| Cornish Country Larder Limited | Manufacturing | 1996 |
| Cornish Coves Limited | Hospitality | 2021 |
| Cornmore Limited | Other services | 2023 |
| Coro Clean Energy Limited | Professional & scientific | 2018 |
| Coro Clean Energy Vietnam Limited | Professional & scientific | 2021 |
| Coro Energy Asia Limited | Professional & scientific | 2018 |
| Coro Energy Holdings Cell a Limited | Professional & scientific | 2019 |
| Coro Energy PLC | Energy | 2016 |
| Cororima Ltd | Extraterritorial | 2026 |
| Corpad Wealth Management Ltd | Financial services | 2018 |
| Corporate and Branded Cupcakes Ltd | Hospitality | 2023 |
| Corporate Communications (North East) Limited | Wholesale & retail | 2008 |
| Corporate Computer Supplies Limited | Information & communication | 2006 |
| Corporate Document Services Limited | Information & communication | 1994 |
| Corporate Growth Solutions Limited | Administrative & support | 2010 |
| Corporate Leadership Consulting Limited | Professional & scientific | 2019 |
| Corporate Office Furniture Limited | Manufacturing | 2013 |
| Corporate Pensions Administration Limited | Financial services | 2007 |
| Corporate Seed Capital Limited | Financial services | 1998 |
| Corporate Workspace Holdings Limited | Financial services | 2024 |
| Corporate Workspace Limited | Wholesale & retail | 2001 |
| Corporation Street Management Company Limited | Professional & scientific | 2001 |
| Corporations Cleaning Limited | Water & waste | 2016 |
| Corpx Ltd | Professional & scientific | 2024 |
| Corre Energy Ltd | Administrative & support | 2020 |
| Corrib Limited | Real estate | 2025 |
| Corrib Medical Limited | Health & social care | 2021 |
| CORRIDOR8 Ltd. | Arts & recreation | 2017 |
| Corrigan & Sons Construction Limited | Construction | 2014 |
| Corrocoat Services Limited | Extraterritorial | 2002 |
| Corrolabs Limited | Professional & scientific | 2020 |
| Corroserve Limited | Extraterritorial | 2015 |
| Corrosioneering Limited | Extraterritorial | 2002 |
| Corson Court Property Management Co Limited | Households | 2014 |
| Corten Management UK Limited | Financial services | 2018 |
| Cortex Ventures LLP | | 2016 |
| Corvus Air Cargo Limited | Transport & logistics | 1987 |
| Corvus Consulting Partners Ltd | Information & communication | 2025 |
| Corvus Holdings Limited | Financial services | 2017 |
| Corvyn Ltd | Wholesale & retail | 2026 |
| Cos-Phi Ltd | Construction | 2016 |
| Cosain Consulting Limited | Education | 2015 |
| Cosalt Lighting Limited | Extraterritorial | 1998 |
| Cosmetic Couture Education Ltd | Education | 2023 |
| Cosmetic Couture Limited | Health & social care | 2012 |
| Cosmetics and Scents Ltd | Wholesale & retail | 2023 |
| COSMETICS4BEAUTY Ltd | Wholesale & retail | 2019 |
| Cosmeticstar Ltd | Health & social care | 2024 |
| Cosmic (EVC) Asset Co 1 Ltd | Administrative & support | 2025 |
| Cosmic (EVC) Limited | Administrative & support | 2020 |
| Cosmic (EVC) Services Ltd | Administrative & support | 2025 |
| Cosmic Drifters Ltd | Manufacturing | 2021 |
| Cosmic Keyholding Security Services Limited | Professional & scientific | 1997 |
| Cosmic Leisure Limited | Arts & recreation | 2019 |
| Cosmo Baguette Ltd | Hospitality | 2026 |
| Cossy Homes Limited | Real estate | 2024 |
| Costel Gangal Ltd Limited | Transport & logistics | 2025 |
| Costel Marin Ltd | Transport & logistics | 2023 |
| Costello & Abrey Ltd | Hospitality | 2023 |
| Costep Ltd | Wholesale & retail | 2023 |
| Costigan Psychotherapy Solutions Ltd | Health & social care | 2022 |
| Costock Building Services Limited | Construction | 2012 |
| Cosy Cave Properties Ltd | Real estate | 2024 |
| Cosy Home Services Ltd | Construction | 2023 |
| Cosy Prop's Limited | Real estate | 2020 |
| Cosy Stays Away Ltd | Hospitality | 2022 |
| Cosyhome Building Services Ltd | Construction | 2019 |
| Cosytoes Heating Products Ltd. | Manufacturing | 2000 |
| Cosyum Ltd | Real estate | 2024 |
| Coterie Marketing Limited | Professional & scientific | 2013 |
| Cottage Stores Limited | Wholesale & retail | 2003 |
| Cotterwell Limited | Real estate | 2000 |
| Cottingley Barbers Ltd | Other services | 2026 |
| Cottingley Collective CIC | Other services | 2026 |
| Cotton Mill (Burnley) Management Company Limited | Households | 2004 |
| Cotton Toft Educational Limited | Education | 2015 |
| Cottontrend UK Limited | Wholesale & retail | 2020 |
| Cougar Signs Ltd | Professional & scientific | 2010 |
| Cougarmania Ltd | Arts & recreation | 2018 |
| Coulisse UK Ltd | Wholesale & retail | 2019 |
| Coulton House Properties Limited | Real estate | 2024 |
| COUNSEL2COUNCILS Limited | Professional & scientific | 2011 |
| Count on Us-Children and Adults in Crisis Programs Ltd | Administrative & support | 2019 |
| Counterpoint Technologies Ltd | Information & communication | 2023 |
| Country and Cobbles Limited | Wholesale & retail | 2024 |
| Country and Wolds Ltd | Hospitality | 2025 |
| Country Bear Holdings Limited | Hospitality | 2024 |
| Country Blinds & Awnings Ltd | Other services | 2008 |
| Country Pubs 1 Ltd | Hospitality | 2018 |
| Country Style Foods (Europe) Limited | Manufacturing | 2010 |
| Country Style Ventures Limited | Extraterritorial | 2021 |
| Countrylarge (Canal Mills) Limited | Construction | 2014 |
| Countrylarge (Globe Works) Limited | Professional & scientific | 2017 |
| Countrylarge (Kirkstall Road) Ltd | Real estate | 2018 |
| Countrylarge (Sayner Lane) Limited | Construction | 2018 |
| Countrylarge (Wrays) Ltd | Real estate | 2020 |
| Countrylarge 444 Limited | Real estate | 2018 |
| Countrylarge Aire Place Mills Limited | Construction | 2025 |
| Countrylarge CC Limited | Real estate | 2022 |
| Countrylarge Developments Limited | Construction | 2025 |