| C.L.Eaglen & Company Limited | Cambridge | 1958 |
| C.L.S.H Ltd | Durham | 2012 |
| C.L.T.C. Ltd | Sidcup | 2005 |
| C.M. Wettern Limited | Lewes | 1960 |
| C.O.Tilney Limited | Hertford | 1946 |
| C.P. Electronics Limited | Birmingham | 1971 |
| C.R. Smith (Aluminium) Limited | Dunfermline | 1979 |
| C.R.I. Limited | Southport | 1999 |
| C.R.P. Securities Limited | Tewkesbury | 1998 |
| C.S. North Ltd | Sutton Coldfield | 2008 |
| C.T. Shetland (T.M.) Limited | Shetland | 1980 |
| C.U.F.C. Holdings Limited | Carlisle | 1992 |
| C.V. Gauges Limited | Sheffield | 1999 |
| C.W. JOE Limited | Harpenden | 2023 |
| C.Y. Star Enterprise Limited | London | 2010 |
| C2 International Partners Limited | London | 2012 |
| C2E Energy Limited | Rushden | 2025 |
| C2M Management Ltd | Edinburgh | 2012 |
| C3 Employee Ownership Trustee Ltd | London | 2022 |
| C4 Distribution Limited | Coventry | 2006 |
| C4 Industries Limited | Manchester | 2002 |
| C4 Logistics (Express) Limited | Coventry | 2006 |
| C4C SIP Trustee Limited | Stone | 2016 |
| C4SH Ltd | Harrogate | 2017 |
| C5T & Company Limited | London | 2014 |
| C7 Yachting Ltd | London | 2024 |
| CA DI Rajo Wines UK Ltd | London | 2022 |
| CA Investment Management Ltd | Coventry | 2015 |
| CA Property Investments Ltd | Hemel Hempstead | 2015 |
| Ca$H Ltd | Harrogate | 2015 |
| Ca$Ino Ltd | Harrogate | 2015 |
| Caai Ltd | London | 2016 |
| Caam Management Ltd | Wokingham | 2011 |
| Caaps Trustee Limited | London | 2012 |
| CAB (NO. 1) Limited | London | 1995 |
| CAB Direct Limited | Lanarkshire | 2004 |
| CAB Roofing Supplies (Marley) Ltd | Wick | 2024 |
| Cabana Studios Ltd | London | 2016 |
| Cabbie Cars Ltd | London | 2024 |
| Cabcal Services Limited | Redditch | 2002 |
| Cabcare Limited | Stafford | 2004 |
| Cabernet Investment Ltd. | London | 2019 |
| Cabigo Limited | Pevensey Bay | 2016 |
| Cabin Care Limited | London | 2023 |
| Cabinet Veterinaire Detry Ltd | Dover | 2018 |
| Cabinq Limited | Cheadle | 2016 |
| Cabins 4 Sale Limited | Portishead | 2012 |
| Cabins Limited | Bath | 1988 |
| Cable & Wireless Services UK Limited | London | 1999 |
| Cable Accessories Limited | Sawbridgeworth | 1996 |
| Cable and Wifi Limited | Harrogate | 2013 |
| Cable Financial Directions Limited | Truro | 2003 |
| Cable Installation Services Limited | Preston | 2024 |
| Cable Jointers Ltd | Warrington | 2024 |
| Cable Products Limited | Basingstoke | 1991 |
| Cable Tray (UK) Limited | Hednesford | 2008 |
| Cableandsocket.Co.Uk Limited | Leigh-On-Sea | 2018 |
| Cableplough Ltd | Swansea | 2016 |
| Cablerange Limited | Norwich | 2010 |
| Cablesheer Environmental Ltd | Sidcup | 2012 |
| Cablesheer Projects Ltd | Sevenoaks | 2014 |
| Cablestore Limited | Colchester | 2022 |
| Cabletec Interconnect Components Systems Limited | London | 1988 |
| Cabletel Surrey and Hampshire Limited | Reading | 1992 |
| Cablezone Limited | Northwood | 2003 |
| Cabling Technologies Limited | Sidcup | 2009 |
| Cabmasters Limited | Rossendale | 2000 |
| Caboncaï Products Ltd | London | 2015 |
| Caboodle Office Supplies Limited | Southampton | 2026 |
| Cabot Financial (International) Limited | West Malling | 1998 |
| Cabot Industries Ltd | Doncaster | 2012 |
| Cabot Park Management Limited | Bristol | 1998 |
| Cabot Systems Limited | Gloucestershire | 2004 |
| Cabs Direct Limited | Lanarkshire | 2004 |
| Cabsurance Limited | London | 1983 |
| Cabtec Ltd | Rotherham | 2012 |
| Caburn SPV 1 Limited | Brighton | 2026 |
| Caburn SPV 2 Limited | Brighton | 2026 |
| Caburn SPV 3 Limited | Brighton | 2026 |
| Cacao London Ltd | London | 2012 |
| Cachee Investment Limited | London | 2021 |
| Cachesure Ltd | Tonbridge | 2012 |
| Cachi Foods Limited | Belfast | 2014 |
| Cachnacruidh Gundogs Ltd | Fochabers | 2024 |
| Cacique Investments Limited | Aylesbury | 2017 |
| Caco&Co Blackfriars Limited | London | 2016 |
| Cactus Marine Ltd | London | 2020 |
| Cactus Recruitment Limited | Cambridge | 2021 |
| CAD 3D Limited | Nottingham | 1995 |
| CAD CAM Create Limited | Slinfold, Horsham | 2025 |
| CAD Coordination Services Limited | Essex | 2003 |
| CAD Drafting Services Limited | Essex | 2003 |
| CAD Link Services Limited | Essex | 2003 |
| CAD Project Services Limited | Essex | 2003 |
| CAD Surveying Limited | Essex | 2003 |
| CAD Surveying Services Limited | Essex | 2003 |
| CAD Systems Limited | Hatfield | 1984 |
| CAD Technical Services Limited | Essex | 2005 |
| CAD Tracing Limited | Essex | 2003 |
| CAD Tracing Services Limited | Essex | 2003 |