| Cleargen Environmental Services Ltd | Professional & scientific | 2022 |
| Cloudrythmics Limited | Information & communication | 2024 |
| CLR Ltd | Other services | 2019 |
| CLR Roofing Ltd | Construction | 2021 |
| CM Brick Ltd | Construction | 2024 |
| Cmbe Consult Ltd | Professional & scientific | 2017 |
| Cmbe Property Limited | Real estate | 2020 |
| Cmrs Management Ltd | Real estate | 2022 |
| Coach Travel Limited | Transport & logistics | 1990 |
| Coatit Plastering Ltd | Construction | 2025 |
| Coel Design Limited | Professional & scientific | 2014 |
| Coffey's Waste Management Ltd | Water & waste | 2021 |
| Coldicott Constructions Ltd | Construction | 2021 |
| Collina MEP Ltd | Professional & scientific | 2021 |
| Collins Carpets Limited | Wholesale & retail | 2025 |
| Colvin Signs Ltd | Administrative & support | 2025 |
| Combe Property Limited | Real estate | 2002 |
| Compass Inventories Limited | Administrative & support | 2009 |
| Complete Install Renewable Energies Limited | Construction | 2008 |
| Compton Statistical Consulting Limited | Information & communication | 2021 |
| Computer Soup Limited | Information & communication | 2006 |
| Comutel Telemarketing Services Limited | Professional & scientific | 2004 |
| Connolly Bros Ltd | Construction | 2019 |
| Consortium Studio Limited | Professional & scientific | 2022 |
| Construction Economist Group Limited | Professional & scientific | 2016 |
| Construction Industry Task Force Ltd | Hospitality | 2026 |
| Construction Marketing Associates Limited | Wholesale & retail | 1998 |
| Container Storage Units UK Limited | Administrative & support | 2018 |
| Content by Sinead Ltd | Information & communication | 2025 |
| Coolburn Air Conditioning Limited | Construction | 1986 |
| Cooling and Heating Technology Ltd | Construction | 2015 |
| Cooper + Cooper Interiors Ltd | Professional & scientific | 2018 |
| Copers Cope Management Company Limited | Real estate | 2018 |
| Corporate Passenger Logistics Ltd | Transport & logistics | 2025 |
| Cosar Holdings Ltd | Real estate | 2020 |
| Cotton and Cable Craft Liquid Limited | Administrative & support | 2017 |
| Count to SIX Productions Ltd | Information & communication | 2023 |
| County Carpentry and Building Ltd | Construction | 2017 |
| Court Investments Limited | Real estate | 1995 |
| Court Residential Property Limited | Financial services | 2013 |
| Coutts Electrical Contractors Ltd | Construction | 2020 |
| Covered Life Ltd | Financial services | 2021 |
| Covert Installations Limited | Administrative & support | 1999 |
| Cowden Residential Property Limited | Real estate | 1944 |
| Coxly Ltd | Real estate | 2022 |
| Crane Mdtl Limited | Financial services | 2020 |
| Creative Curry Girl Ltd. | Hospitality | 2020 |
| CRL Building & Property Maintanace Ltd | Construction | 2024 |
| Cronk Fitness Ltd | Arts & recreation | 2024 |
| Crosslight Ltd | Real estate | 2013 |
| Crowntree Limited | Extraterritorial | 2017 |
| Croydon Accident Repair Centre UK Limited | Wholesale & retail | 2007 |
| Crusade Legal Services Ltd | Professional & scientific | 2013 |
| Crystal Lease Lettings Ltd | Real estate | 2025 |
| Crystalline Care Solutions Ltd | Administrative & support | 2023 |
| CS Clarke Financial Services Limited | Financial services | 2016 |
| CTB Electrical Solutions Ltd | Construction | 2025 |
| Culver Build Ltd | Construction | 2025 |
| Cunningham Developments & Property Services Limited | Construction | 2012 |
| Cunningham Investment Group Ltd | Professional & scientific | 2024 |
| Currymania Limited | Hospitality | 2026 |
| Cyber Rescue Limited | Information & communication | 2014 |
| Cyril W. Bishop Engineering Services Limited | Professional & scientific | 2002 |
| Czar Management Ltd | Professional & scientific | 2018 |
| D & S Surfacing Limited | Construction | 2004 |
| D B Wilson Helicopters Limited | Manufacturing | 2014 |
| D Rees Roofing Limited | Construction | 2003 |
| D Scott Ltd | Real estate | 2021 |
| D.S.A.S. Limited | Wholesale & retail | 2001 |
| DA Farrell Services Limited | Construction | 2014 |
| DA UK Property Services Ltd | Real estate | 2021 |
| Dace Consultancy Services Ltd | Health & social care | 2025 |
| Dagon EN Ltd | Real estate | 2024 |
| Daiker Building Services Limited | Construction | 2002 |
| Dajz Solutions Ltd | Administrative & support | 2024 |
| DAN Pearce Art Ltd | Arts & recreation | 2013 |
| Dance-Worx's Limited | Arts & recreation | 2012 |
| Daniel 247 Limited | Construction | 2004 |
| Daniel Brem-Wilson Limited | Wholesale & retail | 2024 |
| Daniel COX Design Ltd | Professional & scientific | 2018 |
| Daniel Lucas Property Services Limited | Construction | 2011 |
| Daniels Consultancy Limited | Administrative & support | 2012 |
| Dannah Homes Ltd | Construction | 2018 |
| Dannys Bluelion Ltd | Transport & logistics | 2025 |
| Danvic Limited | Construction | 2009 |
| Daredevil Productions Limited | Information & communication | 2007 |
| Darren Shaw (Casting) Ltd | Manufacturing | 2007 |
| Dave Woodman Audio Limited | Professional & scientific | 2003 |
| David Garrick Stunts Limited | Arts & recreation | 2018 |
| David Haskoll Limited | Financial services | 2002 |
| Davies HR Consultants Ltd | Professional & scientific | 2018 |
| Day Building and Landscaping Ltd | Construction | 2026 |
| Dazzler Global Ltd | Professional & scientific | 2009 |
| DBI Projects Ltd | Construction | 2025 |
| DC Auto Services Ltd | Wholesale & retail | 2016 |
| DC Prime Exotics Ltd | Agriculture & fishing | 2026 |
| Debonneval Ltd | Hospitality | 2022 |
| Deborah Leighton Ltd | Professional & scientific | 2019 |
| Decantelo Ltd | Professional & scientific | 2016 |
| Delta T Commissioning Ltd | Construction | 2025 |