| Co-Craft Ltd | Health & social care | 2012 |
| Coach House Automotive Consulting Ltd | Professional & scientific | 2019 |
| Coach Nick Paul Ltd | Wholesale & retail | 2023 |
| Coaches Properties Limited | Real estate | 2026 |
| Coachtravelhub Limited | Transport & logistics | 2026 |
| Coastal C&I Limited | Water & waste | 2025 |
| Cobalt Leasing Limited | Administrative & support | 2019 |
| Cobham Grange Limited | Real estate | 2009 |
| Cocktail Life Ltd | Wholesale & retail | 2021 |
| Cocoa Classic Truelovefilms Ltd | Information & communication | 2022 |
| Cocomasala Restaurant Limited | Hospitality | 2025 |
| Coconut Lagoon Limited | Hospitality | 2017 |
| Coconut Rice Srilankan Limited | Hospitality | 2025 |
| Cocuro Limited | Agriculture & fishing | 2021 |
| Codandchics Limited | Hospitality | 2025 |
| Coeliac UK | Health & social care | 1995 |
| Coffee Consultant Limited | Wholesale & retail | 2024 |
| Coffee Corporate Services Limited | Administrative & support | 2004 |
| Coffee on the Green Ltd | Hospitality | 2020 |
| Coffeeheaven Holdings Limited | Wholesale & retail | 2001 |
| Coffeeheaven International Limited | Manufacturing | 2001 |
| Coffeewerks Limited | Hospitality | 2021 |
| COG Film Limited | Information & communication | 2019 |
| Cogent Infotech Limited | Information & communication | 2017 |
| Cogent Realty Limited | Real estate | 2021 |
| Cognitera Ltd | Information & communication | 2004 |
| Cognitive Lantern Ltd | Information & communication | 2020 |
| Coin Developments Limited | Construction | 2019 |
| Coin Group Assets Ltd | Real estate | 2024 |
| Coinage Financials Ltd | Professional & scientific | 2018 |
| Coldfreight Limited | Transport & logistics | 2026 |
| Colds Europe Ltd | Education | 2024 |
| Colefree Ltd | Administrative & support | 2007 |
| Coleshill Capital Limited | Financial services | 2015 |
| Colin Clarke Construction Limited | Construction | 1997 |
| Colin Driving Ltd | Transport & logistics | 2024 |
| Collaborative Path Ltd | Professional & scientific | 2015 |
| Colliers Corner Developments Limited | Construction | 2011 |
| Colliers Farm Buildings Ltd | Real estate | 2020 |
| Colnside Executive Cars Ltd | Transport & logistics | 2005 |
| Colo Limited | Manufacturing | 2026 |
| Coltal Limited | Households | 1999 |
| Combe Consulting Ltd | Professional & scientific | 2025 |
| Comfort Mart Limited | Households | 2019 |
| Commercetest Limited | Information & communication | 1999 |
| Committed to Growth Limited | Professional & scientific | 2022 |
| Commodore Business Machines Ltd | Information & communication | 2025 |
| Community Action Training Limited | Education | 2013 |
| Community Collective CIC | Information & communication | 2017 |
| Community Flower Farm Ltd | Agriculture & fishing | 2021 |
| Community for Caring Limited | Education | 2022 |
| Community Matters Penn Limited | Real estate | 2023 |
| Community Matters Solutions Ltd | Information & communication | 2026 |
| Compare Travel Services Limited | Other services | 2020 |
| Compine Developments (Wootton) Limited | Extraterritorial | 1990 |
| Complete Film Servicing Limited | Administrative & support | 2017 |
| Complete Freight Services Ltd | Transport & logistics | 2022 |
| Complete I.T. Limited | Extraterritorial | 2022 |
| Complete Landscapes Ltd | Administrative & support | 2019 |
| Complete Office Limited | Wholesale & retail | 2025 |
| Complete Vehicle Solutions Berkshire Ltd | Professional & scientific | 2026 |
| COMPLIANCE2425 Ltd | Professional & scientific | 2024 |
| COMPLY2GO Ltd | Information & communication | 2023 |
| Composites and Bifolds Ltd | Manufacturing | 2012 |
| Computer Education Management Association Europe Limited | Other services | 1994 |
| Computer Friends I.T Services Ltd | Information & communication | 2014 |
| Computer Gallery Ltd | Wholesale & retail | 2023 |
| Comunidade Evangelica Projeto Vida High Wycombe Ltd | Other services | 2022 |
| Comwood Croydon Limited | Hospitality | 2005 |
| Comwood Holdings Ltd. | Real estate | 2016 |
| Comwood London Limited | Real estate | 2004 |
| Comwood Properties Ltd. | Other services | 2016 |
| CON to Empanadas Ltd | Hospitality | 2026 |
| Con-Serv Limited | Professional & scientific | 2000 |
| Concentric Capital Group Ltd | Financial services | 2026 |
| Concept Building & Maintenance Ltd | Construction | 2025 |
| Concept Group Interiors Limited | Professional & scientific | 2019 |
| Concept Properties Loudwater Ltd | Arts & recreation | 2016 |
| Concepts and Creations Limited | Construction | 2022 |
| Concepts Traders Limited | Wholesale & retail | 2025 |
| Concierge VET Ltd | Professional & scientific | 2022 |
| Concordia Heritage Limited | Wholesale & retail | 2026 |
| Confirm Comply Ltd | Information & communication | 2025 |
| Congruent Ltd | Information & communication | 2014 |
| Connect Cart Ltd | Wholesale & retail | 2024 |
| Connect Optics Limited | Administrative & support | 2007 |
| Connected UK Solutions Limited | Information & communication | 2024 |
| Connecting Dots Ltd | Information & communication | 2012 |
| Connecting Research Ltd | Professional & scientific | 2026 |
| Connector Solutions Limited | Manufacturing | 2006 |
| Conquest Supplies Ltd | Construction | 2020 |
| Conscious Canine Coach Ltd | Agriculture & fishing | 2025 |
| Consilio Property Limited | Construction | 2017 |
| Constable Credit Limited | Financial services | 1990 |
| Constant Air Systems Limited | Construction | 1965 |
| Consult Right Ltd | Professional & scientific | 2019 |
| Consultant Cardiologist Ltd | Health & social care | 2024 |
| Consulting Alternatives Limited | Professional & scientific | 2005 |
| Consulting for Real People Ltd | Professional & scientific | 2023 |
| Consulting Innovations Limited | Administrative & support | 2004 |