| C2 Design and Engineering Limited | Professional & scientific | 2024 |
| CAD Innovation Group Ltd | Construction | 2018 |
| Café DU Caméléon Ltd | Hospitality | 2025 |
| Cambridge Biorenewables Ltd | Energy | 2012 |
| Cambridge Daisy Ltd | Wholesale & retail | 2024 |
| Cameron George Ltd | Administrative & support | 2011 |
| Camphill Development Limited | Agriculture & fishing | 2014 |
| Canvas HQ Ltd | Manufacturing | 2020 |
| Caps OFF Catering Ltd | Hospitality | 2020 |
| Caps OFF Ltd. | Wholesale & retail | 2017 |
| Caregallant Ltd | Administrative & support | 2022 |
| Carline NE Limited | Wholesale & retail | 2023 |
| Carman & Co Ltd | Professional & scientific | 2009 |
| CARPETS2YOU Ltd | Wholesale & retail | 2017 |
| Carrolla Products Limited | Wholesale & retail | 1987 |
| Carter & Carter Properties Ltd | Construction | 2023 |
| Carter's Fish Restaurant Ltd | Hospitality | 2022 |
| Cassie’S Kitchen Limited | Hospitality | 2020 |
| Castflow Furnaces Ltd | Manufacturing | 2016 |
| Castle Sourcing Ltd | Wholesale & retail | 2026 |
| Castlefort Property Limited | Real estate | 2019 |
| Castlegate & Mowbray Park Management Company Limited | Households | 2014 |
| Cathedral Masonry Inspections Ltd | Construction | 2018 |
| CBS Installations Limited | Construction | 2025 |
| CC Logistics (NE) Ltd | Transport & logistics | 2018 |
| CCB Plumbing and Heating Engineers Limited | Construction | 2026 |
| CCK Gifts Ltd | Wholesale & retail | 2023 |
| Cclts Ltd | Hospitality | 2025 |
| CCN (North East) Limited | Professional & scientific | 2025 |
| CCT Engineering Services Ltd | Professional & scientific | 2019 |
| Cegestel Ltd | Professional & scientific | 2025 |
| Cell Properties Limited | Real estate | 2025 |
| Cello EOT Limited | Extraterritorial | 2025 |
| Centurion Fields (Adel) Management Company Limited | Households | 2013 |
| Century Commercial Ltd | Construction | 2024 |
| Century Demolition Ltd | Construction | 2021 |
| Certainty Estate Planners Ltd | Professional & scientific | 2022 |
| Chaircabinet Limited | Manufacturing | 2011 |
| Champion Gardens Ltd | Administrative & support | 2025 |
| Chapel Fell Veterinary Services Ltd | Professional & scientific | 2023 |
| Chapmans Public House Limited | Hospitality | 2013 |
| Charlotte Fleming Funeral Services Ltd | Other services | 2021 |
| Chateau Beaumont Limited | Education | 1993 |
| Cheesedale Ltd | Hospitality | 2018 |
| Cheldage Ltd | Professional & scientific | 2020 |
| Chicken Ting Ltd | Hospitality | 2025 |
| Chong Yuan Hong Limited | Wholesale & retail | 2025 |
| Chris LEE Kitchen Installations Limited | Construction | 2022 |
| Chris Powton Fencing Limited | Other services | 2015 |
| Chris Scott Music Ltd | Information & communication | 2024 |
| Chronicle Projects Ltd | Professional & scientific | 2025 |
| Church Farm Management Company (Tockwith) Limited | Households | 2021 |
| Cimexuk Ltd | Other services | 2013 |
| Cinder Hill Management Company Limited | Households | 2017 |
| CJC Property Investments Ltd | Real estate | 2019 |
| CJC Property Services Limited | Construction | 2023 |
| CJC Scaffolding Ltd | Construction | 2019 |
| CJD Roofing & Cladding Ltd | Construction | 2020 |
| CJS Piping Limited | Professional & scientific | 2025 |
| CJY Consultancy Ltd | Construction | 2018 |
| Clar Properties Limited | Real estate | 2024 |
| Clark Property Developments Limited | Extraterritorial | 2016 |
| Clark's Oils Limited | Manufacturing | 2024 |
| Clear Brew North Limited | Administrative & support | 2026 |
| Clearview Technical Limited | Information & communication | 2000 |
| Clement Transport Ltd | Transport & logistics | 2024 |
| Cleveland View Holdings Ltd | Transport & logistics | 2026 |
| CLICK2BUY Limited | Wholesale & retail | 2002 |
| Cliffords Clear Window Cleaning Ltd | Administrative & support | 2022 |
| Cloughton (Management Company) Limited | Real estate | 2018 |
| Clover Engineering Services Ltd | Professional & scientific | 2013 |
| Cloverleaf Consultancy Ltd | Professional & scientific | 2020 |
| Cmbp Leisure Ltd | Hospitality | 2016 |
| CMW Utilities Holdings Limited | Financial services | 2022 |
| CNC (North East) Limited | Professional & scientific | 2025 |
| CNN Engineering Limited | Other services | 2016 |
| Coach House Garage Limited | Wholesale & retail | 2003 |
| Coach Technology Ltd | Information & communication | 2025 |
| Cockton Hill News Ltd | Transport & logistics | 2025 |
| Cockton Hill Properties Ltd | Real estate | 2025 |
| Cockton Hill Social Club Ltd | Other services | 2024 |
| Coco N Food Ltd | Hospitality | 2024 |
| COE Steel Ltd | Manufacturing | 2024 |
| Cognista Consulting Ltd | Health & social care | 2026 |
| Coley Manufacturing Ltd | Manufacturing | 2025 |
| Collingwood HO Limited | Hospitality | 2020 |
| Comet Systems Limited | Professional & scientific | 2024 |
| Community Links | Administrative & support | 2009 |
| Company Solutions (UK) Limited | Manufacturing | 2002 |
| Complete Cladding Systems Limited | Construction | 2000 |
| Complex Recruitment NE Ltd | Administrative & support | 2025 |
| Computer Insight Ltd | Other services | 2010 |
| Comtek System Solutions Ltd | Professional & scientific | 2003 |
| Connection Flooring Limited | Wholesale & retail | 2012 |
| Connection Retail Limited | Wholesale & retail | 2012 |
| Conservatory & Window World Limited | Construction | 2002 |
| Converge Group Ltd | Information & communication | 2015 |
| Coolabah Ltd | Professional & scientific | 2020 |
| Copaiba Ltd | Wholesale & retail | 2010 |
| Copley Service Station Limited | Wholesale & retail | 2002 |