| CFR Events Ltd | Hospitality | 2024 |
| Chadwells Estate Agents Limited | Real estate | 2021 |
| Chageol Properties Limited | Real estate | 2017 |
| Chain Free Property Buyers Ltd | Real estate | 2026 |
| Chain Free Property Sourcers Ltd | Real estate | 2026 |
| Champion Marquee Structures and Events Ltd | Manufacturing | 2025 |
| Chancellor Developments Limited | Construction | 2022 |
| Charley Louise Limited | Arts & recreation | 2024 |
| Cheswold Merchants Limited | Extraterritorial | 2012 |
| Chex Limited | Professional & scientific | 1993 |
| Chris Chambers Consulting Ltd | Health & social care | 2011 |
| Chrysos H.R. Solutions Limited | Education | 2005 |
| Churchgate Grill Ltd | Hospitality | 2025 |
| Churchill Developments Limited | Construction | 1999 |
| Citynet Insurance Brokers Limited | Financial services | 2000 |
| Citynet London Holdings Ltd | Financial services | 2012 |
| CJ Milligan Smith Limited | Health & social care | 2016 |
| CJ Surfaces Ltd | Construction | 2015 |
| CJF Commercials Limited | Wholesale & retail | 2017 |
| CJJ Design and Development Limited | Construction | 2001 |
| CJM Railway Limited | Manufacturing | 2016 |
| CL Fitness and Health Limited | Other services | 2019 |
| Clancy Briggs Cycling Academy CIC | Education | 2019 |
| Claremont Early Years Limited | Education | 2002 |
| Clarke Chapman Aftermarket Limited | Professional & scientific | 2000 |
| Clarke Chapman Facilities Management Limited | Administrative & support | 2000 |
| Clarke Chapman Limited | Manufacturing | 2000 |
| Clarke Chapman Machining Limited | Professional & scientific | 2006 |
| Clarke Chapman Manufacturing Limited | Professional & scientific | 2000 |
| Claudius Peters (UK) Limited | Professional & scientific | 1973 |
| Claydon Legal Services Limited | Professional & scientific | 2022 |
| Clayton Locomotives Limited | Manufacturing | 2025 |
| Clear Site Services Ltd | Construction | 2021 |
| Clearwater Lakes Fishery Limited | Agriculture & fishing | 2004 |
| CLICK4HEAT Limited | Wholesale & retail | 2021 |
| Clockpress Holdings Limited | Financial services | 2022 |
| Clockpress Limited | Manufacturing | 1989 |
| Cloud Accountancy Limited | Professional & scientific | 2010 |
| Clumber Blinds Ltd | Wholesale & retail | 2021 |
| Clumber Construction Limited | Construction | 2008 |
| CM Snowden Building and Roofing Limited | Construction | 2025 |
| Cmairsoft Ltd | Arts & recreation | 2023 |
| CME Contracts Ltd | Construction | 2018 |
| CMK Construction & Plant Hire Ltd | Construction | 2025 |
| CMK Home Improvements Ltd | Construction | 2023 |
| CMS Foods Ltd | Hospitality | 2020 |
| Coachcei Limited | Other services | 2017 |
| Coaching Inns (North) Limited | Hospitality | 2007 |
| Cobra Holdings Limited | Professional & scientific | 2005 |
| Cobra Network Limited | Other services | 2003 |
| Cobra of the North Ltd | Information & communication | 2017 |
| Coe-Mix RMC Limited | Extraterritorial | 2010 |
| Colby Cameron Estates Ltd | Real estate | 2026 |
| Commercial Finance Ltd. | Financial services | 2007 |
| Compassionate Care Team Ltd | Health & social care | 2012 |
| Compliant Solutions Group Ltd | Professional & scientific | 2020 |
| Comuspace CIC | Information & communication | 2023 |
| Conduit Tea Gardens Limited | Hospitality | 2001 |
| Conference Technologies UK Limited | Administrative & support | 2006 |
| Construction Training Accreditations Limited | Construction | 2020 |
| Consulting for Business Limited | Professional & scientific | 2002 |
| Continental Gold Retford Limited | Construction | 2022 |
| Continuity Promotions Limited | Real estate | 1988 |
| Contour Archaeology Ltd | Construction | 2023 |
| Convicteduk Ltd | Wholesale & retail | 2021 |
| Conway Security Services Limited | Administrative & support | 1996 |
| Cook & Phillips Construction Ltd | Construction | 2023 |
| Coolsilk Limited | Professional & scientific | 2013 |
| Coolsilk Property & Investment Limited | Professional & scientific | 2013 |
| Cooper Mills Building Contractors Limited | Construction | 2021 |
| Cooper Solutions Limited | Information & communication | 2004 |
| Coopers (Dunham) Limited | Administrative & support | 1958 |
| Coopers Cabin Craft Limited | Manufacturing | 2019 |
| Corax Concepts Limited | Construction | 2016 |
| Core Alignment Communications Ltd | Information & communication | 2018 |
| Core Consult Services Limited | Professional & scientific | 2014 |
| Core Homes Limited | Real estate | 2016 |
| Core Property Group Limited | Households | 2015 |
| Coremedica Wellness Group Ltd | Health & social care | 2025 |
| Countywear Limited | Wholesale & retail | 2011 |
| Cowans Sheldon Limited | Professional & scientific | 2000 |
| CPE Travel Ltd | Administrative & support | 2018 |
| Craft Source Limited | Wholesale & retail | 2013 |
| Crate Property Investments Limited | Real estate | 2020 |
| Crazy 88 Collective Ltd | Other services | 2025 |
| Createinn Limited | Manufacturing | 2004 |
| Creo Creative Studio Ltd | Professional & scientific | 2025 |
| Crossfit Retford Ltd | Arts & recreation | 2022 |
| Crossing the Borders Ltd | Information & communication | 2017 |
| Crosslink Technology Holdings Limited | Financial services | 2018 |
| Crown Informatics Limited | Information & communication | 2013 |
| Crown Inn PUB Limited | Hospitality | 2025 |
| Crowntop Roofing Ltd | Construction | 2025 |
| Cryo Retford Ltd | Health & social care | 2022 |
| CSG Consultants Ltd | Professional & scientific | 2025 |
| CSL Commercial Properties Limited | Real estate | 2019 |
| CSL Comprop Limited | Financial services | 2025 |
| CSL Group Holdings Limited | Financial services | 2025 |
| CSL Group Investments Limited | Financial services | 2019 |
| CSL Group Services Limited | Information & communication | 2006 |