| Carpentry Design & Build Ltd | Construction | 2017 |
| Carrington's Roofing Ltd | Construction | 2023 |
| Carringtons Building & Civil Engineering Limited | Construction | 2003 |
| CAS Services Ltd | Administrative & support | 2023 |
| Casa Medica Limited | Health & social care | 2021 |
| Casaque UK Limited | Wholesale & retail | 2006 |
| Casinos (UK) Ltd | Extraterritorial | 2005 |
| Castello Farms Ltd | Wholesale & retail | 2021 |
| Castelo Mundial Ltd | Professional & scientific | 2025 |
| Castile Accommodations Limited | Real estate | 2019 |
| Castle Agencies Ltd | Financial services | 2013 |
| Castle and Sons Property Rentals Limited | Real estate | 2021 |
| Castles Air Limited | Construction | 2019 |
| Caswallen Close Ltd | Households | 2022 |
| Caterham Cars Group Limited | Manufacturing | 2004 |
| Caterham Cars Ltd. | Manufacturing | 1974 |
| Caterham EVO Limited | Manufacturing | 2023 |
| Catersave Europe Limited | Hospitality | 2008 |
| Catford Brothers Ltd | Wholesale & retail | 2017 |
| Cathybezuidenhout Limited | Professional & scientific | 2022 |
| Caught on Camera Cctv Limited | Administrative & support | 2020 |
| Caupo Property Limited | Real estate | 2016 |
| Caveman Brewing Company Ltd | Manufacturing | 2012 |
| Cay-Ray Wellness Ltd | Other services | 2023 |
| Cazi Candle Ltd | Wholesale & retail | 2025 |
| Cazi Homes Ltd | Households | 2025 |
| Cazi Joinery Ltd | Construction | 2025 |
| Cazi Renovation Ltd | Construction | 2025 |
| CB Painting and Decorating Services Ltd | Construction | 2025 |
| CBC Glazing Ltd | Wholesale & retail | 2020 |
| CBM Motors Limited | Wholesale & retail | 2022 |
| CBN Construction Projects Ltd | Construction | 2022 |
| CC Construction Services Ltd | Construction | 2015 |
| CC Motors London Ltd | Wholesale & retail | 2025 |
| CC Staffing Ltd | Administrative & support | 2025 |
| CC32 Services Ltd | Information & communication | 2026 |
| Ccbeautyandlashes Ltd | Other services | 2019 |
| Ccevents Limited | Hospitality | 2019 |
| CCP Power Solution Ltd | Construction | 2026 |
| CD Supplies & Workwear Ltd | Other services | 2025 |
| CDC Refurbishing Limited | Construction | 2001 |
| Cddtech Ltd | Extraterritorial | 2021 |
| CDH Cleaning Services Ltd | Administrative & support | 2023 |
| Cdit Electrical Ltd | Construction | 2018 |
| CDL Scaffolding Ltd | Construction | 2016 |
| Cdta Ltd | Transport & logistics | 2015 |
| Ceaseless Care Limited | Health & social care | 2022 |
| Cebanu Tiling Ltd | Construction | 2023 |
| Cedar Blue Accountants Ltd. | Professional & scientific | 2015 |
| Cedarx Properties Limited | Construction | 2022 |
| Ceeport Limited | Agriculture & fishing | 2022 |
| Celeazm Limited | Public administration | 2018 |
| Celerboss Limited | Financial services | 2022 |
| Celestial Empire Ltd | Financial services | 2022 |
| Cemnik Limited | Health & social care | 2022 |
| Centaur Group Limited | Financial services | 2017 |
| Centaur Overland Travel Limited | Transport & logistics | 1975 |
| Centaur PH Limited | Real estate | 2024 |
| Center for Creative Leadership Ltd | Education | 2017 |
| Centigrade Fire Consultants Limited | Professional & scientific | 2011 |
| Central Acquisitions Limited | Real estate | 2023 |
| Central Architecture Ltd | Professional & scientific | 2022 |
| Central Event Hire Limited | Transport & logistics | 2015 |
| Central London Removals Ltd | Transport & logistics | 2020 |
| Central Oceans UK Limited | Transport & logistics | 2021 |
| Central Roofing & Building Ltd | Construction | 2019 |
| Centre for Inclusive Evaluation Limited | Professional & scientific | 2026 |
| Centre for Inclusive Research and Education CIC | Professional & scientific | 2025 |
| Centred Health Ltd | Health & social care | 2018 |
| Centred Solutions Consultancy Ltd | Administrative & support | 2009 |
| Centurion Contracts Limited | Professional & scientific | 1999 |
| CEO Exclusive Cars Ltd | Administrative & support | 2026 |
| Cerisier Catering Ltd | Hospitality | 2023 |
| Certax Accounting London Ltd | Professional & scientific | 2013 |
| Certified Business Solutions UK Ltd | Information & communication | 2023 |
| Certified Diamond Build Ltd | Construction | 2020 |
| CEU Riders Ltd | Transport & logistics | 2026 |
| Cezara Speed Limited | Transport & logistics | 2018 |
| CFC 0089 Limited | Professional & scientific | 2013 |
| CFD Modelling Limited | Public administration | 2025 |
| CG Studios Limited | Financial services | 2012 |
| Cgpm Ltd | Construction | 2006 |
| CGS Builders Ltd | Construction | 2015 |
| CH Construction and Maintenance Ltd | Construction | 2022 |
| Chadwell Heath (Property Investments) Limited | Real estate | 2000 |
| Chai Waste Services Ltd | Transport & logistics | 2025 |
| Chalice Court RTM Company Limited | Households | 2019 |
| Chalkmehmet Homes Ltd | Construction | 2025 |
| Cham Co Cleaning Ltd | Administrative & support | 2025 |
| Chambers Associates Ltd | Professional & scientific | 2015 |
| Chameleon Care Limited | Health & social care | 2003 |
| Chameleon Pictures Limited | Information & communication | 2004 |
| Champions Theatre Arts Ltd | Arts & recreation | 2021 |
| Chanda Investments Ltd | Real estate | 2025 |
| Chandler Roofing and Building Ltd | Construction | 2017 |
| Changing Practice Review Limited | Extraterritorial | 2022 |
| Channell Commercial Europe Ltd | Information & communication | 1993 |
| Channell Limited | Information & communication | 1967 |
| Chantilly Lace Holdings Limited | Financial services | 2017 |
| Chapel Mill Holdings Limited | Information & communication | 2011 |