| C Nellan Limited | Professional & scientific | 2018 |
| C Starling Carpentry Limited | Construction | 2012 |
| C U Logistics Limited | Transport & logistics | 2025 |
| C&A Stone Installers Limited | Construction | 2013 |
| C&C Woodfix Limited | Construction | 2021 |
| C&S Drylining Ltd | Construction | 2019 |
| C. Egbe Agbor (Resources) Limited | Arts & recreation | 2007 |
| C. Rotaru Limited | Construction | 2019 |
| C.A.Clemson & Sons Limited | Wholesale & retail | 1971 |
| C.D. Evans Plastering Ltd | Construction | 2015 |
| C.E. Broomfield Limited | Agriculture & fishing | 1945 |
| C.G.C. Property Ltd | Real estate | 2012 |
| C.G.Harrington Limited | Construction | 1935 |
| C.G.R. Polythene Company Limited | Manufacturing | 1990 |
| C.J.P Plumbing & Heating Ltd | Construction | 2007 |
| C.M. Consultancy Limited | Professional & scientific | 2020 |
| C2B Associates Ltd | Administrative & support | 2012 |
| C2G Facilities Management Limited | Professional & scientific | 2015 |
| C2G Project Service Limited | Administrative & support | 2012 |
| C3 Land & Investments Ltd | Real estate | 2021 |
| C4 Design Limited | Administrative & support | 2016 |
| Caamaj Limited | Real estate | 2025 |
| Cabby Technology Ltd | Information & communication | 2021 |
| Caber Ltd | Households | 2025 |
| Cable & Lynch Building Services Ltd | Construction | 2013 |
| Cabris Investments Ltd | Real estate | 2020 |
| Cadiz Ltd | Hospitality | 2021 |
| Cadonex Ventures Ltd | Information & communication | 2025 |
| Cadre Events Ltd | Other services | 2026 |
| Cafe DE Rumpy Limited | Hospitality | 2018 |
| Cafe Gharana Ltd | Wholesale & retail | 2025 |
| Cafe Nirvana Limited | Hospitality | 2023 |
| Cafe Questor Ltd | Hospitality | 2025 |
| Cafe Samba E14 Ltd | Hospitality | 2020 |
| Cajun Chef Ltd | Hospitality | 2017 |
| Cake Tops Ltd. | Wholesale & retail | 2013 |
| Calibre Auto Logistics Limited | Transport & logistics | 2000 |
| Calibre Forwarding Limited | Transport & logistics | 2012 |
| Calibre Logistics Limited | Transport & logistics | 2000 |
| Calibre Routex Group Limited | Transport & logistics | 1993 |
| Calibre Routex Logistics Limited | Transport & logistics | 2012 |
| Calico Charters Ltd | Other services | 2023 |
| Caligari Projects Limited | Wholesale & retail | 2021 |
| Calin Driving Ltd | Transport & logistics | 2025 |
| Calm Labtech Limited | Information & communication | 2013 |
| Calvert & Bortoli Ltd | Professional & scientific | 2016 |
| Calzip Metal Cladding Solutions Ltd. | Construction | 2016 |
| Cambridge Facilities Ltd | Other services | 2025 |
| Cambridge Roofing Specialists Limited | Construction | 2024 |
| Cambridgeshire Automatic Doors and Aluminimum Services Ltd | Manufacturing | 2017 |
| Camdeboo Properties Ltd | Real estate | 2018 |
| Camden 53 Ltd | Hospitality | 2026 |
| Camden Catering Co Ltd | Hospitality | 2014 |
| Camden Park Investments Ltd. | Financial services | 2011 |
| Cameron Clarke Care Limited | Health & social care | 2023 |
| Cameron Clarke Estate Management Limited | Real estate | 2020 |
| Cameron Clarke Property Limited | Real estate | 2023 |
| Campana Consulting Ltd. | Professional & scientific | 2005 |
| Campbell & Sons Electrical Ltd | Construction | 2026 |
| Camplings Building Surveying Consultancy Limited | Professional & scientific | 2007 |
| Cams Installations Ltd | Construction | 2017 |
| Can-Do Hire Centres Limited | Administrative & support | 1980 |
| Canada Farm Kennels Limited | Hospitality | 2014 |
| Canary Dart Financial Ltd | Administrative & support | 2016 |
| Canary Wharf Sushi Ltd | Wholesale & retail | 2025 |
| Candlelight Consultants Ltd | Education | 2016 |
| Cando Telecommunications Ltd | Information & communication | 2020 |
| Candour IT Services Limited | Information & communication | 2015 |
| Candytan Events Limited | Arts & recreation | 2018 |
| Candytan Mascots Ltd | Arts & recreation | 2024 |
| Canephora Limited | Wholesale & retail | 2024 |
| Canfields Estates (North West London) Limited | Real estate | 2018 |
| Cannon Fuel Logistics Ltd | Transport & logistics | 2024 |
| Canopy Residential Properties Limited | Real estate | 2025 |
| Canyon Homes Ltd | Construction | 2025 |
| Capable Hands Ltd | Administrative & support | 2024 |
| Cape Blue Limited | Real estate | 2000 |
| Capital Paper Recycling Limited | Professional & scientific | 1992 |
| Capital Profits Group Ltd | Real estate | 2018 |
| Capital Site Supplies Ltd | Manufacturing | 2024 |
| Capital Waste Limited | Other services | 2019 |
| Captain London Global Trading Ltd | Wholesale & retail | 2021 |
| Captivate & Educate Limited | Administrative & support | 2018 |
| Capuchin Properties Limited | Real estate | 2025 |
| Caput Energy Limited | Manufacturing | 2018 |
| Car Care Mobile Services Limited | Wholesale & retail | 2011 |
| Car Connect Kent Ltd | Wholesale & retail | 2025 |
| Carbon Cycle Tech Limited | Information & communication | 2024 |
| Care Centric Recruitment and Training Centre Ltd | Administrative & support | 2024 |
| Care Mastery Ltd | Health & social care | 2022 |
| Care With Passion Limited | Health & social care | 2023 |
| Carecoach Management Limited | Information & communication | 2014 |
| Career Transitioners Limited | Other services | 2015 |
| Carersmind CIC | Health & social care | 2025 |
| Caresphere Medical Limited | Health & social care | 2024 |
| Caricom Products Limited | Manufacturing | 2011 |
| Caringheart Homecare Ltd | Health & social care | 2020 |
| Carisma London Limited | Professional & scientific | 2016 |
| Carnaval Ltd | Hospitality | 2017 |
| Carpe Diem Entertainment Ltd | Information & communication | 2016 |