| C King Holdings Ltd | Extraterritorial | 2013 |
| C M Building Renovations Ltd | Construction | 2021 |
| C P Blasting Ltd | Manufacturing | 2003 |
| C P G Building Solutions Limited | Construction | 2023 |
| C Projekt 2 Limited | Financial services | 2025 |
| C Ramsdale & SON Ltd | Water & waste | 2022 |
| C&C Mechanical Solutions Limited | Construction | 2023 |
| C&S Ball Limited | Construction | 2013 |
| C&S Building & Flooring Ltd | Construction | 2025 |
| C&S Invest Ltd | Real estate | 2022 |
| C&S Security Services Ltd | Administrative & support | 2023 |
| C&T Hygienic Interiors Ltd | Administrative & support | 2022 |
| C.C. Motors (South Yorkshire) Limited | Wholesale & retail | 2024 |
| C.C.T. Limited | Manufacturing | 1989 |
| C.D.Glossop Ltd | Manufacturing | 2019 |
| C.E.S Contracting Ltd | Manufacturing | 2020 |
| C.K Home Improvements Ltd | Construction | 2024 |
| C.K. Associates Limited | Administrative & support | 1991 |
| C.L. Brookes Limited | Manufacturing | 1962 |
| C.L.A.S. Services (UK) Ltd | Information & communication | 2010 |
| C21 Group Limited | Information & communication | 2016 |
| C21 IOT Limited | Professional & scientific | 2015 |
| CAB Fabrication Solutions Ltd | Manufacturing | 2026 |
| Cabo Verde Property Limited | Real estate | 2023 |
| Cacb Consultancy Ltd | Administrative & support | 2025 |
| Caffrey Approved Design Limited | Professional & scientific | 2024 |
| CAI & Co Chauffeurs Limited | Transport & logistics | 2025 |
| Caisteal Residential Ltd | Real estate | 2023 |
| Cake Face Beauty Ltd | Other services | 2022 |
| Caldic (UK) Ltd | Wholesale & retail | 1986 |
| Caldic Ingredients UK Ltd. | Manufacturing | 2014 |
| Call PRU Limited | Hospitality | 2023 |
| Call YTS Limited | Hospitality | 2023 |
| Calow Chippy Ltd | Hospitality | 2026 |
| Calow Gala Association CIC | Administrative & support | 2023 |
| Calow Lane M.O.T. Centre Ltd | Wholesale & retail | 2009 |
| Calverts Butchers(Midlands) Limited | Hospitality | 2023 |
| Calverts Mobile Butchers (Yorkshire) Limited | Hospitality | 2015 |
| CAM Property & Developments Ltd | Real estate | 2025 |
| Cambridge Square Ltd | Health & social care | 2019 |
| Cambrix Ltd | Construction | 2018 |
| Camerauk Ltd | Wholesale & retail | 2021 |
| Cameron Craig Wood Limited | Professional & scientific | 2026 |
| Cameron Lunn Limited | Wholesale & retail | 2021 |
| Cameron Property Solutions Limited | Construction | 2017 |
| Camford Contractors Ltd | Construction | 2014 |
| Camio UK Limited | Wholesale & retail | 2021 |
| Campbell Harris Properties Limited | Real estate | 2015 |
| Campervan Accessories Limited | Wholesale & retail | 2016 |
| Camping On-Line Limited | Wholesale & retail | 2005 |
| Cancer Relief UK | Other services | 2008 |
| Candour Property Group Limited | Real estate | 2025 |
| Candycabs Limited | Information & communication | 2007 |
| Cani Holdings Limited | Financial services | 2021 |
| Cann Health Cultivation Limited | Health & social care | 2021 |
| Cann Health Limited | Health & social care | 2021 |
| Cann Solar Limited | Construction | 2026 |
| Cannon Capital Holdings Limited | Financial services | 2026 |
| Capelli Hairdressing Ltd | Other services | 2022 |
| Capital Competitions Ltd | Wholesale & retail | 2021 |
| Captain Vend Ltd | Extraterritorial | 2025 |
| Captured IT Ltd | Professional & scientific | 2026 |
| Car&Mar Ltd | Health & social care | 2019 |
| Card Grade Limited | Administrative & support | 2026 |
| Card Surplus Ltd | Wholesale & retail | 2024 |
| Cardonnel (Fieldbay) Limited | Health & social care | 2023 |
| Care Satellite Services Ltd | Professional & scientific | 2025 |
| Carenest Professionals Limited | Administrative & support | 2026 |
| Carers Sitting Service | Health & social care | 2007 |
| Caritas Innovation Ltd | Professional & scientific | 2022 |
| Carl Aaron Smithson GAS Services & Heating Supplies Ltd | Construction | 2015 |
| Carl Barratt Ltd. | Wholesale & retail | 2012 |
| Carl Bender Consulting Limited | Administrative & support | 2010 |
| Carl Dyke Auto Centre Ltd | Wholesale & retail | 2019 |
| Carlin Group Ltd | Financial services | 2017 |
| Carlin Property Ltd | Real estate | 2019 |
| Carlton Education and Training Ltd. | Extraterritorial | 1999 |
| Carlton Logistics Limited | Wholesale & retail | 2006 |
| Carlton Technologies Limited | Wholesale & retail | 1997 |
| Carly Smith PMU Artistry Ltd | Other services | 2022 |
| Carneil Precision Engineering Limited | Professional & scientific | 2004 |
| Carnell & Hedge Ltd | Other services | 2024 |
| Carnourish Ltd | Wholesale & retail | 2025 |
| Carolyn Mason Events Limited | Administrative & support | 2023 |
| Carpet Fresh Limited | Administrative & support | 2019 |
| Carr Vale Ventures Limited | Hospitality | 2014 |
| Carridice Limited | Professional & scientific | 1981 |
| Carrington Publishing House Limited | Information & communication | 2025 |
| Carrwood Holdings Limited | Real estate | 2021 |
| Carter Davenport Independent Design Limited | Professional & scientific | 2020 |
| Cartledge Farms Limited | Agriculture & fishing | 1985 |
| Cartledge Properties Limited | Real estate | 2012 |
| Cary UK Holding Ltd | Financial services | 2018 |
| Cary UK Ltd | Wholesale & retail | 1987 |
| Casa Hotel Holdings Limited | Hospitality | 2009 |
| Casa Hotel Limited | Hospitality | 2009 |
| Casa Property Holdings Limited | Real estate | 2021 |
| Casa Property Limited | Construction | 2009 |
| Casa Real Estates Limited | Real estate | 2016 |
| Cascade Highways Consultancy Services Ltd | Information & communication | 2021 |