| Clique AV Ltd | Construction | 2016 |
| Clive Bass Enterprises Ltd | Construction | 2010 |
| CLM Builder Ltd | Administrative & support | 2012 |
| CLS 2025 Investments | Real estate | 2015 |
| CLS Prop Ltd | Real estate | 2020 |
| Clwfm Ltd | Households | 2019 |
| CM Quality Ltd | Professional & scientific | 2016 |
| CMC Plant and Construction Ltd | Construction | 2022 |
| CN Seeds Holdings Limited | Financial services | 2015 |
| Coachsafe Ltd | Public administration | 2015 |
| Coad Property Limited | Real estate | 2019 |
| Coast Living Ltd | Real estate | 2019 |
| Cocoon Architects Limited | Professional & scientific | 2022 |
| Cocreate+ Ltd | Education | 2025 |
| Coding After 9 Ltd | Information & communication | 2016 |
| Coebros Limited | Professional & scientific | 2013 |
| Cole Ambrose Limited | Agriculture & fishing | 1943 |
| Collaborit Consulting Ltd | Information & communication | 2024 |
| Commercial & Quantum Limited | Professional & scientific | 2016 |
| Commercial Floor Sanding Ltd | Construction | 2010 |
| Common Farm,Limited | Agriculture & fishing | 1945 |
| Commutrol (UK) Limited | Information & communication | 2001 |
| Compass Construction & Design Limited | Construction | 2009 |
| Compass Philanthropy Collective Limited | Professional & scientific | 2025 |
| Compassion Care Crew Ltd | Administrative & support | 2026 |
| Complete Service Company (UK) Limited | Manufacturing | 2013 |
| Completo Limited | Wholesale & retail | 2025 |
| Compton Advisory Ltd | Professional & scientific | 2025 |
| Computer Displays UK Ltd | Administrative & support | 2005 |
| Concept Bloom Limited | Wholesale & retail | 2016 |
| Concordia Homes Limited | Construction | 2012 |
| Concordia UK Investments Limited | Real estate | 2001 |
| Conflair Elite Property Sourcing Ltd | Real estate | 2024 |
| Conflair Limited | Real estate | 2024 |
| Conflair Properties Ltd | Hospitality | 2024 |
| Connect Executive Resourcing Limited | Administrative & support | 1999 |
| Connexbox Holdings Ltd | Construction | 2022 |
| Connexbox Ltd | Administrative & support | 2009 |
| Construction Gateway Limited | Education | 2007 |
| Contentious Trusts and Probate Services Limited | Other services | 2025 |
| Cook Carpentry & Interiors Limited | Construction | 2014 |
| Cook to Order Limited | Hospitality | 2026 |
| Cooldog Studios Limited | Arts & recreation | 2022 |
| Cooper 4 Limited | Real estate | 2024 |
| Coopers Court (Linton) Management Company Limited | Households | 2021 |
| Core Commercial Resolutions Limited | Professional & scientific | 2026 |
| Corion Forge Ltd | Information & communication | 2024 |
| Corkers Crisps Ltd | Manufacturing | 2007 |
| Corkhouse Limited | Administrative & support | 2013 |
| Cornwell Contracting Limited | Agriculture & fishing | 2015 |
| Corporate Accountability Network Limited | Professional & scientific | 2019 |
| Corrboard Bioenergy Limited | Manufacturing | 2016 |
| Cosy Nook Properties Ltd | Real estate | 2025 |
| Country Club Pet Hotel Limited | Other services | 2006 |
| Country Oaks Ltd | Health & social care | 2020 |
| Covelstone Holdings Ltd | Financial services | 2020 |
| Covelstone Investments Limited | Financial services | 1992 |
| Covelstone Limited | Financial services | 1988 |
| Covelstone Property Limited | Real estate | 2007 |
| Coverjig Ltd | Information & communication | 2019 |
| Cowell CNC Ltd | Manufacturing | 2015 |
| COX and Kirby Entertainment Ltd | Arts & recreation | 2024 |
| Cozynest Services Limited | Administrative & support | 2025 |
| CR Concrete Ltd | Construction | 2022 |
| Craft & Artisan Group Limited | Financial services | 2009 |
| Craftforge Limited | Manufacturing | 2026 |
| Craggyskitchen Ltd | Hospitality | 2025 |
| Craig Hobbs Commercial Ltd | Wholesale & retail | 2022 |
| Crescent Stairs Limited | Professional & scientific | 1978 |
| Crest Communication Limited | Information & communication | 2010 |
| Crest Roofing & General Builders Ltd | Construction | 2007 |
| CRF Consulting Limited | Professional & scientific | 2012 |
| CRG Consultancy Limited | Professional & scientific | 2025 |
| Criftins Associates Limited | Professional & scientific | 2008 |
| Crimson Herd Limited | Wholesale & retail | 2026 |
| Cristal Investments Group Limited | Administrative & support | 2016 |
| Croft Bank Developments Limited | Construction | 2009 |
| Croftgate Residents Company Limited | Real estate | 1970 |
| Croslaw Direct Ltd | Wholesale & retail | 2003 |
| Cross Keys Consultancy Ltd | Professional & scientific | 2025 |
| Crown Garage Limited | Wholesale & retail | 1996 |
| Crown Yard Developments Limited | Real estate | 2016 |
| Cryptoclaims.Pro Limited | Financial services | 2023 |
| Crystal Skull Trading Ltd | Administrative & support | 2025 |
| CSC Global Management Ltd | Wholesale & retail | 2026 |
| Cultural Capital Consultancy Limited | Other services | 2014 |
| Cumbric Care Limited | Health & social care | 2016 |
| Cvlqa Ltd | Professional & scientific | 2011 |
| CW Visuals Ltd | Information & communication | 2026 |
| CWM Building Projects Ltd | Construction | 2023 |
| Cyberfrosc Consulting Limited | Professional & scientific | 2025 |
| Cybershark Recruitment Limited | Administrative & support | 2021 |
| Cygnus Park Management Company Limited | Real estate | 2008 |
| Cytek Biosciences Ltd | Professional & scientific | 2023 |
| Czech Holdings Ltd | Financial services | 2022 |
| D C Produce Limited | Agriculture & fishing | 1997 |
| D J Francis Limited | Construction | 2005 |
| D J Houghton Construction Ltd | Construction | 2024 |
| D R V Sales Limited | Wholesale & retail | 2026 |
| D S Electrical ELY Ltd | Construction | 2018 |