| Clearpearl Limited | Real estate | 2024 |
| Clearstone Facilities Group Limited | Administrative & support | 2026 |
| Clearstrat Management Consultancy Limited | Professional & scientific | 2014 |
| Clearview Global Ltd | Wholesale & retail | 2025 |
| Clearview Vehicles Services Limited | Wholesale & retail | 2025 |
| CLF Art Lounge Ltd | Administrative & support | 2014 |
| Click to Rent Limited | Real estate | 2019 |
| Clifton Court Limited | Real estate | 2019 |
| Clifton Traders (UK) Limited | Wholesale & retail | 2006 |
| Clique London Limited | Wholesale & retail | 2019 |
| Clock House Gardens Management Limited | Households | 2014 |
| Clockwork Labs Limited | Professional & scientific | 2026 |
| Cloth Shop Limited(The) | Wholesale & retail | 1982 |
| Cloud Chip IT Solutions Ltd | Wholesale & retail | 2025 |
| Cloud Kitchen London Ltd | Hospitality | 2020 |
| Cloud Technology Group Limited | Information & communication | 2021 |
| Cloudex Consulting Limited | Information & communication | 2019 |
| Cloudgene Solutions Limited | Information & communication | 2018 |
| Cloudreason Limited | Information & communication | 2016 |
| CM4 Autos Ltd | Wholesale & retail | 2022 |
| CMB Accounting Services Ltd | Professional & scientific | 2012 |
| CMB Property Group Ltd | Administrative & support | 2021 |
| CMC PA Academy Limited | Education | 2016 |
| CMC Performing Arts LLP | | 2022 |
| CMG Surveys Ltd | Construction | 2016 |
| CMR MAX Limited | Administrative & support | 2014 |
| CN Consultancy PVT Ltd | Education | 2026 |
| CN Direction Ltd | Professional & scientific | 2016 |
| Co-Axe Limited | Administrative & support | 2011 |
| Coach Brusk Ltd | Administrative & support | 2021 |
| Coach Conor Limited | Arts & recreation | 2023 |
| Coam Consulting Ltd | Professional & scientific | 2026 |
| Coco Pink Swimwear Limited | Administrative & support | 2019 |
| Coconaya Limited | Manufacturing | 2021 |
| Cocoon International Limited | Administrative & support | 2017 |
| Code Black Limited | Administrative & support | 2010 |
| Code Grey Publishing Limited | Information & communication | 2021 |
| Code Security Systems Limited | Administrative & support | 2005 |
| Coding Specialists Ltd | Information & communication | 2016 |
| Coffee Export Ltd | Manufacturing | 2024 |
| Coffee Loughtone Ltd | Hospitality | 2022 |
| Cogito Company Services Limited | Administrative & support | 2008 |
| Cognumi Ltd | Wholesale & retail | 2026 |
| Coherent Consulting Ltd | Information & communication | 2010 |
| Colar & Sons Ltd | Construction | 2022 |
| Colar Management Limited | Professional & scientific | 2016 |
| Cold Unit Ltd | Wholesale & retail | 2025 |
| Coldrum Homes (Tenterden) Ltd | Construction | 2018 |
| Coldrum Homes (Windsor Works) Limited | Real estate | 2018 |
| Coldrum Homes Limited | Administrative & support | 2018 |
| Coleman Projects Limited | Transport & logistics | 2003 |
| Collective Dynamics Limited | Manufacturing | 2014 |
| Collins Cartons Limited | Real estate | 1976 |
| Colour Nail Bar (BG) Limited | Other services | 2019 |
| Colworth Road Venue Limited | Arts & recreation | 2010 |
| Combo Innovation Ltd | Information & communication | 2020 |
| Comet Music Limited | Administrative & support | 2012 |
| Comfort Zone 226 Limited | Real estate | 2025 |
| Commercial Futures Limited | Professional & scientific | 2022 |
| Commercial Lawyers Limited | Professional & scientific | 2020 |
| Commnetsolutions Limited | Information & communication | 2012 |
| Community Corporate and Culture Group C.I.C. | Health & social care | 2024 |
| Compdir Marine Limited | Extraterritorial | 1998 |
| Complete Civil (Utilities) Ltd | Administrative & support | 2024 |
| Complete Licensing Limited | Professional & scientific | 2020 |
| Complete Security Recruitment Limited | Administrative & support | 2005 |
| Compliance Resolutions Limited | Professional & scientific | 2021 |
| Compliance Risk & Advisory Limited | Professional & scientific | 2006 |
| Compoly Limited | Information & communication | 2010 |
| Compsec Marine Limited | Extraterritorial | 1978 |
| Concat AI Limited | Information & communication | 2023 |
| Concept 360 London Ltd | Construction | 2024 |
| Concept Key Limited | Information & communication | 2015 |
| Condor Structuring Ltd | Extraterritorial | 2025 |
| Coney Construction Services Limited | Construction | 2017 |
| Congregation Sharei Sholom Tchabe Limited | Education | 2006 |
| Connaught House Consulting Limited | Financial services | 2013 |
| Connectto Ltd | Other services | 2022 |
| Conquest Shipping Limited | Transport & logistics | 1990 |
| Conrad Properties Ltd | Real estate | 2015 |
| Constantin Couriers Ltd | Transport & logistics | 2024 |
| CONSTRUCT4LIFE Ltd | Construction | 2021 |
| Consultant Community Ltd | Administrative & support | 2020 |
| Contemporary Architecture Ltd | Construction | 2008 |
| Contemporary Tailors Limited | Professional & scientific | 2009 |
| Content Equity Ltd | Professional & scientific | 2025 |
| Contour Planning Consultants Ltd | Professional & scientific | 2026 |
| Controls Design Limited | Administrative & support | 2024 |
| Conway IT Services Limited | Information & communication | 2001 |
| Cook Fundraising Consultancy Ltd | Financial services | 2014 |
| Cook Property Management Limited | Real estate | 2001 |
| Cool to Clean Ltd | Administrative & support | 2011 |
| Cooley Home Studio Ltd | Professional & scientific | 2013 |
| Cooper Young & Partners Ltd | Professional & scientific | 2014 |
| Copper Bath Company Ltd | Wholesale & retail | 2024 |
| Corevia Biotics Ltd | Information & communication | 2023 |
| Corex London Ltd | Construction | 2018 |
| Corley Bros.(Builders)Limited | Real estate | 1943 |
| Corley Property Management Limited | Real estate | 2006 |
| Cornerstone Coffee Shop Ltd | Hospitality | 2019 |