| Charlie Clover Racing Ltd | Arts & recreation | 2024 |
| Charlie Fellowes Racing Limited | Arts & recreation | 2016 |
| Charlography Ltd | Information & communication | 2025 |
| Charlotte Lamont Therapy Limited | Health & social care | 2021 |
| Charmstar Cambridge Limited | Construction | 2005 |
| Checkstress Limited | Professional & scientific | 2005 |
| Cheeky Sams @ Ltd | Hospitality | 2021 |
| Chelsea Bidco Limited | Financial services | 2021 |
| Chelsea Gardener Limited(The) | Professional & scientific | 1985 |
| Chelsea Holdco Limited | Financial services | 2023 |
| Chelsea Midco 1 Limited | Financial services | 2022 |
| Chelsea Midco 2 Limited | Financial services | 2021 |
| Chelsea Midco 3 Limited | Financial services | 2022 |
| Chelsea Thoroughbreds Limited | Arts & recreation | 2014 |
| Chelsteen Homes (Cheveley Road) Management Company Limited | Households | 1993 |
| Chesnoid Limited | Other services | 2015 |
| Cheveley Community Group CIC | Health & social care | 2023 |
| Cheveley Farming Limited | Extraterritorial | 1985 |
| Cheveley Farms (NO.2) Limited | Extraterritorial | 2003 |
| Cheveley Farms Limited | Extraterritorial | 1976 |
| Cheveley Holdings Limited | Professional & scientific | 1971 |
| Cheveley Park Farms Limited | Agriculture & fishing | 2003 |
| Cheveley Park Stud Limited | Agriculture & fishing | 1975 |
| Chine Healthcare Solutions Limited | Health & social care | 2021 |
| Chukka.Africa Ltd | Wholesale & retail | 2024 |
| Ciax Clothes Ltd | Wholesale & retail | 2026 |
| Cigar Cigar Ltd. | Wholesale & retail | 2012 |
| Citywest Incorporated Limited | Other services | 2003 |
| Ciutas Ltd | Hospitality | 2019 |
| CJO Studio Ltd | Wholesale & retail | 2024 |
| Clare Maddicott Publications Ltd. | Information & communication | 2002 |
| Clarehaven Ltd | Arts & recreation | 2017 |
| Claris Dental Ltd | Health & social care | 2024 |
| Clarke Philips Limited | Real estate | 2013 |
| Classic Barber Newmarket Ltd | Other services | 2023 |
| Classic Equine Services Ltd | Wholesale & retail | 2015 |
| Claxton Thoroughbreds Limited | Arts & recreation | 2022 |
| Claydon Yield-O-Meter Limited | Manufacturing | 1981 |
| Clean Stitch Newmarket Limited | Other services | 2026 |
| Clenched Ltd | Real estate | 2026 |
| Cleveland House Stud Limited | Arts & recreation | 2014 |
| Clicks Bar & Grill Limited | Hospitality | 2016 |
| Climbing Walls Installation Ltd | Professional & scientific | 2018 |
| Clinical Systems Holdings Limited | Professional & scientific | 2006 |
| Clinical Systems Limited | Information & communication | 1988 |
| Clip Clop Day Nursery Ltd | Education | 2010 |
| CLO Holdings Ltd | Administrative & support | 2024 |
| Cloments Ltd | Wholesale & retail | 2024 |
| Clopton Developments Limited | Construction | 2018 |
| Clopton Estate Limited | Agriculture & fishing | 1995 |
| Clopton Hall Farms Limited | Agriculture & fishing | 1948 |
| Clopton Park Management Company Limited | Households | 2003 |
| Cloud 9 Scaffolding Solutions Ltd | Construction | 2021 |
| Cloud Interiors Limited | Financial services | 2023 |
| CLOUD247 Limited | Wholesale & retail | 2022 |
| CLOUD6 Caterer Limited | Hospitality | 2025 |
| CLOUD6 Construction Ltd | Construction | 2025 |
| Clubwm Limited | Hospitality | 2016 |
| Clue Ventures Ltd | Information & communication | 2025 |
| CM Seven Limited | Professional & scientific | 2013 |
| Cmac Fibrous Plastering Ltd | Manufacturing | 2022 |
| CMY Trade Ltd | Construction | 2025 |
| Coal Exchange Freehold Ltd | Extraterritorial | 2022 |
| Cognico Ltd | Information & communication | 2024 |
| Cogs & Marvel (UK) Ltd | Arts & recreation | 2021 |
| Colin Medlock Limited | Other services | 2003 |
| Collier Hospitality Ltd | Hospitality | 2024 |
| Collings Berry Media Ltd | Administrative & support | 2008 |
| Collington Racing Limited | Arts & recreation | 2015 |
| Colour Point Studio Ltd | Manufacturing | 2004 |
| Colourco Cambridge Limited | Construction | 2019 |
| Cometic Gaskets Limited | Wholesale & retail | 2000 |
| Commercial Cleaners Ltd | Administrative & support | 2015 |
| Conceptum Ltd | Construction | 2022 |
| Conexions Limited | Administrative & support | 2007 |
| Conker Interiors Limited | Professional & scientific | 2005 |
| Cool Cargo Limited | Extraterritorial | 1995 |
| Cooleraid Holdings Ltd | Financial services | 2021 |
| Cooleraid Ltd | Wholesale & retail | 1991 |
| Cooper Darwin Bloodstock Ltd | Arts & recreation | 2018 |
| Copley Research Limited | Information & communication | 2026 |
| Copping Electrical Services Limited | Construction | 2010 |
| Cornthrop Bloodstock Limited | Agriculture & fishing | 2018 |
| Cornwall Hideaways Limited | Real estate | 1998 |
| Corps Property Investments Ltd | Real estate | 2019 |
| Cosmetic Content Club Ltd | Professional & scientific | 2024 |
| Cottage & Co Bury ST Edmunds Ltd | Wholesale & retail | 2025 |
| Cottage & Co Holdings Ltd | Manufacturing | 2023 |
| Countrywide Property Services Limited | Administrative & support | 2016 |
| Countywide Decorators Limited | Construction | 2011 |
| Countywide East Anglia Limited | Construction | 2014 |
| CPA Cards UK Limited | Wholesale & retail | 2025 |
| CPM Consult Ltd | Professional & scientific | 2021 |
| Craig Beck Racing Limited | Wholesale & retail | 2007 |
| Craig Thomas Limited | Financial services | 2013 |
| Crash Cleaner Limited | Administrative & support | 2020 |
| Crawford Capital Advisors Limited | Financial services | 2021 |
| CRC Pest Control Limited | Wholesale & retail | 2004 |
| CRC Pest Products Ltd | Wholesale & retail | 2023 |
| CRE8VANTAGE Ltd | Professional & scientific | 2024 |