| Costin CR Ltd | Construction | 2026 |
| Cosurgical Ltd | Health & social care | 2020 |
| Cosytotschildcare Limited | Health & social care | 2021 |
| Cotswold Creative Living Limited | Construction | 2014 |
| Coulton's Bread Limited | Wholesale & retail | 1993 |
| Countrywide Building Solutions Ltd | Construction | 2025 |
| Countrywide Contractors Limited | Construction | 1998 |
| Countrywide Plant Solutions Limited | Construction | 2015 |
| County (Oundle) Limited | Real estate | 2012 |
| Countyland Ltd | Real estate | 2010 |
| Court Dental Limited | Health & social care | 2023 |
| Courtland Avenue SPV Limited | Real estate | 2025 |
| Cover Sports Publishing Ltd | Manufacturing | 2013 |
| Covercy Europe Ltd | Administrative & support | 2015 |
| Covue IT Ltd | Information & communication | 2013 |
| Cowes Limited | Wholesale & retail | 2000 |
| Cowley Hill Stables Limited | Households | 2022 |
| CP Design and Project Ltd | Professional & scientific | 2018 |
| CP Homes and Projects Ltd | Construction | 2019 |
| CP Property & Capital Ltd | Real estate | 2015 |
| CP Props Ltd | Arts & recreation | 2021 |
| CP Sets & Scenery Limited | Information & communication | 2018 |
| CPX Group Ltd | Administrative & support | 2013 |
| Crabtree Productions Ltd | Administrative & support | 2015 |
| Crad Glazing Ltd | Construction | 2026 |
| Craft Experts Ltd | Construction | 2019 |
| Craftroots London Group Ltd | Professional & scientific | 2026 |
| Craftroots London Ltd | Professional & scientific | 2026 |
| Craig Comp Limited | Administrative & support | 2019 |
| Craig Energy Supply Limited | Energy | 2025 |
| Craig's Music Ltd | Wholesale & retail | 2004 |
| Craigmount (Freehold) Ltd | Real estate | 2025 |
| Craigmount Management Company Limited | Households | 1985 |
| Crawford & John Limited | Information & communication | 2013 |
| Crbir Construction Limited | Construction | 2025 |
| Crbs Ventures Limited | Financial services | 2020 |
| Creation Media Limited | Professional & scientific | 2006 |
| Creation Musical Services Limited | Arts & recreation | 2009 |
| Creative Clothing 2 Ltd. | Wholesale & retail | 2015 |
| Creative Joaillerie Ltd | Wholesale & retail | 2019 |
| Creative Piece Limited | Professional & scientific | 2009 |
| Creative Stages Ltd | Information & communication | 2022 |
| Crestshaw Limited | Professional & scientific | 2024 |
| Creswell Holdings Limited | Professional & scientific | 2024 |
| Criminal Creaturae Ltd | Arts & recreation | 2021 |
| Crimson Jewels Ltd | Wholesale & retail | 2011 |
| Crisp Holdings Limited | Information & communication | 2010 |
| Crisp Ibiza Ltd | Hospitality | 2017 |
| Crispin Mallard Ltd | Real estate | 2018 |
| Cristi's Food Ltd | Hospitality | 2019 |
| CRM Projects UK Limited | Professional & scientific | 2023 |
| Croke Stewart Finance Ltd | Financial services | 2018 |
| Croquet Facilities LLP | | 2015 |
| Cross Harbour Consultancy Limited | Construction | 2016 |
| Cross Harbour Investment Limited | Construction | 2016 |
| Cross Harbour Property Limited | Construction | 2016 |
| Cross Keys Molinaro Ltd | Hospitality | 2022 |
| Cross-Events Ltd. | Arts & recreation | 2016 |
| Crossfield Properties Ltd | Hospitality | 2018 |
| Crosshall Limited | Wholesale & retail | 2000 |
| Crossways Recruitment Limited | Administrative & support | 2005 |
| Crouching Tiger Limited | Manufacturing | 2018 |
| Crown and Compass Tours Ltd | Administrative & support | 2025 |
| Crown Buildings Management Limited | Households | 2024 |
| Crown Recruitment Ltd | Construction | 2022 |
| Crown ROW Ltd | Real estate | 2025 |
| Crownedway Corporations Ltd | Administrative & support | 2024 |
| Crugiau Properties Limited | Construction | 2005 |
| Crystal Salt Cave Ltd | Health & social care | 2024 |
| CS Property Portfolio Ltd | Real estate | 2025 |
| CS Software Consultancy Ltd | Information & communication | 2015 |
| CS Travel Solutions Ltd | Administrative & support | 2022 |
| CSE Building Ltd | Construction | 2018 |
| CSL Analytics Ltd | Information & communication | 2024 |
| CTA & Macro Strategies for Corporations Only Ltd | Financial services | 2000 |
| CTA Topco Limited | Professional & scientific | 2017 |
| CTC+ Ltd | Real estate | 2015 |
| CTL Harford Ltd | Construction | 2017 |
| CTU Maintenance Services Ltd | Construction | 2021 |
| Cubixel Ltd | Information & communication | 2022 |
| Cubster | Other services | 2016 |
| Culland Limited | Wholesale & retail | 2000 |
| Culley Lifford Hall Ltd | Professional & scientific | 2002 |
| Culley Limited | Wholesale & retail | 2000 |
| Curate Health Ltd | Health & social care | 2020 |
| Curds and Whey Ltd | Hospitality | 2014 |
| Currency Square London Limited | Professional & scientific | 2022 |
| Curry Garden Limited | Hospitality | 2017 |
| Curved Edge Ltd | Manufacturing | 2023 |
| CUZ & Co Construction Ltd | Construction | 2026 |
| CV Installations Ltd | Construction | 2024 |
| Cvepulse Limited | Information & communication | 2021 |
| CVR Recycling Ltd | Manufacturing | 2025 |
| CVS (Watford) Limited | Wholesale & retail | 2023 |
| CW Group Holdings Limited | Financial services | 2023 |
| CW Hembry Property Management Ltd | Real estate | 2021 |
| CW Property Holdings Limited | Real estate | 2017 |
| CWM Estate Ltd | Real estate | 2022 |
| CWM Renovations Ltd | Construction | 2023 |
| CWP Resources Limited | Education | 2013 |