| Campbells Engineering Services Ltd | Construction | 2024 |
| CANDL34 Property Ltd | Real estate | 2024 |
| Car Wash Cenetre Ltd | Administrative & support | 2026 |
| Career Management Limited | Professional & scientific | 1991 |
| Carlon Investments Limited | Financial services | 2025 |
| Carlton & Co Construction Limited | Construction | 2006 |
| Carlton & Co Consultancy Limited | Professional & scientific | 2007 |
| Carlton & Co Investments 2014 LLP | | 2014 |
| Carlton & Co Investments Ltd | Construction | 2008 |
| Carlton & Co Property Investments Limited | Real estate | 2004 |
| Carly Properties Ltd | Real estate | 2025 |
| Carmy Inspection Services Ltd | Construction | 2023 |
| Carter Group N.E Ltd | Financial services | 2026 |
| Cartyfire Ltd | Financial services | 2020 |
| Casa Olarului(The Potter's House) C.I.C. | Education | 2023 |
| Castle App Limited | Information & communication | 2021 |
| Cedarcrest Global Holdings Limited | Financial services | 2024 |
| Cedarcrest Global Ipco Limited | Financial services | 2024 |
| Cedarcrest Global Stockco Limited | Financial services | 2024 |
| Cedarcrest Global Trading Limited | Financial services | 2024 |
| Cedarwood Studios Ltd | Wholesale & retail | 2019 |
| Central Avenue Productions Ltd | Information & communication | 2011 |
| Centurion International Limited | Transport & logistics | 2018 |
| Certa (Small Works) Limited | Construction | 2023 |
| Certa Engineering Ltd | Professional & scientific | 2024 |
| Cestria Fabrications Limited | Wholesale & retail | 1986 |
| Chelsea Elizabeth Limited | Professional & scientific | 2025 |
| Chloe Hair Salon Limited | Other services | 2026 |
| Chris Howe Construction Limited | Construction | 2012 |
| Chris Lambert Engineering Ltd | Manufacturing | 2015 |
| Chromacoat Painters Ltd | Construction | 2025 |
| Ciel Creations Ltd | Manufacturing | 2017 |
| Circle Consulting Group Ltd | Professional & scientific | 2026 |
| CJ Fabrication and Access Solutions Ltd | Professional & scientific | 2017 |
| CJ Plumbing & Heating (NE) Ltd | Construction | 2018 |
| CK Holdings Limited | Financial services | 2019 |
| Cladrite Limited | Construction | 2014 |
| Claire Briggs Educational Psychologist Limited | Education | 2024 |
| Clarence Interiors (NE) Limited | Wholesale & retail | 2020 |
| Clean Street Solutions Ltd | Administrative & support | 2024 |
| Clique Salons Ltd | Other services | 2025 |
| Club 22 Ltd | Other services | 2025 |
| CMD Property Solutions Limited | Construction | 2014 |
| CMF Utilities Ltd | Construction | 2017 |
| CML Scaffolding Ltd | Construction | 2012 |
| Cobham Larder Limited | Wholesale & retail | 2022 |
| Cobots Online Limited | Professional & scientific | 2022 |
| Code Logistic Tech Ltd | Information & communication | 2024 |
| Coffee United (Aycliffe) Ltd | Manufacturing | 2020 |
| Coffee United (Bingley) Ltd | Manufacturing | 2023 |
| Coffee United (Catterick) Ltd | Hospitality | 2023 |
| Coffee United (Peterlee) Ltd | Manufacturing | 2020 |
| Coffee United (Skelmersdale) Limited | Manufacturing | 2019 |
| Coffee United Holdings Ltd | Financial services | 2020 |
| Coffee United Roasters Ltd | Wholesale & retail | 2023 |
| Collins Seafoods North East Limited | Wholesale & retail | 1986 |
| Collins Seafoods South West Ltd | Wholesale & retail | 2025 |
| Collins Seafoods Yorkshire Limited | Wholesale & retail | 2001 |
| Commercial Expert Limited | Financial services | 2008 |
| Commplex Property Services Ltd | Real estate | 2024 |
| Community Challenge Ltd | Arts & recreation | 2025 |
| Complete Group (Cumbria) Ltd | Other services | 2025 |
| Complete Group (Kent) Limited | Administrative & support | 2026 |
| Complete Network Shipping (NE) Limited | Transport & logistics | 2022 |
| Complete Sales Solutions Ltd | Professional & scientific | 2016 |
| Complete Weed Control Limited | Professional & scientific | 1993 |
| Complete Weed Control Trading Limited | Administrative & support | 2010 |
| Compton Robb Limited | Health & social care | 2024 |
| Conduit Medical Ltd | Professional & scientific | 2023 |
| Connor Dunlavey Fitness Academy Limited | Arts & recreation | 2025 |
| Contego Environmental Services Ltd | Other services | 2009 |
| Contract Associates (NE) Limited | Information & communication | 2017 |
| Cookhouse Design York Ltd | Wholesale & retail | 2011 |
| Cooper Cladding & Sons Ltd | Construction | 2026 |
| Cooper Cladding Limited | Construction | 2017 |
| Copperstone Trading Ltd | Hospitality | 2025 |
| Corecare N/A Ltd | Education | 2010 |
| Corehaus (Maltby) Limited | Construction | 2020 |
| Costume Hire Ltd | Administrative & support | 2018 |
| Cpff Ltd | Wholesale & retail | 2019 |
| Crawley Holdings (SE) Ltd | Financial services | 2024 |
| Crear Publishing Ltd | Information & communication | 2023 |
| Creditscale Limited | Administrative & support | 1996 |
| Cumby Technical Services Ltd | Professional & scientific | 2019 |
| CUT Above the Rest Tiling Ltd | Construction | 2016 |
| Cyber PM Ltd | Information & communication | 2017 |
| D Ormston Consultancy Ltd | Transport & logistics | 2020 |
| Daintree Recruitment Ltd | Administrative & support | 2024 |
| Daisy Lane Play Cafe Ltd | Hospitality | 2026 |
| Dakota Holdings North East Ltd | Financial services | 2025 |
| Dalehills Limited | Manufacturing | 1985 |
| Dales Masonry Limited | Construction | 2023 |
| Damp FIX Property Care Ltd | Households | 2026 |
| Danesmoor Group Limited | Professional & scientific | 2012 |
| Danesmoor Limited | Wholesale & retail | 1993 |
| Daniel Mallett Limited | Construction | 2015 |
| Datfuse Ltd | Wholesale & retail | 2025 |
| Davies Morgan Limited | Financial services | 2025 |
| Day 18 Limited | Information & communication | 2024 |
| DBA 615 Ltd | Manufacturing | 2025 |