| Clairmount Investment Limited | Professional & scientific | 2024 |
| Clancy Advisory Limited | Professional & scientific | 2024 |
| Clarence Mill Limited | Construction | 1999 |
| Claret & CRU Ltd | Extraterritorial | 2011 |
| Clarion Holdings Limited | Real estate | 2000 |
| Clarion Water Limited | Manufacturing | 2013 |
| Clarity Point Group Ltd | Professional & scientific | 2026 |
| Clarity Tree Limited | Administrative & support | 2020 |
| Clark Daniel Travel Limited | Administrative & support | 2025 |
| Clas Houses Limited | Real estate | 2016 |
| Class and Culture Films Ltd | Information & communication | 2024 |
| Classic Building Services (Cheshire) Ltd | Construction | 2012 |
| Classic Claret Limited | Extraterritorial | 2007 |
| Classic Moto Limited | Wholesale & retail | 2015 |
| Classicar Automotive Limited | Wholesale & retail | 2002 |
| Classworx Holdings Limited | Financial services | 2026 |
| Classworx Limited | Wholesale & retail | 2017 |
| Clayton Property Group Limited | Real estate | 2015 |
| Clean Assured Limited | Administrative & support | 2005 |
| Clean Sweep 4 U Limited | Administrative & support | 2016 |
| Clear Bridge Consultancy Limited | Professional & scientific | 2021 |
| Clearline Telecom Group Ltd | Information & communication | 2026 |
| Clearscope Properties Limited | Real estate | 2024 |
| Cledan Developments Limited | Construction | 2002 |
| Clewley Sweepers Limited | Administrative & support | 2009 |
| Clewley Truck Repairs Limited | Manufacturing | 2020 |
| Click & Ship Express Ltd | Transport & logistics | 2025 |
| Client Experience Limited | Professional & scientific | 2019 |
| Cliff Hollins Farm Stays Limited | Hospitality | 2024 |
| Cliff Hollins Services Ltd | Agriculture & fishing | 2023 |
| Clifford Barca Limited | Professional & scientific | 2007 |
| Clippers of Hayfield Ltd | Other services | 2008 |
| Clix Ltd | Professional & scientific | 2019 |
| CLK Furniture Limited | Construction | 2009 |
| Cloud 9 Visualisation Ltd | Professional & scientific | 2015 |
| Cloud Network Notification & Consultancy Limited | Information & communication | 2019 |
| Cloud to Ground Ltd | Construction | 2021 |
| Cloud View Leisure Limited | Hospitality | 2014 |
| CLOUD8 Catering Limited | Hospitality | 2024 |
| Club Clothing Limited | Wholesale & retail | 2015 |
| Club House Care Group Ltd | Health & social care | 2026 |
| Club Verdé Macclesfield Ltd | Hospitality | 2025 |
| Clubaz Limited | Arts & recreation | 2010 |
| Clulow Creative Limited | Professional & scientific | 2025 |
| CM A&D Limited | Professional & scientific | 2021 |
| Cmap Global Limited | Information & communication | 2015 |
| Cmap Group Limited | Information & communication | 2015 |
| Cmap Software Limited | Information & communication | 2015 |
| Cmaxx Services Ltd | Information & communication | 2025 |
| Cnbcpo Ltd | Construction | 2025 |
| Coare Street Properties Ltd | Real estate | 2024 |
| Coast and Country Retreats Limited | Real estate | 2006 |
| Coates Spirit Ventures Ltd | Manufacturing | 2024 |
| Cobalt 24 Limited | Real estate | 2022 |
| Cobalt Cat Media Ltd | Information & communication | 2012 |
| Cocina Mexicana Limited | Hospitality | 2019 |
| Coco Deli & Catering Limited | Hospitality | 2025 |
| Cocomply Limited | Information & communication | 2019 |
| Code Nomadic Ltd | Information & communication | 2019 |
| Cogentia Healthcare Consulting Ltd | Other services | 2010 |
| Colchen Solar Limited | Energy | 2011 |
| Cole Aviation Services Limited | Professional & scientific | 2017 |
| Coleman Scientific Services Limited | Professional & scientific | 2013 |
| Colin Jackson & Sons Limited | Agriculture & fishing | 2002 |
| Colin Rotherham Design Limited | Information & communication | 2013 |
| Colla Surgical Ltd | Health & social care | 2014 |
| Collaboras Legal Limited | Professional & scientific | 2010 |
| Collaboras Legal Medical Reporting Ltd | Professional & scientific | 2017 |
| Collaborative Resolution Ltd | Professional & scientific | 2013 |
| Collect Creative Ltd | Professional & scientific | 2018 |
| Collins Care Consultancy Ltd | Health & social care | 2020 |
| Colourful Solutions (L & D) Limited | Other services | 2015 |
| Colourserve Ltd | Professional & scientific | 2006 |
| Colubris Travel Ltd | Administrative & support | 2021 |
| Colugo Limited | Professional & scientific | 2011 |
| Combrook Limited | Wholesale & retail | 2020 |
| Command Transport Ltd | Transport & logistics | 2020 |
| Commercial Consulting and Coaching Ltd | Professional & scientific | 2024 |
| Commi Holdings Limited | Information & communication | 2016 |
| Commsonaut Limited | Information & communication | 2022 |
| Compact Groundcare and Estate Machinery Ltd | Wholesale & retail | 2020 |
| Complete Insight Limited | Information & communication | 2014 |
| Complete Vehicle Maintenance Limited | Wholesale & retail | 2014 |
| Compliance & Validation Services Limited | Professional & scientific | 2009 |
| Component Center Limited | Real estate | 2007 |
| Compute Concierge Ltd | Information & communication | 2025 |
| Concept Electrical Installations Ltd | Construction | 2014 |
| Concrete Marketing Consultants Ltd | Professional & scientific | 2018 |
| Coneux Ltd | Professional & scientific | 2025 |
| Conference Engineering Limited | Information & communication | 2013 |
| Conformiti Limited | Professional & scientific | 2021 |
| Conoscenza Technology Solutions Limited | Information & communication | 2014 |
| Conscious Consultancy Limited | Extraterritorial | 2022 |
| Conscious Consultants Limited | Professional & scientific | 2013 |
| Considered IT Solutions Limited | Information & communication | 2017 |
| Considine Consultants Ltd | Professional & scientific | 2013 |
| Consilium Financial Services Limited | Financial services | 2018 |
| Consult CMG Limited | Professional & scientific | 2024 |
| Contact Tyre and Services Ltd | Wholesale & retail | 2019 |
| Context Public Relations Limited | Professional & scientific | 1998 |