| Christian Cars Limited | Wholesale & retail | 1989 |
| Christian Couzens Limited | Administrative & support | 2007 |
| Christopher Holt Limited | Professional & scientific | 1999 |
| Christopher J. Atkinson Ltd | Real estate | 1998 |
| Christopher ST James Management Ltd | Real estate | 1989 |
| Chrome Dreams Media Ltd | Information & communication | 2001 |
| Chrysalis Chiropractic Ltd | Health & social care | 2022 |
| Cinquante Cinq Limited | Households | 2003 |
| Circle K | | 1992 |
| Circle K | | 1992 |
| Citizens Advice Merton and Lambeth Limited | Other services | 1994 |
| Citizens Advice Mole Valley | Health & social care | 2003 |
| City and European Asset Finance Limited | Financial services | 1997 |
| City Properties (NO 2) Limited | Professional & scientific | 1996 |
| City Rides Limited | Administrative & support | 2014 |
| Citygrove Investments Limited | Real estate | 2000 |
| Citysprint (UK) Bidco Limited | Financial services | 2016 |
| CJK Futures (UK) Ltd | Construction | 2009 |
| CJR Associates Ltd | Professional & scientific | 2006 |
| CJR Supplies Limited | Wholesale & retail | 2006 |
| Claims Services International Limited | Financial services | 1991 |
| Clanbury Limited | Hospitality | 1995 |
| Clare Gardens Ltd | Real estate | 2020 |
| Claredale Warehousing Limited | Real estate | 1977 |
| Claremont Care Services Limited | Health & social care | 1971 |
| Claremont Consultancy Ltd | Professional & scientific | 1999 |
| Claremont Green Properties Limited | Real estate | 2005 |
| Clarity Limited | Financial services | 1997 |
| Clarity Recruitment | | 2002 |
| Clarke Commercial Services Limited | Administrative & support | 2005 |
| Clarke Gammon (Haslemere) Limited | Real estate | 2002 |
| Claro Media Limited | Arts & recreation | 2002 |
| Classic Beaute Limited | Wholesale & retail | 1996 |
| Classic Concerts Trust | Arts & recreation | 1986 |
| Classic Fabrics & Stylish Antiques Limited | Wholesale & retail | 1996 |
| Classic WOK Ltd | Hospitality | 2019 |
| Claygate News Limited | Wholesale & retail | 2005 |
| Claygate Travel Limited | Administrative & support | 1987 |
| Claymore International Limited | Information & communication | 2002 |
| Clayton Electrical Limited | Construction | 1995 |
| Clayton Trading Limited | Financial services | 2022 |
| CLB Financial Advisors Limited | Financial services | 2002 |
| CLB Financial Consulting Limited | Administrative & support | 2002 |
| Cleadale Consulting Limited | Professional & scientific | 2007 |
| Cleeve Management Limited | Households | 1986 |
| Clemo Gray Investments Ltd | Construction | 2021 |
| Clerkenwell Green Property Management Limited | Real estate | 1980 |
| Clifford Partitioning Company Limited | Construction | 1979 |
| Clive Christian Weybridge Limited | Wholesale & retail | 1995 |
| Cloden Consulting Limited | Information & communication | 2007 |
| Clonmore Street Investments Limited | Real estate | 2007 |
| Clouds END Services Ltd | Administrative & support | 2011 |
| Clough Smith Ltd | Construction | 2004 |
| Cloveline Limited | Professional & scientific | 1988 |
| CLR Estates Ltd | Households | 2020 |
| CM Health Solutions Limited | Professional & scientific | 2003 |
| CMC Ltd. | Construction | 1987 |
| CNG Fast Food Ltd | Hospitality | 2021 |
| Cnut Archetype Limited | Information & communication | 1996 |
| Coaching Professionals Limited | Professional & scientific | 2004 |
| Coast Activities Limited | Professional & scientific | 2005 |
| COB Property Investments Limited | Real estate | 1989 |
| Cobham Commodity Consulting Limited | Professional & scientific | 2002 |
| Cobham Properties Limited | Real estate | 2005 |
| Codelytica Digital Technologies Ltd | Information & communication | 2022 |
| Cody Construct Ltd | Construction | 2024 |
| Cogito Development Projects Limited | Education | 2003 |
| Coherence Enhancement Training Systems Limited | Other services | 2004 |
| Coign Limited | Professional & scientific | 2002 |
| Coldfyre Limited | Professional & scientific | 2002 |
| Colgate-Palmolive UK Group Limited | Administrative & support | 2024 |
| Collaborative Insight Technologies Limited | Information & communication | 2005 |
| College of ST. Barnabas(The) | Hospitality | 1899 |
| Collett Property Management Limited | Real estate | 2020 |
| Colley Wood Syndicate,Limited(The) | Real estate | 1925 |
| Collier Contracts Limited | Construction | 1985 |
| Collingwood-Batchellor Limited | Wholesale & retail | 1966 |
| Colmac Enterprises Limited | Hospitality | 2002 |
| Colorfax Limited | | 1966 |
| Colourmatch Decorator Centre Limited | Construction | 2004 |
| Colville Gardens Management Company Limited | Households | 1990 |
| Colwayne Limited | Real estate | 1991 |
| Comar Line Limited | Financial services | 1935 |
| Comebounty Ltd | Hospitality | 2006 |
| Commercial Bookkeeping Ltd | Professional & scientific | 2007 |
| Commercial Insurance Services Limited | Financial services | 1997 |
| Commodity Partners Limited | Extraterritorial | 1996 |
| Communication Marketing Services Limited | Real estate | 1999 |
| Company Officer Limited | Administrative & support | 2001 |
| Compassion in World Farming (Trading Company) Limited | Other services | 1994 |
| Compassion in World Farming International | Other services | 2002 |
| Compassion in World Farming Supporters | Other services | 1992 |
| Compequip Limited | | 1984 |
| Complete Electrical Solutions Limited | Construction | 2003 |
| Complete Mortgages Limited | Administrative & support | 2005 |
| Complete Property Care Limited | Administrative & support | 1999 |
| Completions Limited | Construction | 1999 |
| Computamatrix Limited | Information & communication | 1994 |
| Computek Services Limited | Information & communication | 1996 |
| Computer Bi.T Solutions Limited | Information & communication | 1998 |