| Cloudformix Consulting Ltd | Information & communication | 2025 |
| Cloudpine Software Solutions Ltd | Information & communication | 2019 |
| Cloverfield Holdings Limited | Financial services | 2019 |
| CLS Accounting Solutions Limited | Professional & scientific | 2025 |
| Clutch Motors Limited | Wholesale & retail | 2025 |
| Clyde Dent Company Limited | Wholesale & retail | 2014 |
| Clyde Global Health Care Ltd | Health & social care | 2021 |
| Cmcc Electrical Services Limited | Construction | 2026 |
| CMR Group Limited | Administrative & support | 1996 |
| Cmrworldwide Ltd | Administrative & support | 2006 |
| CMS (Cable Management Supplies) PLC | Extraterritorial | 1996 |
| CMS Carpets (Newbury) Limited | Wholesale & retail | 2019 |
| CMS Carpets (Newbury) MBO Limited | Financial services | 2022 |
| CMS Carpets (Winchester) Limited | Wholesale & retail | 2019 |
| Co Create Media Ltd | Professional & scientific | 2024 |
| Coach & Courses Ltd | Hospitality | 2023 |
| COACH1 Limited | Transport & logistics | 2011 |
| Coachnudge Limited | Administrative & support | 2013 |
| Coatham Tyre Centre Limited | Transport & logistics | 1982 |
| Cobal Sign Systems Limited | Manufacturing | 1981 |
| Cobbetts View Management Company Limited | Other services | 2010 |
| Cochrane Strategic Development Limited | Construction | 2023 |
| Codexx Associates Limited | Professional & scientific | 2002 |
| Codilink UK Ltd | Information & communication | 2007 |
| Codrington Associates Ltd | Financial services | 2002 |
| Cogency Labs Ltd | Professional & scientific | 2019 |
| Cogent CRE Recruitment Ltd | Administrative & support | 2023 |
| Cogent Distribution Limited | Information & communication | 2015 |
| Cognito Limited | Information & communication | 1992 |
| Cold Rolled Solutions Group Limited | Construction | 2019 |
| Cold Turkey Entertainment Ltd | Information & communication | 2019 |
| Cole Communications Limited | Information & communication | 1998 |
| Colilot Ventures Limited | Professional & scientific | 2021 |
| Colin Donald Fuels Ltd | Wholesale & retail | 2022 |
| Colin Farrant Machinery (2003) Limited | Administrative & support | 2003 |
| Collaton Mews Management Company Limited | Households | 2002 |
| Colley Associates Limited | Professional & scientific | 2013 |
| Collier & Robinson Limited | Manufacturing | 2019 |
| Collis Equine Ltd | Professional & scientific | 2020 |
| Collison Tools Ltd | Manufacturing | 2026 |
| Colon Limited | Information & communication | 2016 |
| Colour Properties Ltd | Real estate | 2018 |
| Colston Consultants Limited | Professional & scientific | 2014 |
| Colt Mackenzie Limited | Arts & recreation | 2003 |
| Colt Mackenzie Mcnair Limited | Arts & recreation | 2006 |
| Comfy Travelling Ltd | Administrative & support | 2020 |
| Commercial Security Consultancy Limited | Professional & scientific | 2026 |
| Commodore's ROW Management Limited | Hospitality | 2002 |
| Common Scents Fragrances Ltd | Manufacturing | 2026 |
| Community Tech Ltd | Information & communication | 2025 |
| Community United West Berkshire | Other services | 2020 |
| Compassion Restoration Limited | Health & social care | 2019 |
| Compleat Limited | Information & communication | 2020 |
| Compleat Software Limited | Information & communication | 1998 |
| Complete Knee Physiotherapy Ltd | Health & social care | 2026 |
| Complete PCB Services Limited | Administrative & support | 2006 |
| Compliance Consultancy Services (CCS) Ltd | Professional & scientific | 2020 |
| Component Coating and Repair Services Limited | Manufacturing | 1994 |
| Compose Sales Partners Ltd | Professional & scientific | 2026 |
| Compositus Ltd | Information & communication | 2013 |
| Compton Accounting Consultancy Ltd | Information & communication | 2025 |
| Compton Farm Barns Management Company Limited | Households | 2020 |
| Computer Medicine Limited | Information & communication | 2007 |
| Computer Salvage Specialists (Special Waste) Limited | Water & waste | 2001 |
| Computer Salvage Specialists Limited | Extraterritorial | 2009 |
| Conceptual Films Ltd | Information & communication | 2019 |
| Concrete Creations (UK) Limited | Manufacturing | 2014 |
| Conferan Limited | Information & communication | 2010 |
| Confluence Data Services Limited | Information & communication | 2024 |
| Connect ACR Supplies Ltd | Construction | 2020 |
| Connect Electrical Wholesale Limited | Wholesale & retail | 2010 |
| Connect Holdings Ltd | Financial services | 2020 |
| Connect Timber & Building Supplies Limited | Wholesale & retail | 2025 |
| Connecthow Limited | Other services | 2023 |
| Connections (AML) Limited | Extraterritorial | 1982 |
| Connexion Additive Technologies Limited | Financial services | 2018 |
| Connexion Limited | Information & communication | 1994 |
| Connexion Microwave Technologies Limited | Wholesale & retail | 2013 |
| Connexion PCB Solutions (Italy) Limited | Financial services | 2025 |
| Connexion PCB Solutions Limited | Financial services | 2025 |
| Connexion PCB Technologies Limited | Other services | 2017 |
| Connexion Precision Engineering Technologies Limited | Financial services | 2026 |
| Connexion Technologies Sales Limited | Professional & scientific | 2019 |
| Consolidated Fork Truck Services Limited | Transport & logistics | 2001 |
| Consolidated Resources Limited | Professional & scientific | 1989 |
| Construction Site Services Limited | Information & communication | 2002 |
| Consulega Limited | Professional & scientific | 2017 |
| Consulere Limited | Professional & scientific | 2022 |
| Consulting by James Ltd | Professional & scientific | 2024 |
| Continental Solutions Limited | Information & communication | 1994 |
| Continental Wine Bar Limited | Hospitality | 1994 |
| Contragent Limited | Information & communication | 2024 |
| Conxtd Technologies Limited | Administrative & support | 2018 |
| Conygray Limited | Professional & scientific | 2023 |
| Cookerburra Oven Cleaning Services (U.K.) Limited | Other services | 1994 |
| Coolpower Investments Limited | Real estate | 2025 |
| Coombesbury Farm Management Company Ltd | Households | 2020 |
| Copley Brickwork Limited | Construction | 1997 |
| Copse Dental Holdings Ltd | Financial services | 2018 |
| Coral Car Centre Ltd | Wholesale & retail | 2012 |