| Coriolis Energy Developments LLP | | 2019 |
| Coriolis Energy Limited | Professional & scientific | 2016 |
| Coriolis Energy Storage Limited | Energy | 2018 |
| Coriolis Property Partners Limited | Real estate | 2016 |
| Cornish Carpets Limited | Wholesale & retail | 1962 |
| Cornish Town Properties Limited | Administrative & support | 2016 |
| Cornwall Energy Recovery Holdings Ltd | Professional & scientific | 2006 |
| Cornwall Energy Recovery Ltd | Water & waste | 2006 |
| Coronel Private Care Ltd | Health & social care | 2026 |
| Corporate Express Chauffeurs Limited | Transport & logistics | 2001 |
| Corporate Gardener Ltd | Professional & scientific | 2020 |
| Corporate Translations Inc. (UK) Ltd | Professional & scientific | 2012 |
| Corpump (International) Limited | Professional & scientific | 2012 |
| Corpus Health Limited | Health & social care | 2024 |
| Cortado Ltd | Hospitality | 2024 |
| Cosmetic Beauty Limited | Health & social care | 2012 |
| Cosmonaut Leisure Ltd | Arts & recreation | 2020 |
| Cosmopolitan C&C Ltd | Hospitality | 2023 |
| Cosmopolitan Roses Netball Academy Ltd | Arts & recreation | 2023 |
| Cost Component Consulting Ltd | Construction | 2020 |
| Cosy Cleaners Ltd | Administrative & support | 2024 |
| Cosy Lets Ltd | Real estate | 2007 |
| Cotswold Flight Training Ltd | Education | 2024 |
| Coucha Limited | Hospitality | 2014 |
| Countdown Services Limited | Hospitality | 2025 |
| Countryside Heating & Plumbing Ltd | Construction | 2014 |
| Countrystore (Retail) Limited | Wholesale & retail | 1998 |
| County Construction Bucks Ltd | Construction | 2019 |
| County Golf Colleges Limited | Other services | 2020 |
| Courian Limited | Manufacturing | 2023 |
| Couser Accountants Limited | Professional & scientific | 2018 |
| Coventry Education Partnership Holdings Limited | Financial services | 2004 |
| Coventry Education Partnership Limited | Financial services | 2004 |
| Cover (France) Limited | Real estate | 1997 |
| Cover Commercial Limited | Real estate | 2004 |
| Cover Freeholds Limited | Real estate | 2008 |
| Cover Group Holdings Limited | Professional & scientific | 2002 |
| Cover Homes Limited | Construction | 1999 |
| Cover Rentals Limited | Real estate | 2002 |
| COX Green School | Education | 2011 |
| Coyle & Company Performance Consultants Ltd | Professional & scientific | 2015 |
| Cozzy Bedding Store Ltd | Wholesale & retail | 2025 |
| CP Construction Services Ltd | Construction | 2024 |
| Cpah Consultancy Limited | Other services | 2012 |
| Cpjlondon Ltd | Wholesale & retail | 2016 |
| CPQ Plus Limited | Information & communication | 2014 |
| CPS (International) Limited | Administrative & support | 2004 |
| Craftlast Limited | Construction | 2007 |
| Crafty TAP Room Limited | Hospitality | 2019 |
| Craufurd Hale Audit Services Limited | Professional & scientific | 2009 |
| Craufurd Hale LLP | | 2007 |
| Craufurd Hale US Tax Services Limited | Professional & scientific | 2019 |
| Craufurd Hale Wealth Management Limited | Financial services | 2018 |
| Cravers Limited | Extraterritorial | 2022 |
| Crawford CAB Rentals Ltd | Other services | 2011 |
| Crayon Dragons Ltd | Information & communication | 2023 |
| Crayon Limited | Information & communication | 2000 |
| Crayon Software Services Limited | Extraterritorial | 2000 |
| Craythorne Consulting Limited | Information & communication | 2018 |
| Crea Corporate Real Estate Advisors Ukeig | | 2016 |
| Creative Associates - Design & Comms Limited | Administrative & support | 2003 |
| Creative Capital Partners Ltd | Professional & scientific | 2023 |
| Creative Computing Solutions Limited | Information & communication | 1990 |
| Creative Contention Limited | Information & communication | 2012 |
| Creative Gold Limited | Manufacturing | 2015 |
| Creative Land Developers Limited | Professional & scientific | 1989 |
| Creative Rights Management Limited | Arts & recreation | 2020 |
| Creative Signs and Graphics Ltd | Professional & scientific | 2010 |
| Creatre Ltd | Information & communication | 2023 |
| Creffield Property Services Ltd | Other services | 2015 |
| Cremorne Communications Limited | Professional & scientific | 2015 |
| Crendon Properties Limited | Real estate | 1934 |
| Crescent Dale RTM Company Limited | Households | 2009 |
| Crest Cabling Solutions Ltd | Information & communication | 2024 |
| Crestmark Building Consultancy Ltd | Professional & scientific | 2026 |
| Crete Management Limited | Households | 1999 |
| Crime in Vision Limited | Information & communication | 2025 |
| Cristol Clear Living Ltd | Real estate | 2016 |
| Critical Services Specialist Limited | Administrative & support | 2026 |
| CRM Aviation Europe Limited | Transport & logistics | 2006 |
| Croasia Ltd | Manufacturing | 2026 |
| Croft Analytics Limited | Professional & scientific | 2020 |
| Cromhall Quarries, Limited | Professional & scientific | 1946 |
| Crowdens Limited | Wholesale & retail | 2009 |
| Crown Onlineuk Ltd | Wholesale & retail | 2025 |
| Crown Prestige Cars Ltd | Wholesale & retail | 2025 |
| Crownstone Projects Ltd | Professional & scientific | 2025 |
| CRS Finance Advisory Limited | Professional & scientific | 2025 |
| Crunchie Media Ltd | Administrative & support | 2015 |
| Crunchy Cakes Ltd | Information & communication | 2016 |
| Crux UK Ltd | Information & communication | 2007 |
| Crystal Fountain Sanctuary Limited | Professional & scientific | 2022 |
| CS Supplies and Services LLP | | 2013 |
| CSC Executives Limited | Other services | 2025 |
| Csha HR Consulting Ltd | Administrative & support | 2026 |
| CSK Technologies Limited | Administrative & support | 2025 |
| Csps Trustees Limited | Professional & scientific | 2017 |
| CT Innovate Limited | Professional & scientific | 2008 |
| CT Squirrel Group Ltd | Financial services | 2019 |
| CTC Recruitment Limited | Administrative & support | 2004 |