| Click Swift Limited | Health & social care | 2017 |
| Climax Global Ltd | Information & communication | 2023 |
| Clinical Services Ltd | Professional & scientific | 2012 |
| Cliniweave Limited | Health & social care | 2001 |
| Clinton Property Management Limited | Households | 2003 |
| Cloud Oriental Limited | Wholesale & retail | 2024 |
| Cloudaavintage Ltd | Wholesale & retail | 2026 |
| Cloudful Limited | Information & communication | 2022 |
| Cluckroo Limited | Hospitality | 2026 |
| CM Group Essex Ltd | Hospitality | 2018 |
| CMD Construction & Build Ltd | Construction | 2019 |
| Cmmm Ltd | Extraterritorial | 2013 |
| CMP Steel Services Ltd | Construction | 2019 |
| CN UK Consultants Limited | Professional & scientific | 2016 |
| Cncqrwrld Ltd | Wholesale & retail | 2025 |
| Co.Ba.Co Construction Limited | Construction | 2017 |
| COA Immensity Limited | Information & communication | 2022 |
| Cobin Property Management Limited | Households | 2004 |
| Coco IVY Cockfosters Ltd | Extraterritorial | 1993 |
| Coco IVY Fashion Ltd | Wholesale & retail | 2020 |
| Code for Life Ltd | Education | 2026 |
| Codensmile Ltd | Information & communication | 2024 |
| Coding Blocks Ltd | Information & communication | 2023 |
| Coffee and Crayons Limited | Professional & scientific | 2017 |
| Cogswell & Harrison (Gunmakers) Limited | Manufacturing | 1982 |
| Cogswell & Harrison Limited | Professional & scientific | 1993 |
| Coinshop Ltd | Wholesale & retail | 2024 |
| Colbern Limited | Administrative & support | 2004 |
| Cold Tea Ltd | Hospitality | 2020 |
| Cole Climate Solutions Limited | Energy | 2024 |
| Cole Green Properties Fareham Ltd | Professional & scientific | 2016 |
| Cole Green Properties Limited | Real estate | 2015 |
| Colleyflowers Ltd | Arts & recreation | 2024 |
| Colour Image (ST Albans) Limited | Administrative & support | 2004 |
| Comfort Air Ltd | Construction | 2014 |
| Comfy Soles Chiropody Ltd | Health & social care | 2014 |
| Compass 365 Ltd | Education | 2025 |
| Compassion Caregivers Ltd | Health & social care | 2026 |
| Complete Camera Platforms Ltd | Administrative & support | 2011 |
| Compufix Limited | Extraterritorial | 1990 |
| Computacenter (FMS) Limited | Extraterritorial | 1999 |
| Computacenter (Management Services) Limited | Extraterritorial | 1999 |
| Computacenter (Mid-Market) Limited | Extraterritorial | 1997 |
| Computacenter (UK) Limited | Information & communication | 1981 |
| Computacenter Distribution Limited | Extraterritorial | 1986 |
| Computacenter Germany Holdings Limited | Financial services | 2025 |
| Computacenter Group Holdings Limited | Financial services | 2025 |
| Computacenter Leasing Limited | Extraterritorial | 1989 |
| Computacenter Maintenance Limited | Extraterritorial | 1988 |
| Computacenter Overseas Holdings Limited | Extraterritorial | 1997 |
| Computacenter Quest Trustees Limited | Extraterritorial | 1999 |
| Computacenter Services Limited | Extraterritorial | 1988 |
| Computacenter Software Limited | Extraterritorial | 1989 |
| Computacenter Solutions Limited | Extraterritorial | 1998 |
| Computacenter Training Limited | Extraterritorial | 1989 |
| Computacenter Trustees Limited | Extraterritorial | 1998 |
| Computadata Limited | Extraterritorial | 1983 |
| Computer Aided Portfolio Design Limited | Information & communication | 2007 |
| Computer Services Group Limited | Extraterritorial | 1981 |
| Computer Technology Services Ltd | Wholesale & retail | 2018 |
| Connect and Build Ltd | Administrative & support | 2016 |
| Connect Direct Shipping Ltd | Transport & logistics | 2016 |
| Connectbingo Ltd | Information & communication | 2026 |
| Connected Utilities Limited | Construction | 2025 |
| Conquer Capital Ltd | Real estate | 2024 |
| Conscious Curtains Ltd | Manufacturing | 2023 |
| Constantin Purcea Ltd | Transport & logistics | 2019 |
| Construction Workforce Limited | Construction | 2022 |
| Continuum Technologies Ltd | Information & communication | 2026 |
| Contract Abseiling Limited | Construction | 2011 |
| Conxor Global Ltd | Wholesale & retail | 2026 |
| Coodens Property Ltd | Real estate | 2019 |
| Coombes & Wright Mortgage Solutions Limited | Financial services | 2014 |
| Cooney's Investments Limited | Real estate | 2024 |
| Coopie Services Ltd | Transport & logistics | 2024 |
| Copperance Ltd | Construction | 2026 |
| Copperlane Solutions Limited | Professional & scientific | 2026 |
| Corals Cuisine Ltd | Hospitality | 2021 |
| Core Exercise Clinics Limited | Professional & scientific | 2006 |
| Corhriggers Ltd | Construction | 2025 |
| Cormar Holdings Limited | Professional & scientific | 1993 |
| Cornel Cosmin Limited | Transport & logistics | 2018 |
| Cortlands Management Company Limited | Households | 2021 |
| Cosmic Universe Enterprises Ltd | Administrative & support | 2013 |
| COSTI76 Ltd | Transport & logistics | 2025 |
| Coulson Construction Consultancy Limited | Professional & scientific | 2026 |
| Countess Anne Church of England School | Education | 2013 |
| Country Club and Leisure Limited | Arts & recreation | 2009 |
| Country Clubs (UK) Limited | Professional & scientific | 2009 |
| County Hall (Westminster) Limited | Real estate | 2021 |
| Couture Avenue Limited | Wholesale & retail | 2023 |
| Couturecargo Limited | Wholesale & retail | 2023 |
| Cozynest Rentals Limited | Real estate | 2024 |
| CPI - Ashford Limited | Real estate | 2024 |
| CPI - Barnet Limited | Real estate | 2024 |
| CPI - Bolton Farnworth Limited | Real estate | 2026 |
| CPI - Bolton Manchester Road Limited | Real estate | 2024 |
| CPI - Brentwood Gateway Park Limited | Real estate | 2024 |
| CPI - Bury Limited | Real estate | 2024 |
| CPI - Canterbury Sturry Road Limited | Real estate | 2024 |