| Castleside Electrical Ltd | Construction | 2015 |
| Catalogue Ltd | Extraterritorial | 1993 |
| Cater Clean 24SEVEN Ltd | Extraterritorial | 2011 |
| Caterpillar Captions Ltd | Information & communication | 2022 |
| Catfish Property Limited | Real estate | 2022 |
| Catmere Asset Management Limited | Real estate | 2012 |
| CB Resourcing Ltd | Administrative & support | 2014 |
| Cbea Limited | Wholesale & retail | 2022 |
| CBN Plant Hire Limited | Professional & scientific | 2001 |
| Cbpg Innovations Limited | Financial services | 2007 |
| CC Accountancy Limited | Professional & scientific | 2016 |
| CC Arch Developments Limited | Construction | 2023 |
| CC Arch Housing Limited | Households | 2023 |
| CC Arch Scaffolding Ltd | Construction | 2026 |
| CCM Consult Limited | Professional & scientific | 2013 |
| CE Limited | Extraterritorial | 2008 |
| Cedar Close Management Limited | Real estate | 2006 |
| Cel-Soft Ltd | Information & communication | 2000 |
| Centag Properties Ltd | Real estate | 2024 |
| Centaureans Ltd. | Information & communication | 2017 |
| Ceres Group Consultancy Limited Liability Partnership | | 2023 |
| Ceres Research Ltd | Professional & scientific | 2024 |
| Ceres Rural LLP | | 2020 |
| Certa 1492 Limited | Professional & scientific | 2016 |
| Cetmet Ltd | Real estate | 2025 |
| Chainlink Construction Ltd | Construction | 2023 |
| Chaise Management Ltd | Extraterritorial | 2013 |
| Chalk Place Management Company Limited | Households | 2018 |
| Champion RV Hire Ltd | Wholesale & retail | 2024 |
| Champion RV Sales Limited | Wholesale & retail | 2021 |
| Channel Electric Equipment Limited | Wholesale & retail | 1967 |
| Chaplin Business Consulting Ltd | Professional & scientific | 2014 |
| Chaptersix Limited | Professional & scientific | 2024 |
| Character Inns Limited | Arts & recreation | 1992 |
| Charflow Services Ltd | Professional & scientific | 2020 |
| Charge to Phone Limited | Information & communication | 2013 |
| Charles Britton Limited | Extraterritorial | 2008 |
| Chartlands Farm Limited | Real estate | 1964 |
| Chartwell Accountants LLP | | 2010 |
| Chaterco Ltd | Hospitality | 2022 |
| Chauvel London Ltd | Wholesale & retail | 2022 |
| Chelor Ltd | Construction | 2017 |
| Cherry Garden Projects Limited | Professional & scientific | 2013 |
| Cheshire Coppice PV Ltd | Energy | 2014 |
| Chesterford Engineering Limited | Wholesale & retail | 2004 |
| Chesterford Limited | Wholesale & retail | 2007 |
| Chips Cottage Apiaries Ltd | Wholesale & retail | 2008 |
| Chloes Designs Limited | Wholesale & retail | 2021 |
| Chloes Jewellers Holdings Limited | Financial services | 2024 |
| Chloes Jewellery Limited | Wholesale & retail | 2021 |
| Chloes Jewellery Wages Limited | Wholesale & retail | 2022 |
| Chloes Rentals Limited | Wholesale & retail | 2022 |
| Choicepledge Limited | Households | 1988 |
| Chris Barker Surveyor Ltd | Professional & scientific | 2022 |
| Chris Eastwood Automotive Limited | Administrative & support | 1995 |
| Chrysalis Building & Project Consultancy Ltd | Administrative & support | 2020 |
| Church Edale Limited | Construction | 2014 |
| Church Street Dental Surgery Ltd | Health & social care | 2013 |
| Churchgate Consulting Ltd | Other services | 2024 |
| Cialice Consulting Ltd | Health & social care | 2026 |
| Cinnamon Letters Ltd | Professional & scientific | 2008 |
| City Riverside Properties Limited | Real estate | 2016 |
| Citycourt Developments Limited | Administrative & support | 2002 |
| Cityshape Investments Limited | Financial services | 2012 |
| CJB Property & Estates Ltd | Real estate | 2025 |
| CJK Homes Ltd | Real estate | 2024 |
| Cladpro Limited | Construction | 1999 |
| Claire Parke Hair Ltd | Other services | 2025 |
| Claire Richards Limited | Arts & recreation | 2008 |
| Clare Mulley Limited | Information & communication | 2012 |
| Clare Reid Marketing Limited | Professional & scientific | 2023 |
| Clarendon (Putney) LLP | | 2023 |
| Clarity UK Ltd | Construction | 1998 |
| Classic Car Valuations Ltd | Professional & scientific | 2014 |
| Clatterbury Homes Limited | Construction | 2024 |
| Clavering & Arkesden Preschool | Education | 2009 |
| Clavering Electrical Services Limited | Energy | 2013 |
| Clean Air 24SEVEN Ltd | Extraterritorial | 2011 |
| Clean Slate Clinic Ltd | Health & social care | 2023 |
| Clear Champion Limited | Information & communication | 2009 |
| Clear Solutions TPI Ltd | Construction | 2022 |
| Cleared for Takeoff Limited | Professional & scientific | 2022 |
| Cleerun Services Ltd | Agriculture & fishing | 2020 |
| Cleftbridge Limited | Manufacturing | 1984 |
| Clement Close Clavering Management Company Limited | Households | 2022 |
| Cleomanagement Limited | Professional & scientific | 2025 |
| Clikfix Ltd | Other services | 2010 |
| Climate Autogates Limited | Manufacturing | 2002 |
| Clinpro Ltd | Extraterritorial | 2020 |
| Clip & Clean Grooming Ltd | Other services | 2026 |
| Clive Flood Advisory Services Ltd | Professional & scientific | 2024 |
| Club Nexus (2729) Ltd | Hospitality | 2026 |
| Club Nexus Limited | Hospitality | 2026 |
| CM Tenger (NW) Limited | Real estate | 2020 |
| CMZ (Machinery) Limited | Wholesale & retail | 1993 |
| CN Wealth Limited | Financial services | 2013 |
| Cnzw Developments Ltd | Construction | 2021 |
| Coak Construction Ltd | Construction | 2012 |
| Coegi Consulting Ltd. | Professional & scientific | 2022 |
| Coghlan Care Ltd | Administrative & support | 2022 |