| Copperberg Summits Limited | Administrative & support | 2016 |
| Coppermill Property Limited | Households | 2021 |
| Copperwood Ltd | Real estate | 2021 |
| Copthorne Drive (Alfreton) Management Company Limited | Households | 2021 |
| Core CRE8TIVE Limited | Professional & scientific | 2025 |
| Coreco Group Limited | Financial services | 2009 |
| Coreco Lifetime Limited | Extraterritorial | 2009 |
| Coreco Partners LLP | | 2012 |
| Coreco Specialist Finance Limited | Financial services | 2009 |
| Corin Underwriting Limited | Financial services | 2016 |
| Corina's Team Cleaning Ltd | Administrative & support | 2019 |
| Corinthian Place Management Company Limited | Households | 2019 |
| Corker Consulting Limited | Professional & scientific | 2022 |
| Corporate Consultancy and Investments Limited | Administrative & support | 2021 |
| Corporate Organisation Performance Solutions Limited | Professional & scientific | 2026 |
| Corrios Ltd | Wholesale & retail | 2024 |
| Coster M.S. Limited | Other services | 2014 |
| Cosytime Ltd | Wholesale & retail | 2022 |
| Cottage Containers Ltd | Transport & logistics | 2026 |
| Cotton's Caring Cremations Limited | Other services | 2023 |
| Couno Office Solutions Limited | Manufacturing | 2021 |
| County Shutters & Doors Limited | Construction | 2010 |
| Courtlands Amenity Management Limited | Households | 1996 |
| Couz Barbers Ltd | Other services | 2024 |
| Cove Catering Limited | Hospitality | 2025 |
| COW Southend Limited | Hospitality | 2023 |
| Coyne GRP Limited | Construction | 2022 |
| CPL Electrical Limited | Construction | 2018 |
| Crafted Accounting Ltd. | Professional & scientific | 2023 |
| Craig Telecoms Limited | Information & communication | 2022 |
| Cranbrook Solicitors Ltd | Professional & scientific | 2006 |
| Cranfield Park Management Company Limited | Real estate | 1994 |
| Crave Bakery and Coffeehouses Ltd | Hospitality | 2024 |
| Craveskills Digital Academy Ltd | Education | 2024 |
| Create Bikes Ltd | Wholesale & retail | 2013 |
| Createo Ltd | Professional & scientific | 2020 |
| Creative Radiators Ltd | Wholesale & retail | 2016 |
| Creatures Great & Small (Grooming) Ltd | Administrative & support | 2008 |
| Creatures Great & Small Limited | Wholesale & retail | 2002 |
| Creevy's Ltd | Wholesale & retail | 2023 |
| Cresco Limited | Other services | 2023 |
| Crest Apartments (Ilfracombe) Limited | Hospitality | 2010 |
| CRH Business Administration Limited | Administrative & support | 2016 |
| Criso Services Ltd | Manufacturing | 2018 |
| Crochem Associates Ltd | Administrative & support | 2014 |
| Cromwell Classics Ltd | Wholesale & retail | 2024 |
| Cross Haven Construction Limited | Construction | 2017 |
| Crosslands Court Management Company Limited | Households | 2006 |
| Crosslink Consulting Limited | Information & communication | 2018 |
| Crown Fields (Chatham) Management Company Ltd | Real estate | 2019 |
| Crown Vocational Training Limited | Education | 2012 |
| Crown VT Holdings Ltd | Financial services | 2026 |
| Cryo-Med Ltd | Other services | 2021 |
| Cryptonym Consulting Limited | Information & communication | 2023 |
| Crystal Crab Designs Ltd | Education | 2022 |
| Crystal Kingdom Social Enterprise CIC | Education | 2020 |
| Crystalle Ltd | Arts & recreation | 2024 |
| CS Developments UK Limited | Real estate | 2005 |
| CS Skyline Freeholds Ltd | Real estate | 2020 |
| CS Skyline Ltd | Real estate | 2018 |
| CSA Building Services Limited | Construction | 2026 |
| CSE Residential Limited | Real estate | 2022 |
| CSI Fire Protection Ltd | Construction | 2020 |
| CSL Care Ltd | Health & social care | 2024 |
| CTK Consulting Limited | Information & communication | 2008 |
| CTW Cars That Work Limited | Wholesale & retail | 2024 |
| Cubco Commodities Ltd | Administrative & support | 2023 |
| Cubist Digital Ltd | Information & communication | 2012 |
| Cubixify Limited | Professional & scientific | 2025 |
| Cudworth Distribution Limited | Information & communication | 1995 |
| CUG Holdings Limited | Financial services | 2022 |
| Culinary Chefs & Deliveries Limited | Transport & logistics | 2021 |
| Culturally Aware Ltd | Professional & scientific | 2026 |
| Cumberland House (Southend) Limited | Real estate | 2017 |
| Cunningham Close 1960 Limited | Extraterritorial | 2014 |
| Curious JAM Productions Limited | Administrative & support | 2014 |
| Current Collective Limited | Professional & scientific | 2024 |
| Curveran Limited | Administrative & support | 2020 |
| Custom Build Developments Ltd | Construction | 2021 |
| Custom Connecting Ltd | Information & communication | 2024 |
| Customised Property Solutions Ltd | Real estate | 2018 |
| CUT U UP Hair Academy Ltd | Other services | 2021 |
| Cuts and Blades Limited | Other services | 2016 |
| CW Tutoring Limited | Education | 2019 |
| Cxrm Ltd | Information & communication | 2024 |
| Cyberific Ltd | Administrative & support | 2018 |
| Cybernet IT Ltd. | Information & communication | 2023 |
| Cyberpunk Studios Ltd | Information & communication | 2019 |
| Cyprus Restaurants Ltd | Hospitality | 2020 |
| D & G Office Equipment Limited | Administrative & support | 2006 |
| D & G Plumbing Limited | Construction | 2021 |
| D & R Specialist Transport Limited | Transport & logistics | 2016 |
| D & S Healthcare Limited | Health & social care | 2024 |
| D a T Tinstamp Limited | Manufacturing | 1978 |
| D F Clark Contractors Limited | Administrative & support | 2002 |
| D Gould Properties Limited | Real estate | 2019 |
| D J Meara Heating & Plumbing Ltd | Construction | 2013 |
| D Kerner Electrical Ltd | Construction | 2006 |
| D L Clark Ltd | Other services | 2012 |
| D M Electrical SVS UK Limited | Construction | 2014 |