| Coe's Bespoke Jewellers Limited | Manufacturing | 2019 |
| Coelevate Ltd | Administrative & support | 2025 |
| Coemgenus Ltd | Information & communication | 2025 |
| COFF33 Ltd | Hospitality | 2022 |
| Coffee Marylebone Ltd | Hospitality | 2021 |
| Cognatix Ltd | Professional & scientific | 2025 |
| Coldroom Direct Limited | Other services | 2017 |
| Coleman Fields Limited | Real estate | 2019 |
| Coleman UK Group Limited | Energy | 2017 |
| Coles Colloquial Limited | Professional & scientific | 2022 |
| Colin Branson (Flooring) Limited | Construction | 2001 |
| Colin Harvey Limited | Professional & scientific | 2015 |
| Collins Cartons (Essex) Limited | Water & waste | 2003 |
| Collins Packaging Supplies Ltd | Administrative & support | 2011 |
| Color Splash Ltd | Construction | 2024 |
| Colton Commercials Haulage Limited | Other services | 1994 |
| Colton Transport Limited | Administrative & support | 2004 |
| Colwood Motors (UK) Limited | Wholesale & retail | 2014 |
| Comario Ltd | Construction | 2016 |
| Come Chaat With ME Ltd | Wholesale & retail | 2025 |
| Comida Contracts Limited | Extraterritorial | 2025 |
| Command Z Ltd | Manufacturing | 2018 |
| Commulite EVO Ltd | Manufacturing | 2024 |
| Commulite Limited | Manufacturing | 2009 |
| Community College Initiative Ltd | Education | 2015 |
| Community Gaming Limited | Information & communication | 2021 |
| Compass Rose Investments Limited | Financial services | 2014 |
| Complete Acoustics Limited | Other services | 2020 |
| Complete Boiler Solutions Ltd | Construction | 2021 |
| Complete Contract Services (CCS) Ltd | Construction | 2016 |
| Complete Property Consultants Ltd | Real estate | 2023 |
| Complete Refurbishment Services Ltd | Construction | 2013 |
| Completion Homes Ltd | Construction | 2017 |
| Compliance 4 Buildings Limited | Other services | 2019 |
| Compounding LAB Ltd | Manufacturing | 2023 |
| Computer Wizard Limited | Wholesale & retail | 2004 |
| Computrans Technology Limited | Information & communication | 2006 |
| Concell Scaffolding Limited | Construction | 2021 |
| Concept 55 Limited | Professional & scientific | 2010 |
| Concept Communications International Limited | Professional & scientific | 2016 |
| Concept Home Improvements Ltd | Construction | 2002 |
| Concept Supplies Limited | Construction | 2015 |
| Concept Windows Group Limited | Real estate | 1993 |
| Concord Cctv Ltd | Administrative & support | 2022 |
| Concord Partners Limited | Administrative & support | 2021 |
| Condition Collective Ltd | Education | 2024 |
| Condor Capital Ltd | Construction | 2018 |
| Confidence Care Service UK Ltd | Health & social care | 2018 |
| Connect Experts Ltd | Financial services | 2026 |
| Connect Finance Group Ltd | Administrative & support | 2009 |
| Connect IFA Ltd | Financial services | 2005 |
| Connectory Limited | Wholesale & retail | 2023 |
| Connexum Trading Ltd | Wholesale & retail | 2024 |
| Console Clinic Limited | Information & communication | 2013 |
| Console Clinic Sales Limited | Other services | 2024 |
| Consoma Support Services Limited | Health & social care | 2022 |
| Construction Trade Skills Training Limited | Construction | 2012 |
| Construction-Consultants Hub Limited | Construction | 2020 |
| Constructionsiteai Ltd | Other services | 2025 |
| Constructionsiteaik Ltd | Other services | 2025 |
| Constructive Concepts Ltd | Construction | 2024 |
| Constructpro Consultancy Limited | Construction | 2024 |
| Consultiq Ltd | Information & communication | 2024 |
| Contec Consulting Limited | Professional & scientific | 2016 |
| Contemporary Sales Ltd | Professional & scientific | 2022 |
| Content for Brides Ltd | Information & communication | 2023 |
| Continental Business Enterprise Limited | Construction | 2010 |
| Continental Interior Services Ltd | Construction | 2021 |
| Continuum Ventures Limited | Professional & scientific | 2015 |
| Convertkraft Media Ltd | Wholesale & retail | 2026 |
| Convurt Ltd | Construction | 2016 |
| Cool Masters Ltd. | Manufacturing | 2013 |
| Copia Bespoke Limited | Administrative & support | 2013 |
| Coral Aesthetics Ltd | Wholesale & retail | 2022 |
| Coral Reef Estates Limited | Real estate | 2020 |
| Coral Reef Lettings and Management Limited | Real estate | 2016 |
| Coral Reef Properties Limited | Construction | 2018 |
| Corbett & Shakir Ltd | Other services | 2023 |
| Corhaven Developments Ltd | Financial services | 2022 |
| Corinthian C Limited | Construction | 2022 |
| Cork and Feathers Ltd | Extraterritorial | 2023 |
| Corkscrew Enterprises Limited | Information & communication | 1995 |
| Cornerstone Dwellings Ltd | Real estate | 2025 |
| Cornerstone Legacy Limited | Health & social care | 2020 |
| Corovika Property Holdings Ltd | Real estate | 2024 |
| Cortex A1 Limited | Financial services | 2018 |
| Cory Transport Ltd | Transport & logistics | 2026 |
| Cosma Fragrances Limited | Wholesale & retail | 2017 |
| Cosmoco Limited | Arts & recreation | 2013 |
| Costans Ltd | Information & communication | 2012 |
| Cotswolds Holiday Cottage Limited | Real estate | 2023 |
| Cotter Technical Services Limited | Manufacturing | 2016 |
| Counterpoint Solutions Limited | Professional & scientific | 2018 |
| Countrywide Accident Claims Ltd | Other services | 2011 |
| Countrywide South East LLP | | 2012 |
| Cousins Roofing Contractors Limited | Construction | 2021 |
| COY Lands Ltd | Construction | 2021 |
| CP Living Ltd | Health & social care | 2024 |
| CPG Properties Ltd | Real estate | 2024 |
| CPM Property Maintenance Ltd | Construction | 2016 |