| Collinson Europe Limited | Professional & scientific | 2019 |
| Colshaw Hall Country Estate Limited | Hospitality | 2012 |
| Colshaw Hall Event Planning Ltd | Hospitality | 2015 |
| Colshaw Hall Holdings Limited | Hospitality | 2022 |
| Colshaw Hall Lodges Ltd | Hospitality | 2020 |
| Colshaw Hall Majorca Ltd | Financial services | 2016 |
| Colt Brands Limited | Wholesale & retail | 2015 |
| Command Line Solutions Ltd | Information & communication | 2017 |
| Commercial Caretakers Limited | Administrative & support | 1996 |
| Commodore B.V. | | 1996 |
| Compass Utilities Limited | Construction | 2017 |
| Compli With US Limited | Professional & scientific | 2011 |
| Conk & Squiggle Ltd | Wholesale & retail | 2020 |
| Conlon Properties Limited | Real estate | 2005 |
| Connect Seven International Limited | Real estate | 2019 |
| Connoisseurs Ltd | Real estate | 1989 |
| Conrad Associates LLP | | 2010 |
| Conran Estate Management Ltd | Administrative & support | 2015 |
| Consuelo Caravan Park Ltd | Hospitality | 2018 |
| Consuelo Services Ltd | Administrative & support | 2018 |
| Consumer Savings Network Limited | Financial services | 2014 |
| Contollo Group Limited | Financial services | 2023 |
| Contollo MEP Limited | Financial services | 2024 |
| COOK2ROAM Ltd | Hospitality | 2023 |
| Cookson Properties Trading Limited | Extraterritorial | 2011 |
| Coppervein Associates Limited | Real estate | 2015 |
| Coppock House Management Company Limited | Households | 2022 |
| Core Medica Limited | Professional & scientific | 2005 |
| Core Medical Ltd | Wholesale & retail | 2008 |
| Core Wellbeing Ltd | Real estate | 2025 |
| Corell Consultancy Ltd | Professional & scientific | 2021 |
| Cork and Cleaver Ltd | Hospitality | 2019 |
| Cornwall Electrical Wholesalers Limited | Extraterritorial | 1987 |
| Corporate 2 Commando Limited | Arts & recreation | 2024 |
| Corporate Culture Limited | Professional & scientific | 2024 |
| Corporate Wellbeing Group Limited | Professional & scientific | 2020 |
| Cortech Developments Limited | Information & communication | 1995 |
| COSMO8 UK Ltd | Wholesale & retail | 2024 |
| Cottage Staycations Ltd | Hospitality | 2022 |
| Cotton Hall Barns Management Company Limited | Extraterritorial | 2005 |
| Cotton Homes Limited | Extraterritorial | 2004 |
| Coughlan Media Solutions Limited | Professional & scientific | 2019 |
| Coul Construction Ltd | Construction | 2020 |
| Coul Interiors Ltd | Professional & scientific | 2020 |
| Country Estate Hospitality Limited | Hospitality | 2026 |
| Country Home Real Estate Limited | Real estate | 2026 |
| Countryfell Limited | Real estate | 1996 |
| Countryside and Garden Maintenance Ltd | Administrative & support | 2019 |
| Cover Leisure UK Ltd | Professional & scientific | 2018 |
| Covia Leisure Limited | Hospitality | 2019 |
| COX Development Limited | Real estate | 2018 |
| CPD Solutions (Holdings) Limited | Financial services | 2016 |
| CPD Solutions Limited | Education | 2000 |
| Cptco Limited | Financial services | 2015 |
| Crabber and Asker Limited | Extraterritorial | 2011 |
| Crabtreeai Ltd | Professional & scientific | 2025 |
| Craggy Island Investments Ltd | Real estate | 2021 |
| Crane Property & Development Company Limited(The) | Construction | 1961 |
| Cranford & Summer Ltd | Real estate | 2007 |
| Cranstone Estates Ltd | Construction | 2025 |
| CRE8IV Joinery Limited | Manufacturing | 2017 |
| Creaura Limited | Wholesale & retail | 2026 |
| Crest Commercial Property Ltd | Real estate | 2018 |
| CRL Business Consulting Ltd | Professional & scientific | 2020 |
| Croghan Consulting Limited | Professional & scientific | 2024 |
| Cross Keys Knutsford Limited | Hospitality | 2026 |
| Crosstown Solutions Limited | Professional & scientific | 2010 |
| CRU Investments Limited | Financial services | 2024 |
| Crucial Energy Limited | Professional & scientific | 2025 |
| Cryo Revive Limited | Health & social care | 2023 |
| Cryo Works Limited | Administrative & support | 2026 |
| CSH (Stoke) 24 Limited | Professional & scientific | 2006 |
| CTH Hair Ltd | Education | 2021 |
| CTM MCR Limited | Wholesale & retail | 2024 |
| CTP (UK) Holdings 1 Limited | Transport & logistics | 2024 |
| CTW IT Limited | Information & communication | 2018 |
| Cullen Millington Limited | Real estate | 2026 |
| Cultivate Customer Experience by Design Ltd | Professional & scientific | 2020 |
| Cummertreesannan Ltd | Real estate | 2024 |
| Cummins Utilities Limited | Construction | 2025 |
| Cupar Prop Limited | Real estate | 2024 |
| Cutting Room Capital Limited | Real estate | 2019 |
| CWB Design Ltd | Professional & scientific | 2008 |
| Cwfilm Limited | Information & communication | 2022 |
| Cygnus Chemical Consultancy Limited | Professional & scientific | 2025 |
| D & G Butterworth Properties Limited | Real estate | 2022 |
| D & J Irlam Holdings Limited | Financial services | 2020 |
| D & S Living UK Limited | Wholesale & retail | 2014 |
| D & V Catering Limited | Hospitality | 2019 |
| D Gaskell Consulting Limited | Information & communication | 2014 |
| D M Robins Limited | Information & communication | 2006 |
| DA Homes Ltd | Households | 2025 |
| Daadco Ltd | Construction | 2021 |
| Dafferns Knutsford LLP | | 2021 |
| Daisy Manor Events Limited | Hospitality | 2023 |
| Daleford Manor Limited | Hospitality | 2019 |
| Dales Agri Ltd | Agriculture & fishing | 2014 |
| Daley's Food Ltd | Hospitality | 2019 |
| Damsel in Design Ltd | Professional & scientific | 2023 |
| Daniel James Limited | Real estate | 2010 |