| C & a Hardman Limited | Extraterritorial | 2004 |
| C & D Commercial Vehicle Sales Ltd | Wholesale & retail | 2006 |
| C & D Uniform Solutions Limited | Wholesale & retail | 1967 |
| C and L Motortech Ltd | Wholesale & retail | 2021 |
| C Fuller Limited | Administrative & support | 2005 |
| C Thornley Holdings Ltd | Financial services | 2024 |
| C. Anderson Contracts Limited | Wholesale & retail | 1990 |
| C. P. Oldman Builder Limited | Construction | 2004 |
| C.G.C. Limited | | 1991 |
| C.V.S. (Anglia) Limited | Wholesale & retail | 1987 |
| Cajon Technology Limited | Information & communication | 2024 |
| Camacho Properties Ltd | Real estate | 2025 |
| Cambridge Nanoceramix Limited | Professional & scientific | 2007 |
| Cambridge Nanolitic Limited | Professional & scientific | 2006 |
| Cape Contracts Scaffolding Limited | Construction | 2003 |
| Capitalsoft Ltd | Information & communication | 2023 |
| Caravel Limited | Professional & scientific | 2005 |
| Carbondetailsuk Ltd | Wholesale & retail | 2026 |
| CARECROSS24 Limited | Administrative & support | 2022 |
| Career Catalyst & Recruitment Ltd | Professional & scientific | 2025 |
| Caribbean Blinds (UK) Limited | Manufacturing | 1987 |
| Caring Hands Russia Limited | Health & social care | 1998 |
| Carlo Thomas Ltd | Real estate | 2023 |
| Carlton Hotels (Ipswich) Ltd | Hospitality | 2003 |
| Carousel Engineering Limited | | 1980 |
| Carrington Electrics Ltd | Construction | 2015 |
| Carter Pearl Limited | Financial services | 1986 |
| Cartpilot Limited | Administrative & support | 2025 |
| Castle Clothing Limited | Wholesale & retail | 1972 |
| Casual Temp Waiting Staff Ltd | Administrative & support | 2024 |
| Cbone Engineering Limited | Transport & logistics | 2002 |
| CD Friend & Sons Ltd | Wholesale & retail | 2007 |
| Central Garage,(Lowestoft).Limited | Real estate | 1954 |
| Centre for Climate Reporting Ltd | Information & communication | 2021 |
| Centric Primary Care Management Limited | Professional & scientific | 2022 |
| Centurion Technical Security Ltd | Information & communication | 2023 |
| Century Accounting Limited | Professional & scientific | 2006 |
| Ceylon Lettings Ltd | Real estate | 2021 |
| Chadfield Property Ltd. | Real estate | 2003 |
| Champkin Auto Repairs Limited | Wholesale & retail | 2004 |
| Changedeal Cartons Limited | | 1986 |
| Charin Limited | Wholesale & retail | 2017 |
| Charnarvind Limited | Real estate | 2021 |
| Chbates Limited | Professional & scientific | 2019 |
| Chef.Ease Ltd | Administrative & support | 2023 |
| Chefs Food Products Ltd | Manufacturing | 2018 |
| Chemystery Limited | Professional & scientific | 2002 |
| Cherwell Projects Ltd | Construction | 2012 |
| Chestnut Drive Claydon Management Company Limited | Households | 1989 |
| Cheveley Park Racing Stables Limited | Extraterritorial | 1975 |
| Cheveley Properties Limited | Real estate | 1999 |
| Chic Love Limited | Wholesale & retail | 2024 |
| Chicken Express Takeaway Ltd | Hospitality | 2021 |
| Chief Solutions Software Engineering Ltd | Information & communication | 2023 |
| Chieflift Limited | Professional & scientific | 1987 |
| Childcentre Limited | Real estate | 1986 |
| Chilton Place Stowmarket Limited | Households | 2017 |
| Chimney POT Property Ltd | Real estate | 2022 |
| Chris Newland Sales Agency Limited | Professional & scientific | 2008 |
| Christy & Norris Limited | Professional & scientific | 2002 |
| Christy Hunt (Agricultural) Limited | Professional & scientific | 1990 |
| Christy Turner Ltd | Manufacturing | 1968 |
| Church Motors (Kessingland) Limited | Wholesale & retail | 2007 |
| Cipher Core Limited | Information & communication | 2024 |
| Cipher Crystal Limited | Wholesale & retail | 2002 |
| Circleconnect Innovations Ltd | Information & communication | 2025 |
| Ckdglo Ltd | Wholesale & retail | 2019 |
| Claas Eastern Ltd | Wholesale & retail | 1994 |
| Claas Holdings Limited | Wholesale & retail | 1980 |
| Claas Manns Ltd | Wholesale & retail | 1997 |
| Claridge Investments Limited | Real estate | 1959 |
| Clarify AI Limited | Administrative & support | 2023 |
| Clawgleamdesigns Ltd | Wholesale & retail | 2025 |
| Clawtidelamps Ltd | Wholesale & retail | 2025 |
| Clean & Secure Ltd | Administrative & support | 2025 |
| Cleaning Technicians Limited | Other services | 1990 |
| Clements Superstore Ltd | Wholesale & retail | 2003 |
| Climax Molybdenum U.K. Limited | Manufacturing | 1940 |
| Cloud Cabin Limited | Information & communication | 2025 |
| Cloud Consult Services Ltd | Information & communication | 2019 |
| Club Orange Limited | Construction | 2017 |
| Coady Still Facades Ltd | Construction | 2025 |
| Coady Still Limited | Construction | 2011 |
| Coastal Pigs Limited | Agriculture & fishing | 2002 |
| Cobb-Lee's Limited | Manufacturing | 2002 |
| Cocksedge (Holdings) Limited | Construction | 2005 |
| Coding Studio Limited | Information & communication | 2022 |
| Codixera Limited | Information & communication | 2024 |
| Colchester Aquatics Limited | Wholesale & retail | 2005 |
| Colin Bayliss Props Services Limited | Information & communication | 2003 |
| Collen & Clare Limited | Wholesale & retail | 2003 |
| Colwyn Developments Limited | Real estate | 1985 |
| Colwyn Property & Land Limited | Real estate | 2004 |
| Commerciio Ltd | Real estate | 2019 |
| Complete Data Solutions Limited | Transport & logistics | 2002 |
| Comtho Limited | Wholesale & retail | 2024 |
| Concitatusone Limited | Real estate | 2025 |
| Consumer Africa Group Limited | Information & communication | 2024 |
| Consumer First Ltd | Real estate | 2022 |
| Continental Leaves & Beans Limited | Hospitality | 2007 |