County Electrical Services + C.E.S. Security Alarms Limited | Construction | 1983 |
| Courtwood Enterprises Limited | Arts & recreation | 2009 |
| Covenant for Childhood Ltd | Other services | 2024 |
| Cowleaze Services Limited | Professional & scientific | 2004 |
| Coys Polymers Limited | Other services | 2015 |
| CP Endurance Training Ltd | Arts & recreation | 2022 |
| CR Landscapes Limited | Administrative & support | 2014 |
| Craft Leadwork and Roofing Ltd | Construction | 2019 |
| Craftsman Newbury Limited | Wholesale & retail | 2000 |
| Craig Borlase Limited | Information & communication | 2005 |
| Craven Corporation Limited | Professional & scientific | 2003 |
| Craven Court (Residents) Limited | Real estate | 1984 |
| Craven House (Newbury) Management Company Limited | Households | 2005 |
| Crawford Dougall International Limited | Administrative & support | 2010 |
| Crayon Films Ltd | Information & communication | 2019 |
| Cream Electrical Services Ltd | Construction | 2020 |
| CREAT3D Ltd | Manufacturing | 2013 |
| Createsome Limited | Professional & scientific | 2003 |
| Creatify Group Ltd | Administrative & support | 2020 |
| Creative Dental Laboratory Limited | Health & social care | 2002 |
| Creative IT Solutions Limited | Information & communication | 2011 |
| Creche OUT Limited | Health & social care | 2007 |
| Cresco Cyber Consulting Limited | Information & communication | 2024 |
| Crest Contractors Limited | Professional & scientific | 2024 |
| CRG Property Solutions Ltd | Construction | 2025 |
| Cricketts of Berkshire Limited | Real estate | 2003 |
| Crooklets Management Limited | Households | 2023 |
| Cross Lanes Developments Ltd | Construction | 2026 |
| Crosscoat Ltd | Wholesale & retail | 2002 |
| Crosswell Orthopaedic Care Ltd | Health & social care | 2024 |
| Crown Coffee Limited | Administrative & support | 1984 |
| Crown House Newbury Limited | Real estate | 2019 |
| Crrj Limited | Real estate | 2019 |
| Cruidin Training & Consultancy Limited | Administrative & support | 2014 |
| Crystal Baths Ltd | Professional & scientific | 2018 |
| Csbw Ltd | Wholesale & retail | 2021 |
| CSG Contracts Ltd | Construction | 2015 |
| CSG Global Limited | Financial services | 2022 |
| CSG Roofing Supplies Ltd | Wholesale & retail | 2022 |
| CSS (2024) Ltd | Financial services | 2025 |
| CSS Recycling Ltd | Water & waste | 2013 |
| Cube-It Solutions & Consulting Services Ltd | Information & communication | 2018 |
| Cucumber Operating Systems Ltd. | Information & communication | 2019 |
| CUE Sports Management Services Ltd | Professional & scientific | 2022 |
| CUE the BBQ Limited | Wholesale & retail | 2020 |
| Cultivate Comms Limited | Professional & scientific | 2025 |
| Culturapeak Ltd | Administrative & support | 2024 |
| Cumulus Coaching Ltd | Professional & scientific | 2022 |
| Cuoca Ltd | Professional & scientific | 2025 |
| CUP & Sourcer Limited | Administrative & support | 2012 |
| Curio by Connie Ltd | Manufacturing | 2025 |
| Curioso Studio Limited | Professional & scientific | 2024 |
| Curling 1961 Limited | Extraterritorial | 2016 |
| Cutting Bar Limited | Other services | 2003 |
| Cutting Lines Limited | Construction | 2015 |
| CVP Capital Limited | Professional & scientific | 2019 |
| CWD Ltd | Real estate | 2019 |
| CWM Transport Ltd | Transport & logistics | 2013 |
| Cwpd Ltd | Real estate | 2016 |
| Cybercrowd Limited | Information & communication | 2016 |
| Cyberdomains Ltd | Information & communication | 2023 |
| Cyberhive Ltd | Information & communication | 2000 |
| Cybersift Limited | Manufacturing | 2010 |
| Cygnity Medical Writing Ltd | Professional & scientific | 2026 |
| Cykay Limited | Administrative & support | 2019 |
| Czajkowski Trader Limited | Construction | 2012 |
| D & a Consulting Limited | Professional & scientific | 2026 |
| D & S Roofing Single PLY Contractors Ltd | Construction | 2009 |
| D & T Bell Limited | Professional & scientific | 2013 |
| D a Collins Scaffolding Limited | Construction | 2011 |
| D a Groundworks Ltd | Professional & scientific | 2017 |
| D a Woods Orthopaedics Ltd. | Health & social care | 2013 |
| D R Communications Limited | Information & communication | 2004 |
| D Rail Ltd | Construction | 2015 |
| D&C Group UK Ltd | Transport & logistics | 2022 |