| Cartube Ltd | Wholesale & retail | 2026 |
| Carzana Interiors Limited | Other services | 2001 |
| Caspen Limited | Professional & scientific | 2004 |
| Casperaki Holdings (U.K.) Limited | Information & communication | 2012 |
| Cassleton Elliott & Co Limited | Administrative & support | 2006 |
| Casuite Ltd | Other services | 2025 |
| Catalindan Ltd | Manufacturing | 2026 |
| Cayuga Property Ltd | Real estate | 2025 |
| CBI Meetings Ltd. | Administrative & support | 2013 |
| CDH Recruitment Limited | Administrative & support | 2009 |
| Cdla Limited | Manufacturing | 2025 |
| Centripeta Limited | Professional & scientific | 2002 |
| Cguk Limited | Real estate | 2020 |
| Chapelwood Design & Joinery Limited | Manufacturing | 2025 |
| Chapter Carpentry Ltd | Construction | 2019 |
| Charisma 2 Gent's Hair Design Ltd | Other services | 2023 |
| Charles Clark & Co Limited | Hospitality | 2004 |
| Charmbeck Limited | Wholesale & retail | 1985 |
| Charterhouse Asset Management & Investments Limited | Extraterritorial | 2014 |
| Charterhouse Asset Management Limited | Extraterritorial | 2013 |
| Charterhouse Bexhill Assets Ltd | Real estate | 2020 |
| Charterhouse Bexhill Freehold Assets Ltd | Other services | 2023 |
| Charterhouse Property Holdings Limited | Financial services | 2015 |
| Charterhouse Solutions (South East) Ltd | Professional & scientific | 2015 |
| Chelsea Real Properties Ltd | Real estate | 2016 |
| Cherry PI Ltd | Professional & scientific | 2018 |
| Chickenhood Limited | Hospitality | 2023 |
| Child Centred Solutions Limited | Health & social care | 2010 |
| Chinasol Import Ltd | Wholesale & retail | 2003 |
| Chloeinspires Limited | Information & communication | 2023 |
| Chris Knott Insurance Consultants Limited | Financial services | 1993 |
| Christina Marie Marketing Consultancy Ltd | Information & communication | 2022 |
| Chromis Films Ltd | Information & communication | 2011 |
| Cipha Ltd | Arts & recreation | 2022 |
| Circadian Design Ltd | Arts & recreation | 2019 |
| CJ Bell Health & Safety Limited | Administrative & support | 2011 |
| CJ Johnson Ltd | Professional & scientific | 2025 |
| CKS Installations Limited | Construction | 2018 |
| Clarence Trading Ltd | Hospitality | 2017 |
| Clarity Commerce Limited | Information & communication | 1999 |
| Claritytoo Limited | Real estate | 2016 |
| Clark & Hanson Construction Services Ltd | Construction | 2022 |
| Class in a Glass Mobile Bar Ltd | Hospitality | 2020 |
| Clayton Management Ltd | Real estate | 2022 |
| Clayton Property South Ltd | Real estate | 2026 |
| Clean Cuisine Food Limited | Hospitality | 2024 |
| Clear Choice Exterior Cleaning Services Ltd | Administrative & support | 2024 |
| Cleared Wright Ltd | Real estate | 2023 |
| Cleric Limited | Extraterritorial | 2004 |
| Click Content Ltd | Administrative & support | 2023 |
| Cliff END Records Limited | Manufacturing | 2020 |
| Cliff END Taverns Ltd | Hospitality | 2022 |
| Clifford Hayles Limited | Construction | 2017 |
| Clipvalve Limited | Wholesale & retail | 1981 |
| Clive Attrell Limited | Wholesale & retail | 2014 |
| Clive Vale Nursery School Limited | Education | 2013 |
| Cloaked SIX Limited | Extraterritorial | 2018 |
| Cloud by Design Ltd | Information & communication | 2013 |
| Cloud Data Solutions Ltd | Information & communication | 2014 |
| Cloudit Accounting Limited | Extraterritorial | 2016 |
| Cloudsdale Limited | Professional & scientific | 2016 |
| Cmedics Ltd | Health & social care | 2025 |
| Cmstudios Ltd | Arts & recreation | 2018 |
| CND Windows Limited | Construction | 2019 |
| Coach House Property Management Limited | Real estate | 1984 |
| Coaching (SE) Limited | Arts & recreation | 2017 |
| Coast Holiday Lettings Limited | Real estate | 2019 |
| Coastal Property Company Limited | Construction | 2016 |
| Cobalt Labs UK, Ltd | Information & communication | 2022 |
| Cobden Place (Hailsham) Management Company Limited | Households | 2023 |
| Cochrane & Wilson Ltd | Real estate | 2007 |
| Cochrane Design 9 Limited | Real estate | 2018 |
| Codefaber Limited | Information & communication | 2012 |
| Codrin Ltd | Transport & logistics | 2016 |
| Coffee ORE Tea Ltd | Hospitality | 2020 |
| Coffee Trade Ltd | Wholesale & retail | 2025 |
| Coffey Investments Ltd | Financial services | 2021 |
| Colben Properties Limited | Real estate | 2002 |
| Colin Fitzgerald Consultancy Limited | Education | 2023 |
| Collington Hastings Limited | Hospitality | 2012 |
| Collins Computers Limited | Information & communication | 1982 |
| Colombo 16 Ltd | Hospitality | 2022 |
| Colours Electrical Wholesale Limited | Wholesale & retail | 2017 |
| Colours Tiles Limited | Wholesale & retail | 2019 |
| Colours Timber Ltd | Wholesale & retail | 2012 |
| Common Clay CIC | Arts & recreation | 2023 |
| Common Treasury CIC | Hospitality | 2025 |
| Communications & Sound Systems Limited | Wholesale & retail | 1996 |
| Compass Productions Limited | Information & communication | 2013 |
| Conant Engineering Limited | Construction | 2003 |
| Concept Vacuum Limited | Professional & scientific | 2023 |
| Confidential Consulting Services Limited | Extraterritorial | 2000 |
| Conqueror Refuse and Waste Ltd | Water & waste | 2021 |
| Conquest Cleaning Services Limited | Administrative & support | 2000 |
| Consent Through Sport Ltd | Education | 2024 |
| Conservation & Leisure Services Limited | Other services | 1997 |
| Constant Creative Limited | Professional & scientific | 2021 |
| Construction Evolution Limited | Construction | 2022 |
| Consulting 77 Ltd | Real estate | 2019 |
| Contour Contracts Limited | Construction | 2006 |