| CMS Holdings Limited | Real estate | 2001 |
| CMW Marketing Services Ltd | Administrative & support | 2021 |
| Coachable U Ltd | Professional & scientific | 2019 |
| Coaching for Growth Ltd | Professional & scientific | 2019 |
| Coco Spheres Ltd | Extraterritorial | 2024 |
| Cohort Film Services Limited | Other services | 2012 |
| Collective Connection Limited | Professional & scientific | 2026 |
| Collen Associates Ltd | Professional & scientific | 2016 |
| Colligenda Ltd | Administrative & support | 2019 |
| Colombo 7 Cinnamon Gardens Ltd | Hospitality | 2021 |
| COLOMBO7 Catering Ltd | Hospitality | 2024 |
| Colonel Property Holdings Ltd | Real estate | 2024 |
| Comfast Limited | Professional & scientific | 1971 |
| Comfit Fitness Limited | Arts & recreation | 2025 |
| Command Training Solutions Ltd. | Education | 2012 |
| Commerixx Ltd | Wholesale & retail | 2025 |
| Commodities Analysis and Insight Ltd | Professional & scientific | 2018 |
| Community Access Health Ltd | Health & social care | 2023 |
| Community Youth Ventures C.I.C. | Public administration | 2018 |
| Compact Spare Wheel Limited | Wholesale & retail | 2026 |
| Compound Leadership Group Ltd | Professional & scientific | 2022 |
| Coney and Naylors Spring Wood Ltd | Agriculture & fishing | 2016 |
| Connected Electrical & Lighting Ltd | Construction | 2011 |
| Consortium Corporate Holdings Limited | Professional & scientific | 2008 |
| Consortium Directors Limited | Professional & scientific | 2008 |
| Consortium Investment Management LLP | | 2007 |
| Consortium NO 1 Limited | Professional & scientific | 2008 |
| Consortium NO 2 Limited | Professional & scientific | 2006 |
| Consortium Nominees NO 1 Limited | Professional & scientific | 2011 |
| Consortium Nominees NO 2 Limited | Professional & scientific | 2011 |
| Consortium Property Venture Fund General Partner NO 1 Limited | Administrative & support | 2006 |
| Consortium Property Venture Fund NO. 1 LP | | 2007 |
| Consortium Security Trustee Limited | Professional & scientific | 2013 |
| Constech Limited | Professional & scientific | 2005 |
| Construx Trade Ltd | Construction | 2024 |
| Consultants Direct Limited | Professional & scientific | 2006 |
| Contrarian Investments Ltd | Information & communication | 2019 |
| Convalia Health Limited | Health & social care | 2018 |
| Cook Properties Limited | Real estate | 2021 |
| Cordelia Mali Ltd | Information & communication | 2024 |
| Core Fitness Amersham Limited | Other services | 2016 |
| Corhaven Medical Equipment Trading Ltd | Wholesale & retail | 2022 |
| Corixa Group Holdings Limited | Financial services | 2024 |
| Corixa Limited | Professional & scientific | 2012 |
| Cork Holdings Limited | Real estate | 2016 |
| Corleone Consulting Ltd | Professional & scientific | 2007 |
| Corporate Communication Centre Limited | Information & communication | 2000 |
| Corporate Narrative Ltd | Professional & scientific | 2025 |
| Cosmic Microwave Limited | Professional & scientific | 2024 |
| Cosmiq Beauty Ltd | Other services | 2026 |
| Cosy Roof and Property Maintenance Ltd | Other services | 2024 |
| Cotswold Lease Hire Limited | Manufacturing | 1998 |
| Coulton Cars Limited | Transport & logistics | 2025 |
| Coventry Hood & Tonneau Limited | Wholesale & retail | 2004 |
| Coyle Read Football Agency Limited | Arts & recreation | 2024 |
| Coyle White Devine Limited | Professional & scientific | 2010 |
| CPC Performance Engineering Limited | Wholesale & retail | 2006 |
| Crafty Squirrel Limited | Real estate | 2019 |
| Crawshay Films Ltd | Information & communication | 2017 |
| Crazy Kippax Limited | Administrative & support | 2012 |
| CRB Motor Service Limited | Wholesale & retail | 2018 |
| Creative by Nature Design Limited | Professional & scientific | 2020 |
| Creative Land Limited | Real estate | 2010 |
| Creative Media Systems Limited | Information & communication | 2016 |
| Creative Synergy Limited | Real estate | 1984 |
| Creffield Advisory Limited | Information & communication | 2022 |
| Critical Path Ltd | Extraterritorial | 2022 |
| Croftedge Marketing Limited | Professional & scientific | 2013 |
| Crofters Homes Ltd | Real estate | 2026 |
| Crolvale Limited | Real estate | 1978 |
| Cromptons Interiors Limited | Wholesale & retail | 2012 |
| Crunch Date Limited | Information & communication | 2026 |
| Csense PR Ltd | Professional & scientific | 2021 |
| Ctrl+Shift+T Limited | Administrative & support | 2013 |
| Cube Tax Accountants Ltd | Professional & scientific | 2021 |
| CUE34 Theatre Company Ltd | Arts & recreation | 2021 |
| Culinera Limited | Hospitality | 2020 |
| Culley Associates Ltd | Information & communication | 2014 |
| CUP Communications Ltd | Wholesale & retail | 2022 |
| Curry Crazy (Amersham) Ltd | Hospitality | 2024 |
| Curve Contracting Ltd | Construction | 2020 |
| CUT & Create Ltd | Manufacturing | 2019 |
| CWG Advisory Limited | Other services | 2022 |
| CYL Meng House Ltd | Hospitality | 2017 |
| Cymatec Ltd | Professional & scientific | 2022 |
| D & L Contracts Limited | Professional & scientific | 2018 |
| D and M Channer Limited | Agriculture & fishing | 2022 |
| D M K Croos Limited | Wholesale & retail | 2024 |
| D&T Property Services Ltd | Real estate | 2017 |
| D.Bagmet Ltd | Information & communication | 2023 |
| D.H Loveday and SON Limited | Wholesale & retail | 2006 |
| Dabble Art Ltd | Education | 2025 |
| Daksh Services Ltd | Financial services | 2023 |
| Dale House Developments Ltd | Real estate | 2013 |
| Dalyndo International Limited | Extraterritorial | 1987 |
| Damiano Paving and Landscaping Ltd | Administrative & support | 2019 |
| Danale Ltd | Professional & scientific | 2024 |
| Danichris Limited | Professional & scientific | 2011 |
| Darcy Burke Properties LLP | | 2013 |
| Dare Properties Limited | Real estate | 2025 |