| Continental Trade and Commodity Services Limited | Wholesale & retail | 1977 |
| Convenience First Express Limited | Wholesale & retail | 2021 |
| Cooper Stevens Headwear Limited | Wholesale & retail | 2013 |
| Cope&Lewis Limited | Professional & scientific | 2024 |
| Copers Grange Management Company Limited | Households | 2006 |
| Copia Metals Limited | Water & waste | 2017 |
| Copper FOX Press Limited | Information & communication | 2025 |
| Corado Hill Limited | Real estate | 2017 |
| Coral Sea Limited | Hospitality | 2019 |
| Corato Services Ltd | Health & social care | 2026 |
| Corbett Property Ltd | Real estate | 2014 |
| Core FS Limited | Financial services | 2008 |
| Cornerstone Inventure Ltd | Other services | 2021 |
| Cornerstone Properties Management Ltd | Real estate | 2025 |
| Cornerstone Royale Ltd | Real estate | 2025 |
| Cornwall 603 Ltd | Real estate | 2018 |
| Cornwall 701 Ltd | Real estate | 2018 |
| Corp-Direct Consulting Limited | Administrative & support | 2010 |
| Corporate Collaborations Limited | Professional & scientific | 2010 |
| Corporate Events (UK) Limited | Arts & recreation | 2000 |
| Correct Window & Door Installations Ltd | Construction | 2019 |
| Correct Window & Door Repairs Limited | Construction | 2019 |
| Cosa Construction Ltd | Construction | 2018 |
| Cosbuildservices Ltd | Construction | 2025 |
| Cosmic Pilates Limited | Wholesale & retail | 2025 |
| Cosmos Cleaning Services Limited | Administrative & support | 2024 |
| Cosy Maison Investor Ltd | Real estate | 2022 |
| Cotmandene Synergy Limited | Administrative & support | 2025 |
| Cottage Farms Holdings Limited | Financial services | 2023 |
| Cottage Farms Limited | Agriculture & fishing | 2008 |
| Coules Accounting and Tax Services Ltd | Professional & scientific | 2019 |
| Coulson Media Computers Ltd | Other services | 2022 |
| Countryside Lettings Limited | Real estate | 2010 |
| Court Road Supermarket Ltd | Wholesale & retail | 2025 |
| Courteney Jade Ltd | Professional & scientific | 2025 |
| Courtesy Kitchens and Bathrooms Ltd | Other services | 2016 |
| Covenant Homes Ltd | Real estate | 2024 |
| Coveta Limited | Real estate | 2019 |
| Covridge (UK) Ltd | Financial services | 2026 |
| Cpbs London Ltd | Extraterritorial | 2025 |
| Cpcg Ltd | Real estate | 2022 |
| CPE Rigging Ltd | Construction | 2024 |
| CR Enzyme Products Limited | Manufacturing | 2025 |
| Craft & Build Ltd | Construction | 2025 |
| Craft Building Contractors Limited | Construction | 2014 |
| Craft Construction (S.E.) Limited | Construction | 2010 |
| Craig Minto Heartwork Ltd | Health & social care | 2015 |
| Crancourt Management Company Limited | Households | 1987 |
| Cranfield Capital Assets Limited | Professional & scientific | 2023 |
| Craven Pierce Limited | Construction | 2024 |
| Cray Music Publishing Limited | Information & communication | 2024 |
| Cray Valley Communications Limited | Information & communication | 1996 |
| Cray Valley Construction Ltd | Construction | 2020 |
| Cray Valley Property Services Limited | Real estate | 2017 |
| CRE Electrical Ltd | Construction | 2026 |
| CRE8 International Group Ltd | Other services | 2018 |
| Crease Release Ltd | Households | 2024 |
| Createch Academies Ltd | Information & communication | 2017 |
| Creative and Neuro-Diverse Innovations (Candi) Community Interest Company | Hospitality | 2023 |
| Creative Signs Charlton Limited | Manufacturing | 2023 |
| Creative Soul Journeys Limited | Health & social care | 2022 |
| Creds Technologies Ltd | Professional & scientific | 2024 |
| Creo Bloom Ltd | Other services | 2025 |
| Creo World Ltd | Other services | 2023 |
| Cresada Limited | Professional & scientific | 2023 |
| Crescendo Technologies Limited | Financial services | 2020 |
| Cresta Property Services Limited | Real estate | 2024 |
| CRG Carpentry & Ceilings Ltd | Manufacturing | 2024 |
| CRG Construction & Development Ltd | Construction | 2024 |
| CRG Decorations Ltd | Construction | 2024 |
| CRG Electrical Ltd | Construction | 2024 |
| Crime Harms Reduction Team Ltd | Professional & scientific | 2018 |
| CRN Investment Ltd | Real estate | 2024 |
| Croager Consulting Ltd | Professional & scientific | 2025 |
| Crofton House Management Limited | Households | 1986 |
| Crofton Pharmacy Ltd | Wholesale & retail | 2014 |
| Crofton Property Limited | Real estate | 2024 |
| Crofton Services Limited | Administrative & support | 2016 |
| Cromer Limited | Wholesale & retail | 2005 |
| Croopard Ltd | Wholesale & retail | 2024 |
| Cross and Warren Enterprises Limited | Real estate | 2022 |
| Cross Lettings (London) Limited | Real estate | 2012 |
| Cross Letts Enterprises Limited | Real estate | 2011 |
| Cross Letts Limited | Administrative & support | 2010 |
| Cross-Town Consulting Limited | Manufacturing | 2021 |
| Crossbridge Services Limited | Professional & scientific | 2016 |
| Crossfit Orpington Ltd | Arts & recreation | 2022 |
| Crowie Developments Ltd | Construction | 2023 |
| Crown Developments Group Ltd | Construction | 2024 |
| Crowne Productions Limited | Arts & recreation | 2020 |
| Crownmi Ltd | Professional & scientific | 2019 |
| Croydon Calisthenics CIC | Arts & recreation | 2026 |
| Croydon Catholic Primary Schools Umbrella Trust | Education | 2015 |
| Crtr Racing Limited | Administrative & support | 2023 |
| Crucible Biotechnologies Limited | Manufacturing | 2026 |
| Cruickshank Plumbing & Heating Limited | Construction | 2015 |
| Cruickshank Properties Ltd | Real estate | 2018 |
| Crystal COD Limited | Hospitality | 2018 |
| Crystal Property Collective Ltd | Real estate | 2026 |
| CSA Property Management Limited | Transport & logistics | 2021 |