| Cherry BLU Limited | Wholesale & retail | 2008 |
| Cheval Manor Management Limited | Households | 2022 |
| Chevron Alarms Holdings Limited | Financial services | 2019 |
| Chevron Alarms Ltd | Administrative & support | 2007 |
| Chg-Meridian (Holdings) UK Limited | Financial services | 2000 |
| Chg-Meridian UK Limited | Financial services | 1976 |
| Chichester Care Home Holdings Limited | Financial services | 2019 |
| Chichester Care Home Limited | Health & social care | 2018 |
| Chichester Care Limited | Health & social care | 2018 |
| Chivers Cladding Limited | Construction | 1989 |
| Chris FAY Ltd | Professional & scientific | 2026 |
| Church Court Residents Company Limited | Real estate | 1981 |
| Church Road Mews Management Limited | Real estate | 2022 |
| Churchill Contract Solutions Ltd | Construction | 2025 |
| Churchill Park (Hounslow) Management Company Limited | Households | 1997 |
| Churston Close Limited | Real estate | 1998 |
| Ciconia Group Holding Ltd | Financial services | 2023 |
| Ciconia Projects Ltd | Construction | 2023 |
| Ciconia Properties Limited | Real estate | 2018 |
| Ciconia Trading Ltd | Hospitality | 2018 |
| Cinarali Ltd | Other services | 2022 |
| Cinnamon (S1) Limited | Real estate | 2019 |
| Cinnamon (S2) Limited | Real estate | 2019 |
| Cinnamon Land Limited | Real estate | 2015 |
| Cinnamon Retirement Living (Inveresk) Limited | Health & social care | 2018 |
| CJ Audio Visual Limited | Information & communication | 2024 |
| CJC IS Limited | Professional & scientific | 1997 |
| CJF Property Developments Limited | Construction | 2025 |
| Clackers Carpentry Ltd | Manufacturing | 2021 |
| Claessen Rental Investments Limited | Real estate | 2023 |
| Claire Bealing Consulting Limited | Administrative & support | 2018 |
| Clarence Court Residents Company Limited | Households | 1988 |
| Classic Kitchen Worktops Ltd | Manufacturing | 2025 |
| Cleaning Solutions Services Ltd | Extraterritorial | 2018 |
| Clear-A-Space Limited | Transport & logistics | 2005 |
| Clearsky Environmental Relief Ltd | Other services | 2024 |
| Cleator Moor Development Ltd | Real estate | 2023 |
| Cleveland House Development Ltd | Construction | 2024 |
| Clever Platforms Ltd | Administrative & support | 2016 |
| Clich Ltd | Real estate | 2021 |
| Clicked Ltd | Professional & scientific | 2013 |
| Clima Vision Ltd | Professional & scientific | 2024 |
| Climapartner Ltd | Professional & scientific | 2024 |
| Climbforce Limited | Real estate | 2013 |
| Cloudkore Ltd | Information & communication | 2023 |
| CM Expert Consultancy Ltd | Administrative & support | 2024 |
| CMP Digital Services Ltd | Information & communication | 2023 |
| CNC Property Fund Management Limited | Real estate | 1904 |
| CNC Property Management Services Limited | Professional & scientific | 2007 |
| Co SEC Number 4 Limited | Professional & scientific | 2011 |
| CO2 Certificates Ltd | Professional & scientific | 2024 |
| Coactus Growth Solutions Limited | Extraterritorial | 2014 |
| Cobham Care Home Holdings Limited | Financial services | 2019 |
| Cobham Care Home Limited | Health & social care | 2016 |
| Cobham Care Services Limited | Health & social care | 2019 |
| Cobolt Software Limited | Information & communication | 2023 |
| Cobra Collective CIC | Professional & scientific | 2016 |
| Coco Bahia Limited | Professional & scientific | 2008 |
| Cognitive Behavioural Therapist Ltd | Other services | 2010 |
| Colbuild Properties Ltd | Real estate | 2021 |
| Colgain Trading Ltd | Real estate | 2021 |
| Colnbrook Homes Ltd | Financial services | 2022 |
| Comfybrix Limited | Hospitality | 2021 |
| Commercial Showfer Limited | Transport & logistics | 2013 |
| Commotive Property Ltd | Real estate | 2017 |
| Commotive Trading Ltd | Real estate | 2017 |
| Compass House Investment Ltd. | Real estate | 2022 |
| Compass Learning Ltd | Education | 2009 |
| Compassion for Earth & Education Ltd | Other services | 2024 |
| Compassionis Ltd | Other services | 2025 |
| Compliance Web Ltd | Education | 2021 |
| Computecare Ltd | Information & communication | 2019 |
| Computer Contracts Limited | Administrative & support | 2005 |
| Computer Creations Ltd | Education | 2019 |
| Computer Financial Consultants Limited | Information & communication | 1993 |
| Computerzoom Ltd | Wholesale & retail | 2022 |
| Concept Media Solutions Ltd | Professional & scientific | 2025 |
| Concrete Oval Limited | Professional & scientific | 2001 |
| Conduct Culture Ltd | Professional & scientific | 2019 |
| Connaught Park Construction Ltd | Construction | 2024 |
| Contact Detailing Ltd | Administrative & support | 2025 |
| Cooper Education Ltd | Other services | 2025 |
| Core Ability Merch Ltd | Wholesale & retail | 2025 |
| Core Vision Solutions Limited | Construction | 2024 |
| Corner Capital Limited | Real estate | 2025 |
| Corniche Hotels Limited | Financial services | 1995 |
| Cornucopia Global Ltd | Wholesale & retail | 2023 |
| Corpra Capital Limited | Hospitality | 2024 |
| Cosa Nostra Films Ltd | Information & communication | 2021 |
| Cosmic Cloud Limited | Information & communication | 2022 |
| Cossette Holdings Limited | Financial services | 2024 |
| Cotonic Ltd | Wholesale & retail | 2023 |
| Courtel Communications Limited | Information & communication | 1999 |
| Courtshore Limited | Real estate | 2013 |
| Cowley Groceries Ltd | Wholesale & retail | 2026 |
| CP Familienstiftung Ltd | Professional & scientific | 2023 |
| CRA Roofing Specialist Ltd | Construction | 2021 |
| Crabtree Commercial Repairs Limited | Wholesale & retail | 2012 |
| Crabtree Security Services Ltd | Extraterritorial | 2014 |
| CRD Services Limited | Construction | 2022 |