| CGX Training Solutions Limited | Professional & scientific | 2026 |
| Chabees Ltd | Wholesale & retail | 2020 |
| Chadha Properties Ltd | Real estate | 2016 |
| Chagos Islanders Movement Non-Profit Organisation Limited | Education | 2018 |
| Channel Parking Limited | Other services | 2018 |
| Channex Holdings Limited | Other services | 2018 |
| Channex Limited | Other services | 2016 |
| Channex Project Management Limited | Other services | 2019 |
| Channex Properties Limited | Other services | 2016 |
| Channex Services Limited | Other services | 2016 |
| Channex South Limited | Financial services | 2023 |
| Charles Fraser Fleming Limited | Administrative & support | 1995 |
| Charlotte of London (Aphrodite) Ltd | Other services | 2014 |
| Charlotte of London Limited | Other services | 2008 |
| Charnleigh Gate (Purley) Management Limited | Households | 2006 |
| Charteris Asset Management Ltd | Financial services | 2024 |
| Chatsworth Mansions Limited | Real estate | 2013 |
| Cherry Blossom Purley Limited TA ZEN Lounge Ltd | Hospitality | 2019 |
| China City (Purley) Ltd | Hospitality | 2019 |
| Choja Ltd | Administrative & support | 2015 |
| Chrisbrownconsulting Ltd. | Professional & scientific | 2026 |
| Christchurch Road Residents Association Limited | Households | 1977 |
| Christiansborg Heritage Initiative Limited | Hospitality | 2018 |
| Chta Limited | Education | 2014 |
| Churchill Care Home Limited | Health & social care | 2016 |
| Circle of Giving C.I.C. | Education | 2025 |
| Circuit Electrical Services Ltd | Administrative & support | 2017 |
| Circulogue Ltd | Information & communication | 2025 |
| City Roofing Contractors Limited | Construction | 2020 |
| City Vehicle Hire Limited | Administrative & support | 2011 |
| Civil Engineering Dynamics Ltd | Extraterritorial | 2025 |
| Civio Property Ltd | Real estate | 2026 |
| Civiva CIC | Professional & scientific | 2025 |
| CKS United Ltd | Information & communication | 2025 |
| Claremont & ST James Leasehold Limited | Real estate | 2025 |
| Claremont & ST James Limited | Construction | 2023 |
| Claremont Gardens Ltd | Construction | 2016 |
| Clareville Homes Limited | Financial services | 1986 |
| Clarshire Holdings Ltd | Financial services | 2026 |
| Clarshire Limited | Wholesale & retail | 1971 |
| Claudiu Voicu Ltd | Information & communication | 2013 |
| Clavis Aditum Limited | Education | 2015 |
| Cleaningday Ltd | Administrative & support | 2018 |
| Clear OUT Move OUT Ltd | Transport & logistics | 2026 |
| Clearplan Associates Limited | Other services | 1989 |
| Cliffend Consultancy Services Limited | Professional & scientific | 2012 |
| Clinnovate Ltd | Health & social care | 2015 |
| Close Ridge Services Limited | Professional & scientific | 2013 |
| Coalition Brewing Company Ltd | Manufacturing | 2015 |
| Coconella Hair & Beauty Ltd | Other services | 2022 |
| Code Warriors Limited | Education | 2022 |
| Coffey Summers Limited | Administrative & support | 2023 |
| Cohak Limited | Information & communication | 2013 |
| Colere Limited | Wholesale & retail | 2025 |
| Collaborative One Limited | Construction | 2022 |
| Colorful Standard UK Limited | Wholesale & retail | 2023 |
| Coltrane Property Services Ltd | Construction | 2021 |
| Commonweal Lodge Management Company Limited | Households | 2017 |
| Comparatus Ltd | Professional & scientific | 2010 |
| Complete London Builders Limited | Construction | 2011 |
| Compound Growth Limited | Professional & scientific | 2011 |
| Comprehensive Consultancy Limited | Construction | 2017 |
| CON O'Donovan Ltd | Transport & logistics | 2023 |
| Concal Projects Limited | Construction | 2011 |
| Concepto CN Limited | Education | 2023 |
| Concerned Leaseholders Old Lodge Lane Ltd | Real estate | 2024 |
| Connect GAS Ltd | Construction | 2013 |
| Connex Holding Ltd | Administrative & support | 2011 |
| Construccion Rapida Ltd | Construction | 2022 |
| Construction JOB Training Services Ltd | Administrative & support | 2024 |
| Consulting MEE Ltd | Information & communication | 2022 |
| Contracting Consultant Services Ltd | Administrative & support | 2011 |
| Convivial Consulting Ltd | Information & communication | 2022 |
| Cook Square Limited | Real estate | 2018 |
| Cool Ice (South East) Limited | Manufacturing | 2021 |
| Cool Play and Feifan Group Ltd | Wholesale & retail | 2025 |
| Cooper Property Investments Ltd | Real estate | 2014 |
| Corina House RTM Company Limited | Extraterritorial | 2025 |
| Cornells Garden Machinery Limited | Manufacturing | 2025 |
| Cornerstone Accountants and Consultants Limited | Professional & scientific | 2024 |
| Cortium EQ Limited | Other services | 2022 |
| Cortium Holdings Limited | Financial services | 2020 |
| Cortium Sports Limited | Arts & recreation | 2011 |
| COS Truro Limited | Wholesale & retail | 2019 |
| Coshan Limited | Other services | 2022 |
| Cosmaesthetics Academy Limited | Education | 2024 |
| Cottle Limited | Real estate | 2014 |
| Countrywide Essentials Ltd | Wholesale & retail | 2024 |
| Counts Football Limited | Education | 2026 |
| Courtmanbrickwork & Development Services Ltd | Construction | 2023 |
| CPH Music Limited | Information & communication | 2024 |
| Craig Newsome Consulting Limited | Professional & scientific | 2026 |
| Craig Property Ltd | Real estate | 2015 |
| Cray Hill Limited | Wholesale & retail | 2026 |
| Creamy Palace Limited | Hospitality | 2019 |
| Crentsil Property Group Ltd | Real estate | 2025 |
| Crest Technical Services Limited | Mining & quarrying | 1989 |
| Crest Technical Services London Limited | Extraterritorial | 2016 |
| CRN Consulting Ltd | Professional & scientific | 2019 |
| Crossland Audio Ltd | Construction | 2022 |