| Complete Property Services South East Ltd | Construction | 2017 |
| Complete Roofing Services Ltd | Construction | 2023 |
| Complete Smart Home Solutions Ltd | Construction | 2020 |
| Complete Strength Limited | Wholesale & retail | 2019 |
| Completely Carpets Limited | Construction | 2019 |
| Complex Waste Solutions Ltd. | Water & waste | 2025 |
| Compliant Surface Finishing Ltd | Manufacturing | 2021 |
| Complymatic Limited | Financial services | 2015 |
| Compuqaz Ltd | Information & communication | 2026 |
| Compx Limited | Construction | 2015 |
| Conack Homes (Midlands) Limited | Construction | 1994 |
| Conceiveit Ltd | Information & communication | 2012 |
| Concept Car Storage Ltd | Transport & logistics | 2023 |
| Concept Estates (Southern) Limited | Construction | 2017 |
| Concept Roofing Ltd | Construction | 2020 |
| Conceptual Audio Equipment Limited | Extraterritorial | 2011 |
| Concert Pitch Music Ltd | Manufacturing | 2018 |
| Concord Motors Limited | Wholesale & retail | 2025 |
| Concordia International Forwarding Limited | Transport & logistics | 1978 |
| Concordian Limited | Construction | 2019 |
| Concrete Cutters Limited | Construction | 2011 |
| Conebar Kerry Limited | Real estate | 2024 |
| Conex Fire Protection Limited | Construction | 2024 |
| Conex Limited | Construction | 2015 |
| Conform Limited | Extraterritorial | 1998 |
| Congreve Project Services Limited | Professional & scientific | 2022 |
| Conifer Court (Ashford) Residents Management Limited | Households | 1989 |
| Conker Consulting Limited | Professional & scientific | 2019 |
| Conker Estate Ltd | Real estate | 2020 |
| Connect 10 Estate Management Company Limited | Real estate | 2008 |
| Connect Furniture Installations Limited | Construction | 2007 |
| Connective Networks Ltd. | Information & communication | 2019 |
| Connoco Armstrong Ltd | Construction | 2014 |
| Connoco Asset Management Ltd | Financial services | 2014 |
| Connoco Services Limited | Information & communication | 2004 |
| Connoisseur Conferences 4000 Limited | Administrative & support | 2000 |
| Consero Ltd | Administrative & support | 2019 |
| Consilium Training and Support Ltd | Administrative & support | 2023 |
| Consolidated Hub Developments Ltd | Professional & scientific | 2014 |
| Consolidated Wines Limited | Wholesale & retail | 2018 |
| Constant Recruitment Limited | Administrative & support | 2012 |
| Construction and Management Services Limited | Professional & scientific | 2001 |
| Construction Design Studio Limited | Construction | 2015 |
| Construction Project Solutions Ltd | Administrative & support | 2014 |
| Construction Storm Ltd | Information & communication | 2024 |
| Consular Consultants Limited | Other services | 1982 |
| Consult HR Recruitment Limited | Professional & scientific | 2005 |
| Consult KW Ltd | Professional & scientific | 2011 |
| Consult South East Limited | Professional & scientific | 2023 |
| Contamaway Limited | Extraterritorial | 2002 |
| Contemporary Cottages Ltd | Real estate | 2023 |
| Contemporary Pubs Holdings Limited | Professional & scientific | 2023 |
| Contemporary Pubs Ltd | Hospitality | 2019 |
| Content Club Consulting Ltd | Information & communication | 2024 |
| Continuity Electrical Ltd | Construction | 2014 |
| Continuity Strategy Ltd | Professional & scientific | 2021 |
| Continuous Improvement Squared Limited | Professional & scientific | 2015 |
| Contract Intelligence Ltd. | Information & communication | 2015 |
| Contract Ventilation Services Ltd | Construction | 2001 |
| Controlled Air Services Limited | Administrative & support | 2009 |
| Controlled Atmosphere Services Ltd | Manufacturing | 2022 |
| Convergence Limited | Information & communication | 2023 |
| Convertini & Co Ltd | Hospitality | 2011 |
| Convex Mesh Ltd | Professional & scientific | 2016 |
| Cooluse Limited | Information & communication | 1998 |
| Coombes Cars Ltd | Transport & logistics | 2023 |
| Cooper Broadcast Services Limited | Information & communication | 2020 |
| Cope (Kent) Ltd | Hospitality | 2018 |
| Copier Systems South East Ltd | Wholesale & retail | 2021 |
| Copper and Oak Renovations Ltd | Construction | 2025 |
| Copperoak Construction Ltd | Manufacturing | 2018 |
| Coppertop Heating Ltd | Construction | 2020 |
| Coppins Limited | Financial services | 2020 |
| Copsehall Investments Limited | Real estate | 2021 |
| COR1 Management Services Limited | Administrative & support | 2014 |
| Coral & INK Limited | Wholesale & retail | 2022 |
| Corballon Limited | Construction | 1983 |
| Cordate Real Estates Limited | Real estate | 2021 |
| Cordes Horticultural Limited | Administrative & support | 2016 |
| Core Belief Natural Ltd | Wholesale & retail | 2025 |
| Core Carpentry Kent Ltd | Manufacturing | 2024 |
| Core Catering Services Ltd | Manufacturing | 2024 |
| Core Equestrian Physiotherapy Ltd | Professional & scientific | 2015 |
| Core Personal Training Studio Limited | Arts & recreation | 2020 |
| Core Qualities Ltd | Real estate | 2021 |
| Core Vitality Ltd | Public administration | 2026 |
| Coregan Limited | Information & communication | 2005 |
| Corfield Housing Limited | Real estate | 2019 |
| Coriante Construction Ltd | Construction | 2015 |
| Cork & Capture Ltd | Professional & scientific | 2025 |
| Cornershop Convenience Store Ltd | Wholesale & retail | 2026 |
| Corona Investments Limited | Real estate | 2000 |
| Corporate Resources Limited | Professional & scientific | 2008 |
| Corpstar Investments Limited | Information & communication | 1990 |
| Cortayne House (Ashford) Management Co. Ltd. | Extraterritorial | 1989 |
| Corylus Ecology Limited | Administrative & support | 2004 |
| Coskun Limited | Information & communication | 2022 |
| Cosmic Soul Wellness Ltd | Health & social care | 2025 |
| Cosmo 247 Ltd | Wholesale & retail | 2022 |
| Cosstick Property Services Ltd | Construction | 2024 |