| Complete Injury Claims Ltd | Other services | 2016 |
| Complete Metal Finishing Ltd | Professional & scientific | 2013 |
| Complete Neuro Physio Limited | Extraterritorial | 2020 |
| Complete PA Ltd | Administrative & support | 2019 |
| Complete Refurbishment Midlands Ltd | Construction | 2025 |
| Complete Regalia Ltd | Wholesale & retail | 2025 |
| Complete Review Ltd. | Administrative & support | 2019 |
| Complete Surfacing Limited | Construction | 2025 |
| Complex Care Ltd | Extraterritorial | 2023 |
| Complexions Gym Limited | Administrative & support | 2010 |
| COMPROMISE2015 Ltd | Manufacturing | 2015 |
| Compton Care Group Limited | Wholesale & retail | 1982 |
| Compton Care Lottery Limited | Arts & recreation | 1996 |
| Compton Garden Restaurant Ltd | Hospitality | 2024 |
| Compton Removals Ltd | Transport & logistics | 2024 |
| Compton Retail Limited | Wholesale & retail | 2019 |
| Compton Takeaway Ltd | Hospitality | 2024 |
| Compucraft Limited | Information & communication | 1987 |
| Compupay Services Limited | Administrative & support | 2020 |
| Computer Administration Services Limited | Information & communication | 1984 |
| Conavalla Consulting Ltd | Administrative & support | 2009 |
| Concept Accountancy & Taxation Services Ltd | Professional & scientific | 2024 |
| Concept Cuisine Ltd | Hospitality | 2026 |
| Concept Cupboards Ltd | Wholesale & retail | 2018 |
| Concept Education Services Ltd | Administrative & support | 2012 |
| Concept Formulas LLP | | 2015 |
| Concept RE Limited | Real estate | 2025 |
| Concept Technical Services Ltd | Administrative & support | 1983 |
| Concept XR Ltd. | Information & communication | 2022 |
| Conception Avenue Limited | Information & communication | 2018 |
| Concero Education Technology Limited | Information & communication | 2023 |
| Concero Technology Services Limited | Information & communication | 2016 |
| Concero UK Limited | Information & communication | 2008 |
| Concrete Patterning Supplies Limited | Construction | 1992 |
| CONCRETE4U1 Limited | Manufacturing | 2023 |
| Conduct Education Behaviour Change Services Ltd | Education | 2026 |
| Conform UK Concrete Flooring Ltd | Construction | 2022 |
| Conform UK Plant Limited | Construction | 2022 |
| Conicdrop Limited | Construction | 1977 |
| Coniston 108 Limited | Real estate | 2026 |
| Coniston Facilities Limited | Construction | 2026 |
| Connaught House Trust Limited | Professional & scientific | 2025 |
| Connaught House Veterinary Group Limited | Professional & scientific | 2024 |
| Connect With David Limited | Other services | 2025 |
| Connect X Solutions Ltd | Wholesale & retail | 2026 |
| Connected Countrywide Ltd | Transport & logistics | 2020 |
| Connected Partnership Limited | Education | 2012 |
| Connection Care Ltd | Administrative & support | 2023 |
| Connections UK Head Office Limited | Other services | 2021 |
| Connections UK Network Ltd | Other services | 2021 |
| Connectsport CIC | Information & communication | 2024 |
| Connexa Legal Limited | Information & communication | 2022 |
| Conniemash Limited | Health & social care | 2015 |
| Connolley Metals Limited | Wholesale & retail | 2015 |
| Connor Parker Ltd | Administrative & support | 2026 |
| Connor's Construction Ltd | Construction | 2021 |
| Connxess Ltd | Administrative & support | 2019 |
| Conochem 97 Limited | Construction | 2002 |
| Conro & Sons Limited | Construction | 2017 |
| Conscious Awareness Music Ltd | Information & communication | 2025 |
| Conscious Care Group Ltd | Health & social care | 2025 |
| Construct IT Building Limited | Construction | 2023 |
| Construction Digging Ltd | Construction | 2026 |
| Construction Wise Consultancy Ltd | Professional & scientific | 2019 |
| Construction Work Services (CWS) Ltd | Construction | 2018 |
| Consult PR & Marketing Limited | Professional & scientific | 2010 |
| Consultancy and Growth Partnership Limited | Professional & scientific | 2022 |
| Consulting Well Ltd | Health & social care | 2020 |
| Consummate Care (UK) Ltd | Health & social care | 2009 |
| Consummate Care Services Limited | Health & social care | 2026 |
| Contact Business Finance Limited | Financial services | 2019 |
| Content Publishers Group Ltd | Information & communication | 2026 |
| Continuate Resourcing Limited | Administrative & support | 2022 |
| Contored Cosmetics UK Ltd | Other services | 2022 |
| Contract Blinds and Curtains Solar Shadings Ltd | Manufacturing | 2019 |
| Controlsys Ltd | Professional & scientific | 2023 |
| Convenient Store Limited | Wholesale & retail | 2019 |
| Conveyors & Automation Limited | Manufacturing | 2009 |
| Convivial Leisure Limited | Hospitality | 2017 |
| Cookies N Cakes Ltd | Manufacturing | 2026 |
| Cooky Services Ltd | Professional & scientific | 2026 |
| Cool Creations Studio Ltd. | Wholesale & retail | 2017 |
| Cooler Water (UK) Ltd | Wholesale & retail | 2009 |
| Cooper Car Club Limited | Other services | 2001 |
| Cooper Cranes Limited | Extraterritorial | 2004 |
| Cooper Group UK Limited | Professional & scientific | 2006 |
| Cooper Land & Estates Ltd | Real estate | 2026 |
| Cooper Mobile Services Limited | Wholesale & retail | 2000 |
| Coopers Bodyworks Limited | Wholesale & retail | 2026 |
| Copacompounds Limited | Wholesale & retail | 2019 |
| Copes Consultants Limited | Professional & scientific | 2024 |
| Copper Beech Investments Limited | Real estate | 2023 |
| Copper Cloud Software Limited | Information & communication | 2020 |
| Copperleaf Estates Ltd | Real estate | 2023 |
| Coppers Bars Ltd | Hospitality | 2019 |
| Coppice Ecology Limited | Professional & scientific | 2023 |
| Copthorne Property Limited | Real estate | 2025 |
| Copywise Hub Limited | Information & communication | 2024 |
| COR Technology Consulting Ltd | Information & communication | 2015 |
| Coral Reefs Ltd | Wholesale & retail | 2021 |