| CARE4YOURHAIR Limited | Other services | 2015 |
| Carleschi Ltd | Manufacturing | 2023 |
| Casas Capital Co Ltd | Real estate | 2025 |
| Casas Professional Services Ltd | Professional & scientific | 2015 |
| Cascades Consultants Ltd | Administrative & support | 2024 |
| Catherine Price Art Limited | Arts & recreation | 2026 |
| Catiand International Ltd | Real estate | 2015 |
| Catoiqier Limited | Real estate | 2022 |
| CBA Lite Ltd | Construction | 2025 |
| Celtic Hotel Limited(The) | Hospitality | 1981 |
| Ceren Properties Limited | Real estate | 2017 |
| Cetin Cleaning Ltd | Administrative & support | 2019 |
| Cetus Quantitative Ltd | Information & communication | 2021 |
| CFO Services London Ltd | Professional & scientific | 2026 |
| Cgso Ltd | Construction | 2025 |
| CH Sports Media Ltd | Information & communication | 2021 |
| Chainflow Systems Ltd | Information & communication | 2026 |
| Chamberlaine Cleaning Services Limited | Other services | 1998 |
| Character Windows & Doors (2005) Limited | Construction | 2005 |
| Charles Amare Building Ltd | Construction | 2023 |
| Charlie Prints Ltd | Manufacturing | 2012 |
| Checkinuk Ltd | Professional & scientific | 2016 |
| Chelmsford Scaffolding Limited | Construction | 2013 |
| Cherry Tree Centre (Henley) Ltd | Real estate | 2020 |
| Cherry Tree Group Ltd | Real estate | 2023 |
| Cherry Tree Therapy Centre Ltd | Health & social care | 2018 |
| Chesterfield Venture Investments Limited | Professional & scientific | 2008 |
| Chestnuts Woodbyth Ltd | Hospitality | 2024 |
| Cheviot House Properties Limited | Real estate | 2003 |
| Chiforescu M Transport Ltd | Transport & logistics | 2025 |
| Chingford Industrial Management Limited | Real estate | 1984 |
| Chkh Ltd | Education | 2025 |
| Choir Creations Ltd | Arts & recreation | 2026 |
| Choo Limited | Information & communication | 2004 |
| Christeoir Limited | Transport & logistics | 2007 |
| Christian Farriers Ltd | Agriculture & fishing | 2025 |
| Chutnaze Limited | Manufacturing | 2025 |
| Circles Five LLP | | 2008 |
| Circles Five Property Development LLP | | 2016 |
| City PM London Ltd | Construction | 2011 |
| CKM Properties (Hull) Limited | Real estate | 2025 |
| Clairan Limited | Real estate | 2013 |
| Claire Investments Limited | Construction | 2009 |
| Claireart Ltd | Arts & recreation | 2019 |
| Clarehouse Developments Limited | Real estate | 2011 |
| Clarehouse Storage & Security Limited | Other services | 2021 |
| Clayton and Clayton Roofing & Building Limited | Construction | 2008 |
| Clickbean Ltd | Professional & scientific | 2018 |
| Cloverton Property Ltd | Real estate | 2003 |
| Club KO Ltd | Other services | 2015 |
| CM Consultants and Wellbeing Ltd | Health & social care | 2025 |
| CMP Business Ltd | Manufacturing | 2024 |
| Cmue Ltd | Professional & scientific | 2019 |
| CNL Consulting Ltd | Financial services | 2021 |
| Coco Colour and Extensions Specialists Ltd | Other services | 2011 |
| Code Zero Data Ltd | Information & communication | 2023 |
| Cohstudio Ltd | Information & communication | 2024 |
| Coltan Investments and Management Ltd | Real estate | 2023 |
| Comaal Limited | Construction | 2023 |
| Compass Property Holdings Ltd | Real estate | 2018 |
| Compliance Remedies Limited | Professional & scientific | 2006 |
| Concept Build (London) Limited | Construction | 2017 |
| Concept Group (London) Limited | Real estate | 2018 |
| Concept Property Holdings Limited | Real estate | 2018 |
| Connor J Tomlinson Media Limited | Professional & scientific | 2024 |
| Connor Stevens PHD Ltd | Construction | 2020 |
| Construction Pricebuilder Ltd | Construction | 2019 |
| CONSTRUCTION4ALL Ltd | Construction | 2024 |
| Consultant Microbiologist Ltd | Health & social care | 2021 |
| Contact Commercial Interiors Limited | Construction | 1997 |
| Cooling Control Properties Limited | Real estate | 2004 |
| Cooling Control Systems Ltd | Construction | 1995 |
| Coopers Renovations Limited | Construction | 2021 |
| Copperleigh Ventures (2025) Ltd | Other services | 2025 |
| Copycat Coffee Ltd | Hospitality | 2026 |
| Core Health and Fitness Limited | Arts & recreation | 2002 |
| Cortida Limited | Information & communication | 2019 |
| Cortida Sales Limited | Administrative & support | 2020 |
| Cory & JON Ltd | Health & social care | 2025 |
| Cosma Plumbing Limited | Construction | 2018 |
| Cost Transformation Consultancy Ltd | Professional & scientific | 2017 |
| Cousins Roofing Limited | Construction | 2003 |
| Coverion Ltd | Financial services | 2025 |
| CP Repair Centre Ltd | Other services | 2022 |
| Cphoenix Nail Bar Ltd | Other services | 2026 |
| CPM Agency Limited | Wholesale & retail | 2022 |
| Crackers HS Limited | Professional & scientific | 2026 |
| Craig Dyson Fitness Ltd | Arts & recreation | 2023 |
| Cranbrook Properties Ilford Limited | Real estate | 2015 |
| Crazy Removals Ltd | Transport & logistics | 2017 |
| CRE Capital Limited | Financial services | 2026 |
| Create Time Ltd | Other services | 2019 |
| Creating Syzygies Limited | Professional & scientific | 2018 |
| Creative E-Motion Ltd | Information & communication | 2015 |
| Creel & Co Limited | Administrative & support | 2009 |
| Crestline Recruitment Ltd | Administrative & support | 2025 |
| Cricket View Limited | Real estate | 1982 |
| Crimson Management Services Limited | Administrative & support | 2016 |
| Crimson River Productions Limited | Information & communication | 2011 |
| Cross Consulting Services Limited | Professional & scientific | 2015 |