| C a Services P&H Ltd | Construction | 2017 |
| C H Security Systems Limited | Administrative & support | 2015 |
| C J Architectural Design Services Ltd | Professional & scientific | 2016 |
| C J Cosyhome Ltd | Construction | 2023 |
| C&C Plumbing Factory Limited | Construction | 2015 |
| C. Mana Mediagest Ltd | Wholesale & retail | 2026 |
| C.D.G. Construction Limited | Construction | 1996 |
| C.K. Tiling Limited | Construction | 2002 |
| C24CARE Ltd | Health & social care | 2025 |
| Cadogan Property Limited | Real estate | 2013 |
| Cafe Concerto Limited | Hospitality | 2010 |
| Cafe Plaza (Kent) Limited | Wholesale & retail | 2013 |
| Cahill Networks Limited | Other services | 2021 |
| Cain Consultants LLP | | 2023 |
| CAL Mccrystal Limited | Arts & recreation | 2012 |
| Caldecote Developments Ltd | Construction | 2023 |
| Camino Collective Holdings Ltd | Financial services | 2024 |
| CAN Chill Properties Ltd | Real estate | 2022 |
| Canna Ltd | Real estate | 2024 |
| CAP Railway Limited | Construction | 2019 |
| Capability Employment Bureau Limited | Professional & scientific | 2002 |
| Capable Canines Ltd | Education | 2024 |
| Capacity+ Ltd | Health & social care | 2026 |
| Capellie Ltd | Other services | 2023 |
| Capital a Limited | Wholesale & retail | 2009 |
| Capital Heating & Plumbing Services Limited | Manufacturing | 2016 |
| Capital Masonry Limited | Construction | 2015 |
| Capital Property Investment (SE) Ltd | Financial services | 2024 |
| Care Automobile Repair Limited | Wholesale & retail | 2017 |
| Carey Court Management Company Limited | Real estate | 1982 |
| Caribitos Ltd | Extraterritorial | 2012 |
| Carl M. Sutton Limited | Construction | 2008 |
| Carlingford Residents Limited | Households | 1982 |
| Carlton Place (Sidcup) Management Company Limited | Households | 2006 |
| Carlyle Properties Ltd | Real estate | 2023 |
| Carmonn LLP | | 2026 |
| Caroline Lindesay Consultants UK Ltd | Health & social care | 2023 |
| Carrac Limited | Professional & scientific | 2014 |
| Carrington Rose Limited | Professional & scientific | 2002 |
| Carte Blanche Interiors Ltd | Wholesale & retail | 2025 |
| Carter Investments Limited | Professional & scientific | 2021 |
| Casidor Consulting Ltd | Information & communication | 2019 |
| Casterton Care Group Limited | Health & social care | 2021 |
| Casterton Care Homes Limited | Real estate | 2022 |
| Castle Improvements Ltd. | Construction | 2013 |
| Cat Great Limited | Information & communication | 2026 |
| Cataa Solutions Ltd | Construction | 2024 |
| Caterham Engineering Limited | Professional & scientific | 2016 |
| Catering Materials Handling Ltd | Manufacturing | 2024 |
| Catherine Hastings Interiors Ltd | Professional & scientific | 2013 |
| Cators Limited | Wholesale & retail | 2021 |
| Cavallsoft Ltd | Information & communication | 2015 |
| CD Capital Properties Ltd | Construction | 2022 |
| CDL Exterior Cleaning Services Limited | Administrative & support | 2021 |
| Cdmw Limited | Professional & scientific | 2025 |
| Celeste Film Ltd | Information & communication | 2025 |
| Celsys UK Ltd | Wholesale & retail | 2025 |
| Central Health Group Ltd | Wholesale & retail | 2023 |
| Cerulean D&C Ltd | Other services | 2021 |
| Chamberlain Bexley Limited | Real estate | 2003 |
| Chamberlain Tickner Limited | Real estate | 2006 |
| Champers (Retail) Limited | Wholesale & retail | 2006 |
| Champers Group Limited | Wholesale & retail | 2007 |
| Chapman HR Consulting & Solutions Ltd | Administrative & support | 2025 |
| Charge Evolution Ltd | Construction | 2022 |
| Charis HGA Properties Limited | Information & communication | 2024 |
| Charles Parker Consultants Ltd | Professional & scientific | 2026 |
| Charlie's Angels Parties Ltd | Other services | 2020 |
| Charlotte Dawkins Consulting Ltd | Administrative & support | 2017 |
| Charnwood Builders Limited | Construction | 1961 |
| Charnwood Builders Orpington Ltd | Construction | 2016 |
| Charsola Creative Management Ltd | Professional & scientific | 2025 |
| Charters UK Limited | Administrative & support | 2009 |
| Chase HS Ltd | Wholesale & retail | 2025 |
| Chelsfield Glass Limited | Administrative & support | 2004 |
| Chicken LEG Ltd | Arts & recreation | 2010 |
| Chigwell Auto Spares Ltd | Wholesale & retail | 2024 |
| Chiltern Green Homes Limited | Construction | 2014 |
| Chislehurst Plumbers Ltd | Construction | 2019 |
| Chitatyam Limited | Real estate | 2024 |
| CHL Limited | Wholesale & retail | 1986 |
| Chotech Solutions Ltd | Information & communication | 2025 |
| Chris Lang Estates Ltd | Real estate | 2022 |
| Christina Cornwell Ltd | Professional & scientific | 2022 |
| Christopher-K Ltd | Information & communication | 2025 |
| Chuo-Nittochi UK Ltd | Financial services | 2026 |
| Ciberts Ltd | Information & communication | 2023 |
| Cibertsai Ltd | Information & communication | 2023 |
| Cillion Consulting Limited | Financial services | 2017 |
| Circuitry Auto Ltd | Wholesale & retail | 2023 |
| City South Construction Ltd | Construction | 2009 |
| City View Management Company Limited | Households | 1989 |
| Cityline Holdings Limited | Construction | 2021 |
| Cityline Security Limited | Administrative & support | 2006 |
| Citysafe Limited | Professional & scientific | 2026 |
| CJ Alarms Limited | Administrative & support | 2026 |
| CJ Services Ltd Ltd | Transport & logistics | 2026 |
| CJL Burton Investments Limited | Real estate | 2025 |
| CJP Services Ltd | Construction | 2024 |
| CL Capital Investments Limited | Real estate | 2022 |