| CC Health Care Limited | Health & social care | 2017 |
| CED Sales and Marketing Ltd | Wholesale & retail | 2007 |
| CENTER4TESTING Limited | Information & communication | 2013 |
| Ceylon Estates Ltd | Real estate | 2022 |
| CGP Electrical Ltd | Construction | 2025 |
| Chadwick Court Limited | Households | 2002 |
| Chafford Tutoring Hub Limited | Education | 2018 |
| Chainai Ltd | Professional & scientific | 2025 |
| Chalkwell Green Padel Ltd | Arts & recreation | 2025 |
| Chalkwell Green Properties Limited | Financial services | 2021 |
| Chalkwell Insurance Services Ltd | Administrative & support | 2012 |
| Chanby Ltd | Real estate | 2022 |
| Charcoal Earth Limited | Administrative & support | 2022 |
| Charlie Brownies Ltd | Wholesale & retail | 2018 |
| Chase Court Gardens Management (Southend on Sea) Limited | Households | 2001 |
| Chase Ventures Limited | Wholesale & retail | 2013 |
| Chat Automation Limited | Information & communication | 2023 |
| Chavenlab & Allied Products Ltd | Other services | 2022 |
| Checkmate Innovation Limited | Professional & scientific | 2019 |
| Cheema Industries Limited | Wholesale & retail | 2022 |
| Chef Accrington Limited | Hospitality | 2026 |
| Chef Andrew B Ltd | Hospitality | 2025 |
| Chef Rise Limited | Hospitality | 2020 |
| Chelham Decorating Contractors Ltd | Construction | 2025 |
| Chelt Management Limited | Real estate | 2025 |
| Cheong Restaurant Limited | Hospitality | 2025 |
| Cherry Gardens Estates Ltd | Real estate | 2026 |
| CHI Dulwich Limited | Hospitality | 2026 |
| CHI Oriental Limited | Hospitality | 2026 |
| Chinese Printing Limited | Information & communication | 2002 |
| Ching Ching Ltd | Hospitality | 2018 |
| Choice Strategy Limited | Administrative & support | 2022 |
| Chris Allnutt Rentals Ltd | Real estate | 2021 |
| Chris Box Audio Ltd | Information & communication | 2012 |
| Christ Culture UK | Other services | 2017 |
| Christian Housing Limited | Hospitality | 2016 |
| Chubby Cheeks Limited | Health & social care | 2026 |
| Chun HIN Company Limited | Hospitality | 2017 |
| Cinemora Studios Ltd | Professional & scientific | 2025 |
| CIT Enterprises Ltd | Professional & scientific | 2025 |
| Citybrick Project Limited | Construction | 2018 |
| Clarence's Armchair Holdings Ltd | Real estate | 2019 |
| Clarke Alliance Ltd | Information & communication | 2010 |
| Classic Building & Flooring Specialist Limited | Manufacturing | 2015 |
| Classic Holdings Europe PLC | Administrative & support | 2013 |
| Classic Vehicle Investments Limited | Administrative & support | 2013 |
| Claverley Freehold Co Ltd | Households | 2024 |
| Claverley Management Co Ltd | Households | 2017 |
| Clever Methods Ltd | Professional & scientific | 2008 |
| Cliffnorth Ltd | Real estate | 2025 |
| Cliffsea Ltd | Real estate | 2025 |
| Cliffside Estates Ltd | Real estate | 2023 |
| Cliffside Ltd | Real estate | 2017 |
| Cliffside Solutions Ltd | Real estate | 2017 |
| Clifftown Bar Co Ltd | Hospitality | 2025 |
| Clifftown Carpentry Limited | Manufacturing | 2022 |
| Cltl Ltd | Other services | 2020 |
| Club Moto London Ltd | Administrative & support | 2017 |
| Cmrd Telecoms Ltd | Information & communication | 2020 |
| CNR Shangrila Properties Ltd | Real estate | 2023 |
| Co-Heirs Properties Ltd | Real estate | 2025 |
| Coast Capture Air Limited | Wholesale & retail | 2018 |
| Coastline Management Limited | Households | 1989 |
| COG CN Limited | Administrative & support | 2011 |
| Collaborative Coaching Ltd | Administrative & support | 2025 |
| Collings Construction Limited | Construction | 2018 |
| Colonial World Foods (UK) Limited | Manufacturing | 2003 |
| Compete Tennis LLP | | 2009 |
| Complete Property Management Southend Ltd. | Real estate | 2011 |
| Computrust Limited | Information & communication | 2010 |
| Connectifit Limited | Administrative & support | 2021 |
| Connseb Properties Limited | Households | 2020 |
| Conseb Properties Limited | Construction | 2020 |
| Consort Services LC Limited | Health & social care | 2010 |
| Cooks Coaches Limited | Administrative & support | 2017 |
| Copyconscious Ltd | Professional & scientific | 2022 |
| Coral Garden Estates Ltd | Real estate | 2026 |
| Core Utility Services Ltd | Construction | 2018 |
| Corner Shop Films Ltd | Information & communication | 2026 |
| Corteo Ltd | Manufacturing | 2013 |
| Cottage Garden Mews Limited | Households | 2016 |
| Coughlan M&E Services Ltd | Construction | 2021 |
| Coull Surgery Ltd | Health & social care | 2012 |
| Cova Recruitment Ltd | Administrative & support | 2025 |
| CPC Building Service Limited | Households | 2023 |
| CPY & Co UK Limited | Administrative & support | 2017 |
| Crave Corner SS0 Limited | Hospitality | 2025 |
| Crazy Ryan Ltd | Arts & recreation | 2024 |
| Creation Aquatics Limited | Wholesale & retail | 2010 |
| Creations Brickwork Ltd | Construction | 2024 |
| Creed Marketing Ltd | Administrative & support | 2019 |
| Creekside Projects Limited | Professional & scientific | 2011 |
| Crispins RTM Company Limited | Households | 2004 |
| Crispy Fish Dish Limited | Hospitality | 2026 |
| Crosa Ltd | Hospitality | 2013 |
| Cross Suddell Limited | Transport & logistics | 2020 |
| Crowstone Court Westcliff Freehold Company Limited | Households | 2017 |
| Crunchy COD Limited | Hospitality | 2025 |
| Crunchy Kebab Ltd | Hospitality | 2025 |
| Crux C&E Limited | Construction | 2023 |