| CNN Training Consultants Limited | Professional & scientific | 2015 |
| Cnzhs Limited | Hospitality | 2019 |
| Co - Vertec Limited | Manufacturing | 1992 |
| Coachspark Limited | Information & communication | 2025 |
| Coarsa Ltd | Health & social care | 2022 |
| Coast & Country Mortgages Limited | Financial services | 2026 |
| Coast Conservatories Limited | Construction | 2020 |
| Coast Performance Yacht Coatings Ltd | Manufacturing | 2022 |
| Coastal Forge Farriery Ltd | Agriculture & fishing | 2026 |
| Coastal Haven Group Limited | Real estate | 2025 |
| Coastal Haven Projects Limited | Real estate | 2025 |
| Coastal Haven Residences Limited | Real estate | 2025 |
| Coastal Homecare (Hove) Limited | Administrative & support | 2013 |
| Coastal Preservation Services Limited | Administrative & support | 2003 |
| Coastal Transport Site Services Limited | Water & waste | 2002 |
| Coastline Carpentry & Building Limited | Construction | 2006 |
| Cobra Precision Engineering Holdings Limited | Financial services | 2018 |
| Cobra Precision Engineering Limited | Manufacturing | 1989 |
| Cociloco Limited | Transport & logistics | 2020 |
| Coco's Hair and Beauty Salon Limited | Other services | 2019 |
| Coconnecta Ltd | Information & communication | 2025 |
| Cocos Coffee Shop Limited | Hospitality | 2025 |
| Code Nutrition Limited | Wholesale & retail | 2025 |
| Code Zero Marine Ltd | Manufacturing | 2025 |
| Coded Unknown Ltd | Information & communication | 2020 |
| Codesure Limited | Information & communication | 2019 |
| Coepilot Ltd | Transport & logistics | 2020 |
| Coffeeville UK Limited | Hospitality | 2026 |
| Cogent Land 2 Limited | Professional & scientific | 2023 |
| Cogger's Candys Limited | Hospitality | 2019 |
| Cogni Digital Ltd | Information & communication | 2016 |
| Cohesive Systems Ltd | Professional & scientific | 2023 |
| Cohman Scaffolding Ltd | Construction | 2020 |
| Coinaugur Ltd | Information & communication | 2026 |
| Cole Legacy Group Limited | Professional & scientific | 2025 |
| Coleman Building & Carpentry Ltd | Construction | 2026 |
| Coles Imaging Limited | Health & social care | 2024 |
| Collectively Global Ltd | Professional & scientific | 2024 |
| Collectivism Ltd | Other services | 2025 |
| Collectors Nexus Limited | Wholesale & retail | 2025 |
| Colleqt Group Limited | Administrative & support | 2021 |
| Collins Consultancy Services Ltd | Professional & scientific | 2023 |
| Collins Inter Security Limited | Real estate | 2021 |
| Collinsconnectdata Ltd | Construction | 2020 |
| Colourama Designs Limited | Wholesale & retail | 1998 |
| Colwell Bay Developments Limited | Construction | 2017 |
| Comedy Under the Stars Limited | Arts & recreation | 2021 |
| Comerplat Ltd | Wholesale & retail | 2022 |
| Comic Innovations Ltd | Professional & scientific | 2024 |
| Commercial Auctions Ltd | Wholesale & retail | 2019 |
| Community Childcare Centres | Education | 2001 |
| Comotion Global Limited | Administrative & support | 2014 |
| Comp Deck UK Limited | Wholesale & retail | 2020 |
| Compact Living Limited | Real estate | 2016 |
| Company Law Service & Administration Limited | Administrative & support | 2023 |
| Compass B2B Ltd | Financial services | 2009 |
| Compass Financial Planning Limited | Financial services | 2013 |
| Compass Homecare Ltd | Health & social care | 2018 |
| Complete Carpentry Southern Limited | Construction | 2022 |
| Complete Environment Services Limited | Construction | 2005 |
| Complete Property Services & SON Ltd | Construction | 2024 |
| Complete Site Surveys Ltd | Construction | 2025 |
| Complex Homecare Connect Limited | Health & social care | 2024 |
| Compton (Petersfield) Management Limited | Households | 2009 |
| Compton Care Limited | Extraterritorial | 2008 |
| Computer Communications (Holdings) Limited | Information & communication | 1999 |
| Computer Communications Limited | Information & communication | 1973 |
| Computer Doctor Services Limited | Information & communication | 2024 |
| Concept Holdings Limited | Professional & scientific | 2016 |
| Conjuring Reinvention Limited | Administrative & support | 2019 |
| Connected Cups Limited | Wholesale & retail | 2019 |
| Connection Timber Buildings Ltd | Construction | 2024 |
| Connexx Ltd | Construction | 2015 |
| Consalium Limited | Construction | 2011 |
| Construct Projects Ltd | Construction | 2022 |
| Construction Property Maintenance Services Limited | Construction | 2001 |
| CONSULT4BUSINESS Ltd | Professional & scientific | 2020 |
| Consultegg Limited | Professional & scientific | 2013 |
| Consultistry Ltd | Professional & scientific | 2015 |
| Contemplation Home Care Limited | Health & social care | 2007 |
| Content Central Limited | Information & communication | 2025 |
| CONTENT360 Limited | Information & communication | 2016 |
| Contract Services WR Limited | Administrative & support | 2021 |
| Contrafox Ltd | Extraterritorial | 2019 |
| Control and Automation Limited | Professional & scientific | 1990 |
| Control Risk Solutions Ltd | Administrative & support | 2020 |
| Convent Court Management Limited | Households | 1992 |
| Conway Rail & Construction Ltd | Construction | 2026 |
| Conway Rail Limited | Construction | 2015 |
| Conxim Limited | Construction | 2017 |
| Cookc Limited | Manufacturing | 2014 |
| Cookson Design Ltd | Professional & scientific | 2013 |
| Cool Cars South Coast Limited | Wholesale & retail | 2020 |
| Cool Rivers Media Ltd. | Extraterritorial | 2023 |
| Cooper Landmark Limited | Real estate | 2021 |
| Cooper Reed Ltd | Administrative & support | 2009 |
| Cooper's Agri Ltd | Agriculture & fishing | 2023 |
| Coopers Building Company Limited | Construction | 2017 |
| Coopers Drives & Controls Limited | Manufacturing | 1995 |
| Coopers Fire Limited | Manufacturing | 1986 |