| COOL4HEAT Solutions Ltd | Construction | 2024 |
| Coole Homes Limited | Real estate | 2020 |
| Coombes Cosmetics Ltd | Other services | 2019 |
| Coop Micro Bar Hedge END Ltd | Hospitality | 2025 |
| Coop Micro Bar Ringwood Ltd | Hospitality | 2025 |
| Coop Micro Bar Shirley Ltd | Hospitality | 2025 |
| Cooper Marine Advisors Limited | Administrative & support | 2016 |
| Cooper-Standard Automotive UK Sealing Limited | Professional & scientific | 1931 |
| Coops Home Improvements Ltd | Construction | 2025 |
| COP3 Ltd | Extraterritorial | 2022 |
| Copeland Travel Ltd | Administrative & support | 2024 |
| Copernic UK Limited | Financial services | 2009 |
| Copied Hall Holdings Ltd | Financial services | 2024 |
| Copied Hall Limited | Agriculture & fishing | 2016 |
| Coppa Gutta Limited | Extraterritorial | 2002 |
| Copper Beeches Management (Southampton) Limited | Real estate | 2005 |
| Copperplate Bradford Ltd | Construction | 2024 |
| Copperplate Developments Limited | Construction | 2022 |
| Coppice Grove Management Company Limited | Real estate | 2015 |
| Coppice View Management (Whiteley) Limited | Households | 1998 |
| Coppins Services Limited | Professional & scientific | 2017 |
| Coppitswood Investments Limited | Real estate | 2025 |
| Copse Estates Limited | Real estate | 2018 |
| Copse Hill Management 2008 Limited | Real estate | 2008 |
| Copythorne Community Cafe Ltd | Hospitality | 2022 |
| Copythorne Garage Limited | Wholesale & retail | 2007 |
| Corbyn Apartments Limited | Hospitality | 2014 |
| Cordial 4 Developments Limited | Administrative & support | 2014 |
| Cordial Enterprise Limited | Construction | 2019 |
| Cordula GB Servicing and Parts Ltd | Wholesale & retail | 2019 |
| Core Cleaning Solutions Ltd | Administrative & support | 2024 |
| Core CS Limited | Professional & scientific | 2024 |
| Core Environmental PLC | Wholesale & retail | 2017 |
| Core Flow Ltd | Wholesale & retail | 2020 |
| Core Flow SUP Ltd | Wholesale & retail | 2020 |
| Core GAS Safety Ltd | Education | 2019 |
| Core Investment Group Limited | Real estate | 2026 |
| Core Platforms Limited | Information & communication | 2017 |
| Core Property Solutions Limited | Construction | 2015 |
| Core SLN Ltd | Information & communication | 2018 |
| Core Software Solutions Group Limited | Information & communication | 2026 |
| Core Vision Build Ltd | Construction | 2025 |
| Core Vocational Training Limited | Education | 2018 |
| Corebuild (South) Ltd | Construction | 2026 |
| Corenet Technical Limited | Professional & scientific | 2007 |
| Corestone Limited | Wholesale & retail | 2015 |
| Coriander Lounge Southampton Limited | Hospitality | 2009 |
| Corinthian Mortgage Solutions Ltd | Financial services | 2013 |
| Cornelia Court Management Limited | Households | 1995 |
| Cornell Structures Ltd | Professional & scientific | 2006 |
| Cornerbusiness Limited | Transport & logistics | 2024 |
| Cornish & Kelly Enterprises Limited | Wholesale & retail | 2026 |
| Cornish & Kelly Ventures Limited | Construction | 2023 |
| Cornwall Boat Storage Ltd | Transport & logistics | 2022 |
| Corporate Energising Ltd | Professional & scientific | 2005 |
| Corporate Express Couriers Limited | Transport & logistics | 1999 |
| Corporate Office Services Limited | Other services | 2001 |
| Corporate Professional Services Limited | Real estate | 2020 |
| Corps Solutions Limited | Administrative & support | 2014 |
| Correct Contract Services Limited | Construction | 2007 |
| Corridor Cleaning Limited | Administrative & support | 2006 |
| Corsar Limited | Real estate | 2016 |
| Corsi Property Investments Ltd | Real estate | 2025 |
| Cortex Limited | Information & communication | 2004 |
| Cortha Limited | Professional & scientific | 2013 |
| Corylus Projects Limited | Construction | 2024 |
| Cosatu Gardeners Limited | Arts & recreation | 2020 |
| Cosens and Company,Limited | Energy | 1876 |
| Cosgrove Painting Contractors Limited | Construction | 2016 |
| Cosmic Resonance Ltd | Manufacturing | 2021 |
| Cossack Lane House (Winchester) Limited | Households | 1974 |
| Cossie & Co Ltd | Wholesale & retail | 2015 |
| Costa Cars Motor Ltd | Wholesale & retail | 2025 |
| Costel Trans Ltd | Transport & logistics | 2016 |
| Costello Orthodontics Limited | Health & social care | 2022 |
| Costeo Ltd | Wholesale & retail | 2025 |
| Costigan Science Ltd | Professional & scientific | 2025 |
| Cosy Cafe Place Ltd | Hospitality | 2024 |
| Cosy Glow Heating Limited | Construction | 2016 |
| Cosy Home Projects Ltd | Construction | 2024 |
| Cosy Property Solutions Ltd | Real estate | 2023 |
| Cosytail Ltd | Wholesale & retail | 2025 |
| Cotekmarine Ltd | Professional & scientific | 2014 |
| Cotterill Consulting Limited | Information & communication | 2011 |
| Cougar Limited | Energy | 1980 |
| Coulson Lifting Services Limited | Construction | 2014 |
| Counselling Education Academy Group Limited | Education | 2022 |
| Countisbury Limited | Hospitality | 1978 |
| Country Homes (Village Site) Ltd | Construction | 2013 |
| Country Inns (New Forest) Limited | Hospitality | 2015 |
| Country Inns (Southern) Limited | Hospitality | 2018 |
| County Accounting & Bookkeeping Limited | Professional & scientific | 2009 |
| County Ambulance Service Limited | Health & social care | 2014 |
| County Driveways and Drop Kerbs Ltd | Construction | 2026 |
| County Electricians Limited | Construction | 2013 |
| County Tree Care Limited | Agriculture & fishing | 2019 |
| Couriers 4U Limited | Transport & logistics | 2024 |
| Court Accounting Services Limited | Professional & scientific | 2003 |
| Court House Catering Limited | Hospitality | 2009 |
| Court Property Services Ltd | Construction | 2007 |