| Contifibre Spa | | 2008 |
| Control Group International Limited | Information & communication | 2007 |
| Control INT Limited | Financial services | 2012 |
| Control Layer Ltd | Information & communication | 2016 |
| Convergent Systems Ltd. | Information & communication | 2016 |
| Cook & Baker Interiors Ltd | Professional & scientific | 2022 |
| Cook & Baker Kitchens Ltd | Professional & scientific | 2019 |
| Copeland's Transport Ltd. | Transport & logistics | 2020 |
| Copper Edge Ltd | Real estate | 2025 |
| Copperleaf Construction Limited | Extraterritorial | 2007 |
| Copperleaf Group Limited | Professional & scientific | 2007 |
| Copperleaf Homes Limited | Extraterritorial | 2007 |
| Copperleaf Limited | Construction | 2003 |
| Copperleaf Oxford Limited | Construction | 2012 |
| Copperleaf Plant Hire Limited | Extraterritorial | 2009 |
| Copperleaf Properties Limited | Real estate | 2008 |
| Coppice Building & Joinery Ltd | Construction | 2022 |
| Copyrite Hospitality Limited | Hospitality | 2020 |
| Corazon Solutions Ltd | Information & communication | 2023 |
| Corbettaz | Financial services | 2025 |
| Corbishley Construction Limited | Construction | 2002 |
| Core Construct Limited | Construction | 2014 |
| Core Construction (NW) Ltd | Construction | 2013 |
| Core of Care Limited | Health & social care | 2016 |
| Core Venture Ltd | Wholesale & retail | 2026 |
| Cori Projects Limited | Health & social care | 2025 |
| Cori Property Limited | Real estate | 2025 |
| Corlett Ltd | Other services | 2023 |
| Cornershop Coffee Ltd | Manufacturing | 2022 |
| Corporate Direct Fundraising Limited | Administrative & support | 1995 |
| Corporate EYE Web Services Limited | Professional & scientific | 2008 |
| Corporate Photos Ltd | Professional & scientific | 2026 |
| Corporate Venue Solutions Ltd | Administrative & support | 1996 |
| Cortadi Ltd | Hospitality | 2025 |
| Cosmetic Couture Training Newcastle Ltd | Education | 2026 |
| Cosmetics Factory Limited | Wholesale & retail | 2008 |
| Costa DEL Dean Limited | Real estate | 2021 |
| Costq Estimating Limited | Professional & scientific | 2024 |
| Cottage Street Ltd | Construction | 2016 |
| Cotton Tree Ltd | Hospitality | 2016 |
| Cottrills Limited | Manufacturing | 1999 |
| Coulton Holdings Limited | Financial services | 2023 |
| Countrywide Business Advisers Limited | Administrative & support | 2013 |
| Countrywide Office Management Limited | Real estate | 2017 |
| County Graphic Designs Limited | Administrative & support | 2002 |
| Coupers Care Fees Ltd | Administrative & support | 2013 |
| Courier Axis Limited | Transport & logistics | 2026 |
| Courtyard Kitchen Ltd | Wholesale & retail | 2020 |
| Covert Software Solutions Ltd | Information & communication | 2024 |
| COW Close Farm Limited | Manufacturing | 2013 |
| Cowpat Limited | Agriculture & fishing | 1998 |
| COX Electronic Security Limited | Administrative & support | 2025 |
| Cozchemix Limited | Information & communication | 2016 |
| CP Barnes Logistics Limited | Other services | 2024 |
| CP Logistics Ltd | Transport & logistics | 2025 |
| Cpgd Limited | Professional & scientific | 2024 |
| CPI Commercial Property Investments Ltd | Financial services | 2019 |
| CPR Consultants Ltd | Administrative & support | 2026 |
| Cqspv Ltd | Administrative & support | 2016 |
| CR Consulting Services Limited | Professional & scientific | 2017 |
| Craft Beer Fest Ltd | Arts & recreation | 2026 |
| Craft Studio Ltd | Information & communication | 2022 |
| Crag Inn Group Limited | Manufacturing | 2021 |
| Craig Addy Creative Limited | Professional & scientific | 2026 |
| Cranberry Documents Limited | Professional & scientific | 2016 |
| Cranford Property Management Limited | Households | 2023 |
| Cranford Sports Limited | Arts & recreation | 1964 |
| Cranmore Properties Limited | Administrative & support | 1981 |
| Crazy Legs Events Ltd | Arts & recreation | 2006 |
| CRE8 Facilities Limited | Administrative & support | 2014 |
| CRE8 Macclesfield Ltd | Education | 2011 |
| CRE8 Works Ltd | Administrative & support | 2011 |
| Creation Interiors Limited | Real estate | 2006 |
| Creative Impetus Associates Ltd | Professional & scientific | 2011 |
| Creative Kitchens, Bedrooms & Bathrooms Limited | Construction | 2003 |
| Creative Modern Digital Ltd | Information & communication | 2021 |
| Creative Modern Property Development Ltd | Construction | 2024 |
| Creative Sustainable Partnerships Ltd | Manufacturing | 2026 |
| Creditlogic Limited | Households | 1994 |
| Cremations Direct Dorset Ltd | Other services | 2019 |
| Crew Room Limited | Information & communication | 2011 |
| Cringlewood Court Management Limited | Extraterritorial | 1972 |
| Cristelo Graphics Ltd | Administrative & support | 2017 |
| Critical Path International Ltd | Professional & scientific | 2016 |
| Crnp Legal Limited | Administrative & support | 2019 |
| Crobio Ltd | Professional & scientific | 2019 |
| Croft Occupational Hygiene Limited | Professional & scientific | 2002 |
| Cromford Court Properties Limited | Real estate | 1935 |
| Cromley Limited | Extraterritorial | 2019 |
| Crompton Road Freehold Ltd | Households | 2018 |
| Crossfield Development Limited | Construction | 2018 |
| Crossfields Developments Limited | Construction | 2024 |
| Crossfire Media and Marketing Ltd | Professional & scientific | 2020 |
| Crossley Computing Solutions Ltd | Information & communication | 2016 |
| Crossride Limited | Financial services | 2015 |
| Crowholt Ltd | Hospitality | 2025 |
| Crown Building Solutions Limited | Construction | 2005 |
| Crown Festival Rights Limited | Arts & recreation | 2019 |
| Crown Festivals & Events Limited | Arts & recreation | 2019 |
| Crown Joinery Limited | Extraterritorial | 1999 |