| Candy Cloud Delights Ltd | Wholesale & retail | 2025 |
| Canopy Consult Ltd | Professional & scientific | 1999 |
| Canopy Ministries International Ltd | Education | 2012 |
| Canterbury Court Owners Limited | Households | 2013 |
| Canterbury Court RTM Company Ltd | Households | 2010 |
| Capebrook Limited | Households | 1971 |
| Capit Limited | Construction | 2010 |
| Carbeech Finance Limited | Professional & scientific | 2023 |
| Carbon Accounting Alliance Ltd | Other services | 2025 |
| Carbon Care Solutions Limited | Wholesale & retail | 2014 |
| Cardology Ltd | Wholesale & retail | 2014 |
| Care Stories Ltd | Information & communication | 2025 |
| Carew-Jones & Motley Limited | Wholesale & retail | 1977 |
| Caring for Orphans and the Needy CIC | Education | 2024 |
| Carmena Day Nursery (Thrale Road) Limited | Health & social care | 2004 |
| Carpal Tunnel Services Ltd | Health & social care | 2016 |
| Carshalton Lavender Community Interest Company | Agriculture & fishing | 2009 |
| Casa Caffe Limited | Hospitality | 2007 |
| Casado Hart Ltd | Information & communication | 2020 |
| Casalume Ltd | Real estate | 2026 |
| Castrell Properties Ltd | Real estate | 2026 |
| Caterham Construction Limited | Construction | 2022 |
| Caterina Catering Ltd | Hospitality | 2023 |
| CC (D2C) Limited | Manufacturing | 2025 |
| CCH Witney Limited | Real estate | 2021 |
| Ccre Limited | Construction | 2015 |
| CDS Signs Limited | Administrative & support | 2010 |
| Cedar Capital (C&C) Ltd | Professional & scientific | 2024 |
| Celercom Limited | Professional & scientific | 1998 |
| Cellcove Limited | Professional & scientific | 2008 |
| Celltec Engineering Ltd | Administrative & support | 2022 |
| Centaur Wellness & Health Ltd | Wholesale & retail | 2023 |
| Central IVF Limited | Health & social care | 2016 |
| Central Powerflush Ltd | Construction | 2023 |
| Centskill Limited | Wholesale & retail | 1988 |
| Cerriga Limited | Wholesale & retail | 2025 |
| CF (Wimbledon) Ltd | Arts & recreation | 2019 |
| CG Care Limited | Health & social care | 2025 |
| CG London Builders Ltd | Construction | 2022 |
| Cgtl Consultancy Limited | Professional & scientific | 2023 |
| Chaatpatters Ltd | Hospitality | 2025 |
| Chandru Technologies Ltd | Information & communication | 2026 |
| Chaps Barbers Redhill Limited | Other services | 2025 |
| Charge Films Ltd | Information & communication | 2024 |
| Chass Care Limited | Health & social care | 2022 |
| Chatterbox Childminding Ltd | Education | 2013 |
| Chattha Brothers Ltd | Construction | 2020 |
| Cheapcheapwasteremovalandgroundmaintenance Ltd | Water & waste | 2026 |
| Chelsea Electrical Limited | Construction | 2014 |
| Chessington Gates & Metalworks Limited | Manufacturing | 2025 |
| Chestnut Landing Ltd | Professional & scientific | 2023 |
| Chez Shivani Ltd | Information & communication | 2025 |
| CHI KI Holdings PTY Ltd | Education | 2024 |
| CHI NG Export Ltd | Wholesale & retail | 2025 |
| Chippy Lane Productions Ltd | Arts & recreation | 2017 |
| Chipstead Clubhouse Limited | Arts & recreation | 2018 |
| Chisei Analytics Ltd | Information & communication | 2015 |
| Choice Healthcare & Wellbeing Services Limited | Health & social care | 2023 |
| Christ's House Agency | Other services | 2020 |
| Christopher Banks Limited | Information & communication | 2008 |
| Chun HOU Limited | Hospitality | 2019 |
| Cibersoft Solutions Limited | Information & communication | 2014 |
| Cinnamon Swirl Fitness Ltd | Arts & recreation | 2020 |
| Circular Green Ltd | Administrative & support | 2024 |
| Cirrus Primary Academy Trust | Education | 2015 |
| City Property Management London Ltd | Real estate | 2020 |
| City Square Limited | Construction | 2012 |
| City Vector Ltd | Administrative & support | 2022 |
| CJB Electrical London Ltd | Construction | 2019 |
| CKM Vexousia Limited | Financial services | 2024 |
| Ckore Limited | Real estate | 2021 |
| Claimgenie Ltd | Administrative & support | 2026 |
| Clare Court Leaseholders Association Limited | Households | 1991 |
| Claremont House Management Company Limited | Households | 1989 |
| Clarence Brasserie Ltd | Information & communication | 2025 |
| Clarence Country Homes Limited | Real estate | 2004 |
| Clarke Care Services Limited | Health & social care | 2021 |
| Clarysam Cleaning Multiservices Limited | Administrative & support | 2023 |
| Clay Prop Co Ltd | Real estate | 2025 |
| Claygate Lake Ltd | Agriculture & fishing | 2019 |
| Clean Entry Locksmith Ltd | Manufacturing | 2026 |
| Clean Sweep Solutions Limited | Professional & scientific | 2023 |
| Cleaning Fairies London Limited | Administrative & support | 2022 |
| Clear IT OUT Ltd | Water & waste | 2016 |
| Clear Sky Electrical Ltd | Construction | 2011 |
| Clearcount Consulting Limited | Professional & scientific | 2022 |
| Clearsky Cloud Ltd | Other services | 2020 |
| Clearvue Home Improvements Limited | Construction | 2013 |
| Clearwaysten Limited | Information & communication | 2017 |
| Clemens Holdings Limited | Financial services | 2018 |
| Clemens Investments Limited | Real estate | 2025 |
| CLICK2CTRL Ltd | Information & communication | 2023 |
| Clifton Estates (Pubs) Ltd | Other services | 2014 |
| Cliphair Limited | Wholesale & retail | 2007 |
| Clocktower Cafe Limited | Hospitality | 2004 |
| Cloud 10 Productions Ltd | Information & communication | 2016 |
| Cloud Lane Ltd | Information & communication | 2020 |
| Cloudnix Limited | Information & communication | 2020 |
| Cloudsoft Technologies Ltd | Information & communication | 2019 |
| Cloudsyzen Security Ltd | Information & communication | 2025 |