| Coda Autos Ltd | Wholesale & retail | 2023 |
| Coda Dance Company | Arts & recreation | 2013 |
| Code Spot Ltd | Wholesale & retail | 2020 |
| Codeklick Limited | Information & communication | 2025 |
| Codricel Ltd | Construction | 2016 |
| Codyaline'Shine Limited | Wholesale & retail | 2022 |
| Coffeelor Ltd | Hospitality | 2026 |
| Coja HQ Ltd | Wholesale & retail | 2025 |
| Cole Rail Ltd | Construction | 2022 |
| Cole Transport Ltd | Transport & logistics | 2025 |
| Collab Limited | Education | 2007 |
| College Close Management Company Limited | Households | 1989 |
| Colley Limited | Manufacturing | 2023 |
| Colmena Group Ltd | Administrative & support | 2021 |
| Colortec Enterprise Ltd | Wholesale & retail | 2013 |
| Colourful 2013 Limited | Wholesale & retail | 2015 |
| Columbia Wharf (B C D E & F) Management Company Limited | Administrative & support | 1996 |
| Comat Ltd | Transport & logistics | 2007 |
| Comfordable Homes & Ventures Limited | Real estate | 2023 |
| Comfordable Management Ltd | Real estate | 2026 |
| Comfort Ride Limited | Transport & logistics | 2017 |
| Comforters Care UK Limited | Health & social care | 2022 |
| Commercial Aspects (Management) Ltd. | Construction | 2018 |
| Commercial Contracts Ltd | Construction | 2023 |
| Commodore Kitchens Limited | Manufacturing | 1979 |
| Community College London Limited | Education | 2003 |
| Communomics CIC | Administrative & support | 2024 |
| Communovation Ltd | Information & communication | 2025 |
| Compact Edge Limited | Real estate | 2014 |
| Compass Advisory Ltd | Professional & scientific | 2024 |
| Compass Veterinary Clinic Ltd | Professional & scientific | 2026 |
| Compassion and Hope Ltd | Health & social care | 2015 |
| Compassionate Care Recruitment Ltd | Administrative & support | 2019 |
| Complete Cars Ltd | Wholesale & retail | 2024 |
| Complete Fixture & Fittings Limited | Wholesale & retail | 2022 |
| Completesearch Ltd | Information & communication | 2017 |
| Compound Asset Management Limited | Real estate | 2015 |
| Compound Partners Limited | Administrative & support | 2010 |
| Compression Advisory Limited | Other services | 2011 |
| Comstar Ltd | Information & communication | 2025 |
| Concord Sounds Limited | Administrative & support | 2023 |
| Conectuk Ltd | Wholesale & retail | 2025 |
| Connaught Shipping Agency Limited | Transport & logistics | 1961 |
| Connect and Construct CIC | Professional & scientific | 2026 |
| Connect Living Hub Limited | Health & social care | 2024 |
| Connect Part & Cars Sales Ltd | Wholesale & retail | 2025 |
| Connex Electrical & Building Services Ltd | Construction | 2011 |
| Connexis Global Ltd | Financial services | 2024 |
| Connie Construct Ltd | Construction | 2018 |
| Connie Investment Ltd | Real estate | 2024 |
| Conquest Data Limited | Information & communication | 2025 |
| Conrad Consulting Solutions Ltd | Professional & scientific | 2022 |
| Conscience Investments Ltd | Real estate | 2022 |
| Consolidated Insulation Services Limited | Construction | 1987 |
| Constantin Logistics Ltd | Transport & logistics | 2015 |
| Constantin-Robert Ltd | Transport & logistics | 2026 |
| Constructed Solutions Ltd | Professional & scientific | 2012 |
| Construction Base Ltd | Construction | 2022 |
| Construction Buildup UK Ltd | Construction | 2026 |
| Construction Mold Ltd | Construction | 2022 |
| Construction of Your Dreams Ltd | Construction | 2021 |
| Construction Properties Limited | Real estate | 2025 |
| Construction Rail Operators Ltd | Construction | 2014 |
| Consulting Planet UK Ltd | Professional & scientific | 2020 |
| Consumable City Limited | Wholesale & retail | 2008 |
| Contigo Commercial Finance Limited | Financial services | 2025 |
| Continuum Partners Limited | Information & communication | 2025 |
| Convil Limited | Construction | 2025 |
| Coocoodolove Ltd | Extraterritorial | 2016 |
| Cook EAT Repeat Ltd | Manufacturing | 2019 |
| Cooldelivery Ltd | Transport & logistics | 2020 |
| Coppid Hall (North Stifford) Limited | Real estate | 1985 |
| Coral Cleanco Ltd | Administrative & support | 2026 |
| Corbetis Ltd | Professional & scientific | 2025 |
| Core Media Services (UK) Ltd | Construction | 2008 |
| Corebuild Modular Ltd | Manufacturing | 2026 |
| Corene Clothing Ltd | Extraterritorial | 2024 |
| Cornerstone Wealth Capital Ltd | Professional & scientific | 2022 |
| Cornerstone Wealth Property Limited | Real estate | 2022 |
| Corporate Metrics Limited | Administrative & support | 1999 |
| Cosminuk Drive Ltd | Transport & logistics | 2017 |
| Cosmo Organics Ltd | Wholesale & retail | 2020 |
| Costas Serv Decorating Limited | Construction | 2018 |
| Costesti Limited | Construction | 2019 |
| Cosy Charm Ltd | Real estate | 2024 |
| Cosy Group Limited | Construction | 2024 |
| Cosyambient Ltd | Construction | 2017 |
| Cotoma Properties Ltd | Real estate | 2025 |
| Country Leisure Sales Ltd | Hospitality | 2025 |
| Courage Life Limited | Health & social care | 2022 |
| Courageous Conversations Limited | Administrative & support | 2020 |
| Coveney Property Limited | Households | 2021 |
| Covered Insurance Services Limited | Administrative & support | 2004 |
| CR Bland Baker Limited | Professional & scientific | 2021 |
| CR Contractors Ltd | Administrative & support | 2016 |
| Crade Limited | Wholesale & retail | 2024 |
| Craftastik Limited | Wholesale & retail | 2018 |
| Crammavill Ltd | Hospitality | 2025 |
| Crazy Cart Ltd | Wholesale & retail | 2025 |
| Crealytics UK Ltd | Information & communication | 2014 |