| Colin Barnes Signs Limited | Other services | 2004 |
| College Road Clifton Management Limited | Households | 2024 |
| Combi Response Limited | Construction | 2014 |
| Comfii Casa Ltd | Real estate | 2024 |
| Comm Sense Limited | Wholesale & retail | 1999 |
| Commercial Finance London Limited | Professional & scientific | 2018 |
| Commercial Flooring Solutions Limited | Construction | 2026 |
| Comms After Dark Ltd | Professional & scientific | 2025 |
| Communichild CIC | Other services | 2023 |
| Concept 360 Ltd | Professional & scientific | 2023 |
| Concept Groundworks Ltd | Construction | 2025 |
| Concept to Build Ltd | Construction | 2022 |
| Conder Rent Ltd | Real estate | 2025 |
| Coniston Court (Epping) Flat Management Limited | Households | 1977 |
| Coniston Court (Epping) Freehold Limited | Households | 1997 |
| Connorthompson Limited | Manufacturing | 2019 |
| Consolidare Limited | Wholesale & retail | 2025 |
| Construction Wise Minds CIC | Health & social care | 2018 |
| Continental Scaffolding Ltd | Construction | 2014 |
| Convexa Creativo Limited | Professional & scientific | 2026 |
| Cool-Air SDN Ltd | Construction | 2024 |
| Coppi Limited | Administrative & support | 2009 |
| Corellia Limited | Administrative & support | 2022 |
| Cornerstone Property Preholding LLP | | 2016 |
| Corsham Kebab House Limited | Hospitality | 2019 |
| Coskun Kebab Pizza Ltd | Hospitality | 2024 |
| Cosmage Ltd | Wholesale & retail | 2019 |
| Cosmos Omega Ltd | Professional & scientific | 2019 |
| Couper Earnshaw Limited | Construction | 2009 |
| Court House Properties (Barnet) Limited | Real estate | 2016 |
| Cousin's Waste OIL Limited | Water & waste | 2025 |
| Cover Asia Press Limited | Information & communication | 2013 |
| CPIL1 Limited | Real estate | 2023 |
| CPM Industries Limited | Wholesale & retail | 2019 |
| CR Clearance & Removals Limited | Transport & logistics | 2007 |
| Cranbrook Estate Management Company Limited | Households | 2022 |
| Creadias Limited | Professional & scientific | 2022 |
| Creative Scapes Gardening Ltd | Administrative & support | 2018 |
| Creative Scapes London Ltd | Administrative & support | 2016 |
| Crepe and Shake Ltd | Hospitality | 2023 |
| Crescendum Holdings Limited | Professional & scientific | 2019 |
| Crew Studio Ltd | Professional & scientific | 2013 |
| Cribben and SON Ltd | Construction | 2016 |
| Cristi Utility Ltd | Construction | 2020 |
| Cross Market International Ltd | Wholesale & retail | 2025 |
| Crossfit Hertford Limited | Arts & recreation | 2011 |
| Crowd House Properties Ltd | Real estate | 2020 |
| Crowe IMT Ltd | Wholesale & retail | 2025 |
| Crown Candy UK Ltd | Wholesale & retail | 2025 |
| Crown Close (Leasehold) Manco Limited | Households | 2017 |
| Crown Close Manco Ltd | Households | 2017 |
| Crown Flame Services Ltd | Construction | 2026 |
| Crystal Cole Group Ltd | Manufacturing | 2017 |
| Crystal Lines Limited | Transport & logistics | 2003 |
| Crystallise Services Ltd | Administrative & support | 2023 |
| CSB Financial Services Limited | Financial services | 2015 |
| CSW Exterior Maintenance Ltd | Administrative & support | 2024 |
| Cubi Construction Ltd | Construction | 2017 |
| Cumo London Limited | Wholesale & retail | 2018 |
| Cunningham Holdings (London) Limited | Construction | 2012 |
| Curated by Butta Ltd | Other services | 2024 |
| Curie Consulting Ltd | Professional & scientific | 2022 |
| Curtis Cladding & Roofline Ltd | Construction | 2026 |
| Cutting Edge Combat Limited | Arts & recreation | 2014 |
| CVF Estates Ltd | Real estate | 2022 |
| CWA Accountants Limited | Professional & scientific | 2015 |
| CWA Group Limited | Real estate | 2023 |
| CWA Partners Ltd | Professional & scientific | 2017 |
| CWA Taxation Limited | Professional & scientific | 2025 |
| Cwtch Coffee House Ltd | Hospitality | 2022 |
| CYB3R Ltd | Administrative & support | 2018 |
| CYB3R Solutions Ltd | Administrative & support | 2014 |
| Cyprus Construction & Maintenance Ltd | Construction | 2025 |
| Cyprus Horizons Limited | Hospitality | 2025 |
| D & M Mechanical Bodyshop Limited | Wholesale & retail | 2022 |
| D D Deli Limited | Information & communication | 2017 |
| D&Bros Ltd | Construction | 2018 |
| D.G. Thompson Limited | Wholesale & retail | 2001 |
| Dacorum Investment Partnership LLP | | 2025 |
| Dagenham (UK) Brothers Cafe Ltd | Hospitality | 2016 |
| Dagenham Green Hill P1 LLP | | 2023 |
| Daily Cakes Limited | Wholesale & retail | 2016 |
| Daista Ltd | Construction | 2008 |
| Dambrook Limited | Construction | 2011 |
| Damned Good Scaffolding Limited | Construction | 2018 |
| Dampmaster Enfield Limited | Professional & scientific | 2025 |
| DAN Macdonald Editing Limited | Information & communication | 2014 |
| Danachris Trans Ltd | Transport & logistics | 2019 |
| Danail Vakarelski Shop Fitting Ltd | Construction | 2015 |
| Dancescape Limited | Arts & recreation | 2014 |
| Daniel James Chauffeurs Ltd | Transport & logistics | 2018 |
| Daniel Lewis & SON Limited | Wholesale & retail | 1945 |
| Daniel Lock Ltd | Professional & scientific | 2011 |
| Daniel Transport & Recovery Ltd | Transport & logistics | 2018 |
| Danilo Calendars Limited | Manufacturing | 1990 |
| Danilo Limited | Professional & scientific | 1996 |
| Danilo Printing Limited | Manufacturing | 1976 |
| Danilo Promotions Limited | Manufacturing | 1978 |
| Dante VAS Ltd | Transport & logistics | 2023 |
| Daphine Ltd | Construction | 2025 |