| Climateshield Solar Limited | Construction | 2020 |
| Climbing Services Ltd | Arts & recreation | 2018 |
| Clinical Anaesthesia Services Limited | Health & social care | 2014 |
| Clinical Wholesalers Ltd | Health & social care | 2022 |
| Clinicial Management Limited | Professional & scientific | 2026 |
| Cliniclo Aesthetics Limited | Other services | 2019 |
| Clinyx Care Ltd | Health & social care | 2023 |
| Clipeum IT (Alpha) Ltd | Financial services | 2020 |
| Clipeum IT (Beta) Ltd | Financial services | 2022 |
| Clipeum IT Ltd | Information & communication | 2019 |
| Clippety Clop Ltd | Agriculture & fishing | 2018 |
| Clique Energy Ltd | Energy | 2014 |
| Clitheroe Aerospace Engineering Ltd | Manufacturing | 2025 |
| Clitheroe Engineering Ltd | Manufacturing | 2025 |
| Clitheroe Heavy Engineering Ltd | Manufacturing | 2025 |
| Clitheroe Light Engineering Ltd | Manufacturing | 2024 |
| Clitheroe Precision Engineering Ltd | Manufacturing | 2025 |
| Clix Media Ltd | Extraterritorial | 2011 |
| CLM Finance Limited | Professional & scientific | 2007 |
| CLN Grounds Maintenance Limited | Administrative & support | 2017 |
| Clock Face Properties Limited | Real estate | 2017 |
| Clocktower Properties Northwest Limited | Real estate | 2017 |
| Clockwise Ventures Ltd | Professional & scientific | 2019 |
| Clockwork 24 Ltd. | Transport & logistics | 2004 |
| Clok Associates Limited | Wholesale & retail | 2016 |
| Close Welding Services Ltd | Manufacturing | 2025 |
| Closed Circuit Systems Limited | Administrative & support | 1998 |
| Closedby.Ai Ltd | Information & communication | 2024 |
| Closetrade Limited | Wholesale & retail | 1994 |
| Cloth Store Ltd | Hospitality | 2019 |
| Clothes Point | Other services | 2023 |
| Clothes Point a | Other services | 2023 |
| Clothes Point B | Other services | 2023 |
| Clothes Point C | Other services | 2023 |
| Clothes Point D | Other services | 2023 |
| Clothes Point E | Other services | 2023 |
| Clothes Point F | Other services | 2023 |
| Clothes Point G | Other services | 2023 |
| Clothes Point H | Other services | 2023 |
| Clothes Point North | Other services | 2024 |
| Clothing Wholesalers Limited | Wholesale & retail | 2018 |
| Cloud Adept Limited | Information & communication | 2014 |
| Cloud Clever Limited | Information & communication | 2011 |
| Cloud Equestrian Ltd | Other services | 2022 |
| Cloud Gowns Ltd | Wholesale & retail | 2024 |
| Cloud Occupational Therapy Ltd | Health & social care | 2023 |
| Cloud Plastics Ltd | Manufacturing | 2025 |
| Cloud Search Ltd | Administrative & support | 2014 |
| Cloud Skills Guild Limited | Information & communication | 2024 |
| Cloud Traffic Management Ltd | Construction | 2019 |
| Cloud Trumph UK Ltd | Information & communication | 2023 |
| Cloudaz Limited | Information & communication | 2017 |
| Cloudedge IT Limited | Information & communication | 2025 |
| Cloudkicker Consulting Limited | Professional & scientific | 2025 |
| Cloudrig Limited | Information & communication | 2021 |
| Cloudtunes Digital Services Limited | Information & communication | 2021 |
| Cloudvanta Solutions Ltd | Information & communication | 2026 |
| Clover Cars (Plumley) Limited | Wholesale & retail | 2023 |
| Clover Homes for Children Ltd | Health & social care | 2023 |
| Clover Leaf Childcare Limited | Education | 2015 |
| Cloverleaf Trading Limited | Wholesale & retail | 2018 |
| CLP Consulting Limited | Professional & scientific | 2023 |
| CLS Joinery & Building Limited | Construction | 2007 |
| Clsoccer Ltd | Education | 2026 |
| Club Acai Limited | Hospitality | 2026 |
| Club Boys Barber Ltd | Other services | 2025 |
| Club Creative Ltd | Professional & scientific | 2022 |
| Clubex Limited | Arts & recreation | 2025 |
| Clubhouse-Assets Ltd | Financial services | 2025 |
| Clubhouse-Gyms (Blackburn) Ltd | Arts & recreation | 2025 |
| Clubhouse-Uk Ltd | Arts & recreation | 2025 |
| Clucky Rice Limited | Hospitality | 2024 |
| Clusera Ltd | Information & communication | 2026 |
| Clutter Cutters Ltd | Construction | 2025 |
| Clyde Maley & Sons Limited | Construction | 2021 |
| CM Crypto Mining Ltd | Financial services | 2021 |
| CM Everywhere Limited | Professional & scientific | 2026 |
| CM Properties Limited | Real estate | 2023 |
| CM Royle Properties Ltd | Real estate | 2019 |
| Cmack Limited | Wholesale & retail | 2020 |
| CMC Autos Enterprise Ltd | Wholesale & retail | 2024 |
| CMC Quality Inspection Ltd | Administrative & support | 2024 |
| CME Grimshaw Investment Limited | Real estate | 2024 |
| CME Grimshaw Properties Limited | Real estate | 2024 |
| CMF Consulting Ltd | Professional & scientific | 2025 |
| Cmfoptics Ltd | Wholesale & retail | 2025 |
| CMG Coaching Limited | Health & social care | 2023 |
| CMH Energy & Property Services Ltd | Real estate | 2025 |
| Cmmar Property Ltd | Real estate | 2025 |
| CMP Batteries Pensions Limited | Financial services | 1989 |
| CMP Online Ltd | Wholesale & retail | 2022 |
| CMP Software Limited | Information & communication | 2011 |
| CMR Auto Limited | Wholesale & retail | 2022 |
| CMS Doors in Bolton Limited | Wholesale & retail | 2025 |
| CMT Direct Properties Ltd | Real estate | 2022 |
| CNA Media Limited | Professional & scientific | 2023 |
| CNA Northwest Ltd | Hospitality | 2026 |
| Cndy International Limited | Information & communication | 2024 |
| CNI Solutions Ltd | Information & communication | 2013 |
| Cnica Ltd | Administrative & support | 2019 |