| Cancerwise | Health & social care | 1984 |
| Canute Cottages Ltd. | Real estate | 2002 |
| Capden Ltd | Professional & scientific | 2005 |
| Capozzi Health Ltd | Health & social care | 2026 |
| Capra AI Ltd | Information & communication | 2025 |
| Captain Charles Currey Limited | Administrative & support | 1951 |
| Captimax Sports Media Limited | Manufacturing | 2001 |
| Capture the Future Limited | Information & communication | 2018 |
| Carapace Limited | Information & communication | 2010 |
| Caravan GAS & Boat Services Limited | Other services | 2010 |
| Carbinium Engineering Limited | Manufacturing | 2015 |
| Carbon -VE Limited | Professional & scientific | 2022 |
| Carbon Solutions Group Ltd | Professional & scientific | 2024 |
| Carbon Solutions Holdings Ltd | Financial services | 2021 |
| Carbon Solutions Limited | Construction | 2014 |
| Carbon Zero Brokers Ltd | Professional & scientific | 2023 |
| Care and Services Ltd | Health & social care | 2024 |
| Careline 24 Ltd | Administrative & support | 2023 |
| Cargobay Properties Limited | Real estate | 1995 |
| Caring Hearts Homecare Ltd | Health & social care | 2020 |
| Carlines Secure Car Storage Ltd | Transport & logistics | 2025 |
| Caroline Daniel Consulting Ltd | Administrative & support | 2021 |
| Caroline Hunter PR Limited | Professional & scientific | 2017 |
| Caroline's Dairy LLP | | 2008 |
| Caromao Ltd | Professional & scientific | 2017 |
| Carpe Diem Property Holdings Limited | Construction | 2021 |
| Carpe Diem Property II Limited | Construction | 2017 |
| Carpentry Conversions Ltd | Construction | 2011 |
| Carrera Design & Draughting Limited | Professional & scientific | 1984 |
| Carriages Entertainment Limited | Administrative & support | 2026 |
| Carte Blanche Retail Limited | Information & communication | 2013 |
| Carte Blanche Licensing Limited | Professional & scientific | 1988 |
| Carters Lodge Farm Limited | Agriculture & fishing | 2010 |
| Cartref RTM Company Limited | Households | 2004 |
| CAS Properties Ltd | Real estate | 2019 |
| Caspia Consulting Limited | Professional & scientific | 2012 |
| Cassia Letchworth Ltd | Arts & recreation | 2022 |
| Cassius Holdings (Sussex) Ltd | Financial services | 2024 |
| Cassius Properties (Sussex) Ltd | Real estate | 2023 |
| Cast Iron Brown Ltd | Manufacturing | 2023 |
| Castell NC Ltd | Professional & scientific | 2022 |
| Castercliffe Ltd | Administrative & support | 2018 |
| Castle Driveways Limited | Construction | 2020 |
| Castle LGV Training Ltd | Education | 2019 |
| Castlecap Developments Limited | Real estate | 2009 |
| Castlecap Facilities Management Limited | Professional & scientific | 2018 |
| Castlecap Investments (WWP) Limited | Construction | 2016 |
| Castlecap Investments Five Limited | Real estate | 2014 |
| Castlecap Investments Four Limited | Real estate | 2014 |
| Castlecap Investments Limited | Other services | 2011 |
| Castlecap Investments Management Limited | Construction | 2014 |
| Castlecap Investments One Limited | Real estate | 2013 |
| Castlecap Investments Three Limited | Real estate | 2014 |
| Castlecap Investments Two Limited | Real estate | 2014 |
| Castlecap Residential One Limited | Real estate | 2013 |
| Catalyst Software Development Limited | Information & communication | 2024 |
| Catarina Martins Limited | Administrative & support | 2026 |
| Catfish Productions Ltd | Arts & recreation | 2024 |
| Cathedral Garage Limited | Wholesale & retail | 2003 |
| Cathedral Gardeners Ltd | Administrative & support | 2019 |
| Cathedral Homes (Chichester) Ltd | Real estate | 2021 |
| Cathedral Property Chichester Ltd | Real estate | 2025 |
| Cathedral Signs Limited | Information & communication | 2006 |
| Cathedral Wealth Management Limited | Financial services | 2014 |
| Cattledog Limited | Arts & recreation | 2016 |
| Cattledog Properties Limited | Real estate | 2017 |
| Cattlemarket Hub Ltd | Real estate | 2023 |
| CB Property Group Ltd | Real estate | 2021 |
| CBC Holdco Limited | Manufacturing | 2021 |
| CBS Sports Limited | Arts & recreation | 2022 |
| CC Developments (Southern) Limited | Other services | 2019 |
| Cc's OUT of School Limited | Health & social care | 2014 |
| CC1 Group Ltd | Hospitality | 2025 |
| CC8 Limited | Arts & recreation | 2023 |
| Ccol Holdings Limited | Financial services | 2022 |
| Ccol Properties Limited | Real estate | 2021 |
| Ccpsy Limited | Health & social care | 2020 |
| CCS2003 Limited | Arts & recreation | 2024 |
| Ccws Holdings Limited | Financial services | 2015 |
| Ccws Interiors Ltd | Construction | 2014 |
| Ccws Ltd | Construction | 2005 |
| Cdqs Ltd | Professional & scientific | 2023 |
| CEC Solutions Ltd | Professional & scientific | 2019 |
| Cedar Field Ltd | Real estate | 2025 |
| Cedar House (Monkton Street) Management Company Limited | Professional & scientific | 1999 |
| Cedar Valley Construction Limited | Construction | 2025 |
| Cedars Evington Limited | Hospitality | 2025 |
| CEF Maintenance Services Ltd | Professional & scientific | 2022 |
| Celebration Balloons 4 YOU Ltd | Arts & recreation | 2009 |
| Celladore Ltd | Hospitality | 2021 |
| Central Crown Properties Limited | Households | 1998 |
| Centre for Emotional Development Ltd | Health & social care | 2005 |
| Centre for ISO9000 Limited | Professional & scientific | 2006 |
| Centurion Cars Ltd | Transport & logistics | 2025 |
| Centurion Estate Planning Group Ltd | Professional & scientific | 2022 |
| Century 21 Security Limited | Administrative & support | 2000 |
| Century 21 Systems Limited | Information & communication | 2018 |
| Century House Brighton Limited | Real estate | 2019 |
| CFO Solutions Limited | Professional & scientific | 2003 |
| CFT Enterprises Limited | Hospitality | 2008 |