| Colt Construction Ltd | Construction | 2003 |
| Colt Developments EOT Ltd | Administrative & support | 2025 |
| Colt Developments Limited | Professional & scientific | 2010 |
| Coltman Management Company Limited | Households | 1986 |
| Combined Engineering Services (Yorkshire) Ltd | Professional & scientific | 2022 |
| Combo Cars Ltd | Wholesale & retail | 2020 |
| Comedy Leisure Ltd | Hospitality | 2025 |
| Comeup Winch Ltd | Professional & scientific | 2024 |
| Comfort Nest Housing Ltd | Real estate | 2024 |
| Comfort Travel Services Ltd | Transport & logistics | 2026 |
| Comfystay Homes Ltd | Real estate | 2025 |
| Commerce Property Group Limited | Real estate | 2016 |
| Commercial Debt Recovery Services Limited | Professional & scientific | 1985 |
| Commercial Entrance Matting Limited | Construction | 2014 |
| Commercial Estimates Limited | Construction | 2007 |
| Commercial Facilities Management (CFM) Ltd | Professional & scientific | 2011 |
| Commercial Investments (Ferriby) Limited | Real estate | 2021 |
| Communique Education Recruitment Limited | Education | 2025 |
| Community Forward | Hospitality | 2012 |
| Community Triumph Limited | Administrative & support | 2009 |
| Community Ventures (Leeds) Limited | Construction | 2004 |
| Community Ventures (Management) Limited | Real estate | 2008 |
| Community Ventures Company (NO 1) Limited | Construction | 2004 |
| Community Ventures Investments Limited | Professional & scientific | 2010 |
| Community Ventures Midco (NO 1) Limited | Construction | 2004 |
| Community Ventures Partnerships Limited | Professional & scientific | 2011 |
| Community Ventures Primary Care Ltd | Real estate | 2019 |
| Compact Lifting Group Limited | Construction | 2022 |
| Company Assistant Ltd | Professional & scientific | 2025 |
| Compare Contact Limited | Information & communication | 2024 |
| Compass Training Ltd | Education | 2025 |
| Compassa Ltd. | Information & communication | 2017 |
| Compelo Limited | Extraterritorial | 2007 |
| Compelo Media Ltd | Extraterritorial | 2010 |
| Complete Access (Engineering & Services) Limited | Manufacturing | 2004 |
| Complete Building Services (UK) Ltd | Construction | 2006 |
| Complete Car Care Autocentre Ltd | Wholesale & retail | 2020 |
| Complete Cooling Ltd | Construction | 2024 |
| Complete Engineering Services (Hull) Limited | Professional & scientific | 2013 |
| Complete Event Management Company Limited | Arts & recreation | 2018 |
| Complete Facilities Management Limited | Administrative & support | 2011 |
| Complete Machining Services Limited | Manufacturing | 2001 |
| Complete Provisions Limited | Wholesale & retail | 2023 |
| Complete Refrigeration Services Ltd | Manufacturing | 2011 |
| Complete Tooling Services Limited | Manufacturing | 2015 |
| Composite Maintenance Systems Limited | Construction | 2010 |
| Composite Panel Services Ltd | Construction | 1997 |
| Comrad Motors Ltd | Wholesale & retail | 2026 |
| Comstar Property Limited | Real estate | 2015 |
| Comtec INT UK Limited | Wholesale & retail | 2016 |
| Concept Connections Ltd | Construction | 2023 |
| Concept Properties (Hull) Limited | Real estate | 2020 |
| Concept Sliding Solutions Limited | Manufacturing | 2016 |
| Concept Training and Recruitment Limited | Real estate | 1990 |
| Concepts for the Future Ltd | Administrative & support | 2017 |
| Conceptus UK Limited | Manufacturing | 2000 |
| Concy UK Ltd | Wholesale & retail | 2010 |
| Condor Pharma Ltd | Professional & scientific | 2010 |
| Conestock Limited | Real estate | 1985 |
| Confidential Recruitment Limited | Administrative & support | 2023 |
| Confined Spaces Training Services Limited | Education | 1988 |
| Confirm Bakery Ltd | Manufacturing | 2024 |
| Coniston Bills Garage Limited | Wholesale & retail | 2018 |
| Connect City Ltd | Transport & logistics | 2025 |
| Connect GAS & Plumbing Specialists Limited | Construction | 2003 |
| Connect Hosting Ltd | Information & communication | 2022 |
| Connoisseur Paving Limited | Administrative & support | 2024 |
| Connor Coffield Wind Ltd | Manufacturing | 2024 |
| Connor Coghill Ltd | Arts & recreation | 2019 |
| Connor CUP Master Limited | Wholesale & retail | 2026 |
| Connor Maher Consulting Ltd | Professional & scientific | 2026 |
| Connor Newman Limited | Professional & scientific | 2008 |
| Conroy Baker Ltd | Professional & scientific | 2021 |
| Conscious Real Estate Ltd | Real estate | 2025 |
| Conservative Home Limited | Information & communication | 2009 |
| Conservative Intelligence Limited | Information & communication | 2009 |
| Constant Construction Ltd | Construction | 2017 |
| Constantin Marin Ltd | Professional & scientific | 2025 |
| Construction Dust Association Ltd | Other services | 2023 |
| Construction Joinery Services (Yorkshire) Limited | Construction | 2017 |
| Construction Plant and Site Services Group Ltd | Construction | 2012 |
| Construction Safety Consultants CDM Limited | Construction | 2026 |
| Consult International (Holdings) Limited | Real estate | 2026 |
| Consult International Limited | Professional & scientific | 2000 |
| Consulting & Economics Ltd | Administrative & support | 2016 |
| Continental Electrical Components (U.K.) Limited | Manufacturing | 1976 |
| Continental Garden Cleaning Limited | Administrative & support | 2024 |
| Continental Holiday Homes Limited | Manufacturing | 2013 |
| Contract Services (Cleaning) Limited | Administrative & support | 2004 |
| Convaiance Limited | Professional & scientific | 2026 |
| Convenio Ltd | Professional & scientific | 2014 |
| Convert Case Ltd | Information & communication | 2018 |
| Cook (Damp & Decay) Limited | Extraterritorial | 2006 |
| Cook Group Limited | Other services | 1974 |
| Cook Homes Hull Limited | Households | 2023 |
| Cook Structural Repairs Limited | Extraterritorial | 2006 |
| Cook. Hair Studio Ltd | Other services | 2024 |
| Cool Consulting Limited | Professional & scientific | 2010 |
| Cool Holdings Limited | Professional & scientific | 2004 |
| Cool Mind Holdings Ltd | Financial services | 2020 |