| Cool Assets Ltd | Administrative & support | 2009 |
| Cool Initiatives Limited | Financial services | 2017 |
| Cool Milk Administration Limited | Administrative & support | 2010 |
| Cool Milk at School Limited | Administrative & support | 1998 |
| Cool Milk Cambria Limited | Administrative & support | 2003 |
| Cool Milk Group Limited | Financial services | 2004 |
| Cool Milk Limited | Administrative & support | 1998 |
| Cool Milk Sales and Marketing Ltd | Administrative & support | 2011 |
| Cool Refrigeration Limited | Other services | 1999 |
| Coolmain Services Limited | Wholesale & retail | 1986 |
| Cooper & Kime (Cleveland) Limited | Health & social care | 1995 |
| Cooperbox Ltd | Information & communication | 2025 |
| Coopers Healthcare Group Limited | Wholesale & retail | 2024 |
| Coppertail Limited | Wholesale & retail | 2020 |
| Coral Safety Ltd | Construction | 2022 |
| Core Build Ltd | Financial services | 2022 |
| Core Legal Limited | Professional & scientific | 2015 |
| Core Private Equity Ltd | Financial services | 2023 |
| Core Properties Newcastle Limited | Real estate | 2021 |
| Core Properties Teesside Limited | Real estate | 2018 |
| Core Properties Wakefield Limited | Households | 2018 |
| Core Properties York Limited | Real estate | 2021 |
| Core Psychology (Derby) Limited | Health & social care | 2014 |
| Core Psychology (Norwich) Limited | Health & social care | 2015 |
| Core Reformer Pilates Sedgefield Ltd | Arts & recreation | 2025 |
| Core Transition Limited | Professional & scientific | 2007 |
| Coreway Groundworks and Landscaping Limited | Construction | 2025 |
| Corner Shawarma Ltd | Hospitality | 2024 |
| Cornerdeals Ltd | Wholesale & retail | 2026 |
| Cornerstone Business Solutions Limited | Information & communication | 2008 |
| Cornerstone Commercial Property Solutions Limited | Real estate | 2022 |
| Cornerstone Holidays Ltd | Hospitality | 2025 |
| Cornerstone Marketing Solutions Ltd | Professional & scientific | 2019 |
| Cornerstone Stays Ltd | Real estate | 2026 |
| Cornerstone Visual Media Solutions Limited | Professional & scientific | 2020 |
| Cornfield Homes Limited | Real estate | 2003 |
| Corporate Actions Platform Limited | Information & communication | 2025 |
| Corporate Care Limited | Health & social care | 2025 |
| Corrpro Companies Europe Limited | Manufacturing | 1968 |
| Corrpro UK (Holdings) Limited | Financial services | 2023 |
| Cortex Property Limited | Real estate | 2023 |
| Cortonport Limited | Hospitality | 2001 |
| Coshabang (Richard House) Ltd | Administrative & support | 2020 |
| Cosiglobal Limited | Wholesale & retail | 2025 |
| Cosker Cable Services Ltd | Construction | 2024 |
| Cosker Property Services Ltd | Real estate | 2024 |
| Costandi Catering Limited | Hospitality | 2019 |
| Costays Hotels Ltd | Hospitality | 2025 |
| Count Care Services Ltd | Professional & scientific | 2017 |
| Country Valley Foods Ltd | Wholesale & retail | 1971 |
| Country Valley Meats Limited | Extraterritorial | 1999 |
| Country Valley Wholesale Foods Limited | Wholesale & retail | 2008 |
| County Durham Homes Limited | Real estate | 2016 |
| Courtfield Trading Limited | Professional & scientific | 2004 |
| Covercat Equipment Limited | Other services | 2011 |
| Covercat Pipeline Engineering Limited | Manufacturing | 2001 |
| Coverdale Capital Limited | Financial services | 2026 |
| Coverdale Educational Resources Ltd | Education | 2019 |
| Cozy House by Ngor Ltd | Construction | 2025 |
| Cozy Quarters Property Management Ltd | Households | 2025 |
| CP Management Services Ltd | Professional & scientific | 2015 |
| CP Rigging Services Ltd | Administrative & support | 2019 |
| CP Tooling & Machinery Limited | Wholesale & retail | 2015 |
| CPD LOG Plus Ltd | Information & communication | 2013 |
| CPH Contract Furniture Ltd | Wholesale & retail | 2019 |
| CPJ Housing Limited | Households | 2025 |
| Cprice Offshore Limited | Manufacturing | 2019 |
| Cprs Offshore Ltd | Administrative & support | 2012 |
| CPS (NE) Ltd | Professional & scientific | 2015 |
| CPS Renewables Limited | Construction | 2025 |
| CR Bainbridge Logistics Ltd | Transport & logistics | 2025 |
| Crackerbox 28 Limited | Other services | 2013 |
| Craft and Create North East CIC | Arts & recreation | 2025 |
| Craftsman Innovator Ltd | Manufacturing | 2026 |
| Craggs & Co Farms Limited | Agriculture & fishing | 2017 |
| Craig Steer Limited | Professional & scientific | 2023 |
| Craig Walker Locum Services Ltd | Health & social care | 2023 |
| Crathorne Cricket Club 2019 Ltd | Arts & recreation | 2019 |
| Craven Arms Homes Limited | Construction | 2017 |
| Crawford Solutions (UK) Limited | Administrative & support | 2014 |
| Crazy Price Carpets Ltd | Wholesale & retail | 2024 |
| Create Architecture Ltd | Professional & scientific | 2014 |
| Creation Pictures Limited | Information & communication | 2015 |
| Creations for Life Limited | Wholesale & retail | 2016 |
| Creative Practise CIC | Education | 2020 |
| Creative Village C.I.C. | Other services | 2013 |
| Credenex Ltd | Education | 2025 |
| Cresswell Investments (NE) Limited | Financial services | 2020 |
| Crest MO Ltd | Wholesale & retail | 2026 |
| Crestguild Limited | Professional & scientific | 2007 |
| CRM Medical Ltd | Professional & scientific | 2023 |
| Cromer Pre-School Limited | Education | 2021 |
| Cromer Properties Limited | Real estate | 2025 |
| Cross Country Sales Ltd | Wholesale & retail | 2019 |
| Crossans Cabling Company Ltd | Information & communication | 2026 |
| Crossburn Holiday Park Limited | Real estate | 2026 |
| Crossco (1298) Limited | Other services | 2012 |
| Crossco (1462) Limited | Financial services | 2022 |
| Crowdy Hall Ltd | Hospitality | 2022 |
| Crown Creative Ltd | Professional & scientific | 2025 |