| Corvotech Limited | Professional & scientific | 2011 |
| Cosgrove Design and Build Limited | Construction | 2014 |
| Cosgrove Lettings Limited | Real estate | 2017 |
| Cosgrove Properties Limited | Extraterritorial | 2017 |
| Cosmelinks Ltd | Wholesale & retail | 2018 |
| Cosmetic Tattooing Training Ltd | Education | 2021 |
| Cosmic RC Ltd | Wholesale & retail | 2024 |
| Cosmo Care UK Ltd | Health & social care | 2013 |
| Cost Plan Consulting Limited | Professional & scientific | 2021 |
| Coster Consultancy Ltd | Health & social care | 2021 |
| Cosy Dream Home Limited | Real estate | 2021 |
| Cosy Holdings Ltd | Financial services | 2025 |
| Cosy LIVING4U Ltd | Financial services | 2023 |
| Cottis Investments Limited | Real estate | 2019 |
| Coua Ltd | Information & communication | 2026 |
| Coull Catering Company Ltd | Hospitality | 2025 |
| Count Ready Limited | Financial services | 2016 |
| Country Conferences Limited | Real estate | 2004 |
| Countryside Automation Limited | Administrative & support | 2008 |
| Countryside Communications Limited | Information & communication | 1998 |
| Countrywide Design and Construction Ltd | Construction | 1997 |
| Countrywide Home Improvements Limited | Construction | 2017 |
| Countrywide Surveyors Limited | Administrative & support | 1985 |
| Countrywide Vehicle Contracts Ltd | Financial services | 2008 |
| County and Urban Services Limited | Administrative & support | 2020 |
| County Estates (Essex) Limited | Real estate | 1998 |
| County Greens Ltd | Real estate | 2017 |
| County Hotel (Chelmsford) Limited | Professional & scientific | 2006 |
| County Hotel Essex Ltd | Professional & scientific | 2016 |
| County Linen Service Limited | Extraterritorial | 1985 |
| County Logistics Solutions Limited | Administrative & support | 2022 |
| County Mortgage Services Limited | Financial services | 2015 |
| County Plant Hire Solutions Limited | Administrative & support | 2022 |
| County Solutions Security Ltd | Administrative & support | 2025 |
| County Textile Solutions Limited | Other services | 2022 |
| County Washrooms Group Limited | Construction | 2018 |
| County Washrooms South Limited | Extraterritorial | 2026 |
| County Workwear Solutions Limited | Other services | 2022 |
| Course Foxtail Limited | Financial services | 2022 |
| Court Oak Holdings Limited | Real estate | 2021 |
| Courtkind Limited | Administrative & support | 1983 |
| Courtney Park Management Company Limited | Households | 1986 |
| Coverbeeny Limited | Wholesale & retail | 2025 |
| Covr Group Limited | Manufacturing | 2022 |
| COW Corner Consulting Limited | Professional & scientific | 2017 |
| Cowgum Limited | Manufacturing | 2022 |
| Cowling & Payne Limited | Real estate | 2003 |
| Cownet Limited | Manufacturing | 2023 |
| Cowrk Ltd | Information & communication | 2025 |
| Coyle's Construction London Ltd | Construction | 2019 |
| Coypondstudio Ltd | Wholesale & retail | 2026 |
| Cozororo PVT Ltd | Construction | 2019 |
| CP Construction Consultants LLP | | 2005 |
| CPB2016 Ltd | Professional & scientific | 2016 |
| CPE Chelmsford Limited | Construction | 2014 |
| CPH Sales Consultancy Limited | Other services | 2016 |
| CPS Auto Paint Limited | Wholesale & retail | 2012 |
| CR Education Support Limited | Education | 2022 |
| Craft-E LDN Ltd | Construction | 2026 |
| Craftsilver Limited | Real estate | 1994 |
| Craftsyn Ltd | Wholesale & retail | 2025 |
| Craig Gilbert Engineering Limited | Administrative & support | 2007 |
| Cranham Leisuresales Ltd | Administrative & support | 1995 |
| Crash Detectives Limited | Administrative & support | 2001 |
| Crawfords Group Holdings Ltd | Wholesale & retail | 2022 |
| Crawley Consultancy Ltd | Public administration | 2020 |
| CRC Manchester | Other services | 2019 |
| CRE8 Design Studios Limited | Professional & scientific | 2012 |
| Cream Beauty Limited | Other services | 2022 |
| Cream Beauty Nails Ltd | Other services | 2023 |
| Creative Chelmsford Ltd | Arts & recreation | 2015 |
| Creative Crave Limited | Professional & scientific | 2021 |
| Creative Edge Solustions Ltd | Professional & scientific | 2024 |
| Creative Engineering for Kids Ltd | Education | 2022 |
| Creative Idiots Limited | Education | 2024 |
| Creative Learning Systems Limited | Information & communication | 2011 |
| Creative Special Displays Ltd | Professional & scientific | 2019 |
| Creative Tools Limited | Information & communication | 2005 |
| Creative Visuals Collective Ltd | Information & communication | 2024 |
| Creator Homes Ltd | Real estate | 2025 |
| Crema Cafe Ltd | Hospitality | 2017 |
| Crephut Ltd | Wholesale & retail | 2015 |
| Crescent Farm Fresh Poultry (East Anglia) Limited | Wholesale & retail | 2005 |
| Cresland Ltd | Professional & scientific | 2018 |
| Cressing Maintenance Limited | Construction | 2014 |
| Crest and Bravo Estates Ltd | Real estate | 2025 |
| Crest Productions Limited | Extraterritorial | 2011 |
| Cretepave Plus Ltd | Construction | 2006 |
| Criblex Homes Limited | Real estate | 2023 |
| Cricket BAT Willow Limited | Extraterritorial | 2023 |
| Cricket Pitch LLP | | 2019 |
| Cris-Nicky Trans Ltd | Transport & logistics | 2016 |
| Crisp & Co Consultants Ltd | Professional & scientific | 2022 |
| Crisp Consultants Limited | Financial services | 2013 |
| Cristall Cleaning Service Ltd | Administrative & support | 2020 |
| Crlt Tattoo Limited | Other services | 2026 |
| CRM Change Consultants Limited | Professional & scientific | 2024 |
| CRO Media Ltd | Professional & scientific | 2019 |
| Croban Abodes Ltd | Real estate | 2022 |
| Croft Laver Ltd | Other services | 2023 |