| Cloverquest Ltd | Education | 2025 |
| CLT Advisory Ltd. | Information & communication | 2014 |
| CLT Investment Ltd. | Real estate | 2013 |
| Clyde Care Limited | Health & social care | 2016 |
| Clyn London Ltd | Wholesale & retail | 2026 |
| CMA Fire Assistance Ltd | Public administration | 2024 |
| CMA Property Limited | Real estate | 2016 |
| Cmgm Limited | Other services | 2001 |
| CNC Carpentry LLP | | 2020 |
| Coach Centered Ltd. | Education | 2019 |
| Coads LLP | | 2008 |
| Cochrane Design 6 Limited | Real estate | 2018 |
| Cockfield Garage Ltd | Wholesale & retail | 2015 |
| COD Bay Traditional Ltd | Hospitality | 2023 |
| Code Meadow Limited | Information & communication | 2025 |
| Codezest Ltd | Information & communication | 2008 |
| Coding Bear Ltd | Information & communication | 2026 |
| Cognus Limited | Education | 2016 |
| Cogscape Limited | Information & communication | 2021 |
| Colicci Limited | Hospitality | 2014 |
| Colkara Care and Support Ltd | Administrative & support | 2021 |
| Collective Agents Ltd | Administrative & support | 2020 |
| Collingwood School Educational Trust Limited | Education | 1978 |
| Combinext Limited | Wholesale & retail | 2025 |
| Comfortzone Rentals Limited | Hospitality | 2024 |
| Commonwealth Citizens Limited | Wholesale & retail | 2021 |
| Compass Care Support Ltd | Health & social care | 2025 |
| Complete Care Consultancy Limited | Information & communication | 2006 |
| Comptus Ltd | Information & communication | 2018 |
| Conar Ltd | Construction | 2024 |
| Concarn Limited | Real estate | 2005 |
| Conception Developments Limited | Construction | 2012 |
| Condor Campers Ltd | Administrative & support | 2021 |
| Congee Intl Limited | Wholesale & retail | 2022 |
| Connect 247 Ltd | Transport & logistics | 2019 |
| Connections That Matter Limited | Information & communication | 2026 |
| Connelly Group Limited | Financial services | 2026 |
| Connelly Property Development Limited | Real estate | 2024 |
| Connelly Property Paisley Limited | Real estate | 2026 |
| Conrad Scaffolding Services Limited | Construction | 2019 |
| Construct Scenery (Holdings) Limited | Construction | 2019 |
| Construct Scenery Limited | Construction | 2006 |
| Consulting Administration and Events Management Ltd | Hospitality | 2024 |
| Content Development Services Limited | Information & communication | 2014 |
| Contract Assistance + Recovery Management Ltd | Professional & scientific | 2014 |
| Contracted Trained Security Ltd | Administrative & support | 2009 |
| Cookie Champions Limited | Wholesale & retail | 2023 |
| Coombe Street Limited | Real estate | 2020 |
| Copal Asset Finance Ltd | Financial services | 2013 |
| Coproms Evoke Ltd | Administrative & support | 2024 |
| Copyprint Holdings Limited | Professional & scientific | 1981 |
| Core IT Consulting Ltd | Information & communication | 2025 |
| Corporate Print Boutique Limited | Manufacturing | 2016 |
| Correct Decor Limited | Construction | 2012 |
| Cosmoflo Property Ltd | Other services | 2018 |
| Courtfield Property Limited | Real estate | 2019 |
| Courtman Electrical Contractors Limited | Construction | 2026 |
| Cowburn Ltd | Real estate | 2023 |
| Cozyfox Ltd | Real estate | 2023 |
| CP Magnolia Limited | Construction | 2018 |
| CR Cleaning Solutions Ltd | Administrative & support | 2024 |
| Crafty Conversations Ltd | Arts & recreation | 2025 |
| Craig Construction (Southern) Limited | Arts & recreation | 1989 |
| Creaking Bones Productions Limited | Information & communication | 2017 |
| Creea Ltd | Professional & scientific | 2005 |
| Creowaves Ltd | Wholesale & retail | 2023 |
| Crescendo Studioz Ltd | Education | 2025 |
| Creswick Properties Limited | Real estate | 2019 |
| Croft Willow Limited | Real estate | 2017 |
| Croham Valley Management Company Ltd | Households | 2024 |
| Crosby Land and Estates Ltd | Real estate | 2016 |
| Cross Country Building Services Limited | Wholesale & retail | 2014 |
| Crossroads Theatre CIC | Health & social care | 2026 |
| Croydon ACR Ltd | Professional & scientific | 2024 |
| Croydon Automatics Limited | Wholesale & retail | 2012 |
| Croydon Business Hub Limited | Administrative & support | 2018 |
| Croydon Road (Management) Company Limited | Administrative & support | 1972 |
| Croydon Road Residents Association (Surrey) Limited | Administrative & support | 1993 |
| Croydon Training Hub | Administrative & support | 2023 |
| Crunch Fest Ltd | Hospitality | 2025 |
| Crystal Property Care Ltd | Real estate | 2024 |
| Cubic Index Limited | Professional & scientific | 2013 |
| Cubik Consulting Services Ltd | Professional & scientific | 2021 |
| Cubz Group Ltd | Health & social care | 2023 |
| Cullen's Clearances Ltd | Water & waste | 2012 |
| Cullens of Surrey Auctions Limited | Wholesale & retail | 2021 |
| Cunden Asset Management Ltd | Real estate | 2026 |
| Cuppa Chaii (Wallington) Ltd | Hospitality | 2024 |
| Curry House 2026 Limited | Hospitality | 2026 |
| Custom Carpentry & Construction Ltd | Construction | 2019 |
| Custom Furniture Limited | Manufacturing | 2018 |
| Customer Service IP Limited | Information & communication | 2001 |
| Cuvelle Ltd | Wholesale & retail | 2024 |
| CVR London Limited | Information & communication | 2016 |
| CXE Solutions Ltd | Health & social care | 2026 |
| Cybertector Ltd | Extraterritorial | 2025 |
| Cyberted Limited | Professional & scientific | 2016 |
| Cygnet IT Services CIC | Information & communication | 2015 |
| D & L UK Epsom Limited | Real estate | 2010 |
| D & S Hire Limited | Administrative & support | 2003 |